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Importation of ‘Hass’ Avocado Fruit (Persea Americana cv. Hass) 

from Mexico 

A Risk Asssesment

June 2003

U.S. Department of Agriculture (USDA) 

Animal and Plant Health Inspection Service (APHIS)

Plant Protection and Quarantine (PPQ) 

Center for Plant Health Science and Technology (CPHST) 
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Table of Contents 

Executive Summary........................................................................................................................ 1 

Introduction..................................................................................................................................... 4 

History of Avocado Importation from Mexico............................................................................... 6 

Key Safeguards on the Importation of Mexican Avocados............................................................ 8 

1. Field surveys ....................................................................................................................... 8 

Municipality Surveys.............................................................................................................. 8 

Orchard surveys ...................................................................................................................... 9 

2. Trapping............................................................................................................................ 10 

3. Field sanitation practices................................................................................................... 10 

4. Host resistance .................................................................................................................. 10 

5. Post-harvest safeguards..................................................................................................... 10 

6. Winter Shipping................................................................................................................ 11 

7. Packinghouse inspection and fruit cutting ........................................................................ 11 

8. Port-of-arrival inspection.................................................................................................. 12 

9. Limited Distribution.......................................................................................................... 13 

Summary of Key Safeguards .................................................................................................... 13

Pathway Assessment..................................................................................................................... 15 

Assessment of Weed Potential of Avocado.............................................................................. 15 

Pest List..................................................................................................................................... 16 

Identification of Quarantine Pests............................................................................................. 16 

Identification of Pathway Pests................................................................................................. 17 

Pathway Scenario Model .............................................................................................................. 19 

Pathway Scenario Model .............................................................................................................. 19 

N – Annual Number of Fruit Imported..................................................................................... 19 

P1 – Proportion of Avocados Infested...................................................................................... 19 

Q1 – Annual number of infested avocados reaching the United States.................................... 24 

P2 – Proportion of fruit that will reach commercial avocado production areas in the United 

States......................................................................................................................................... 24 

Q2 – Annual number of infested avocados that reach regions of the United States where 

avocados are grown commercially............................................................................................ 26 

Estimates of Consequences of Introduction.................................................................................. 27 

Seed weevils.............................................................................................................................. 29 

Stem weevil............................................................................................................................... 30 

Seed moth.................................................................................................................................. 31 

Discussion..................................................................................................................................... 33 

Conclusions................................................................................................................................... 34 

Preparation, Consultation and Review.......................................................................................... 43 

Appendix A: Pest List................................................................................................................... 44 

Table A-1: Pathogens................................................................................................................ 44 

Table A-2: Arthropods.............................................................................................................. 46 

Appendix B: Review of the Biology of Selected Pests................................................................. 51 

Appendix C: Review of Anastrepha Species................................................................................ 54 

Appendix D - Quantitative Risk Assessment Model .................................................................... 56 

Appendix E – Approximation of the quantity of Hass avocados.................................................. 74 

Appendix F – 7CFR§319.56-2ff................................................................................................... 87 
 

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Executive Summary 

This risk assessment responds to a request to remove certain restrictions on the 

importation of avocados from Mexico. Its purpose is to analyze the risks of expanding 

the existing Mexican Hass avocado import program to authorize imports of Mexican 

Hass avocados to all states during the entire year. This assessment was thus prepared 

to assist APHIS in evaluating the request from Mexican avocado growers to expand 

the scope of the existing Mexican Hass avocado import program. APHIS 

phytosanitary regulations currently restrict avocado imports to Alaska and 31 

northeastern and north central states and limit distribution to October 15 through April 

15. This risk assessment evaluates the importation of Mexican avocado fruit to the 

entire United States during all months of the year. It analyzes the plant pest risks 

associated with fresh ‘Hass’ variety avocado fruits (Persea americana) grown in the 

state of Michoacán, Mexico. 

The assessment lists one hundred sixteen avocado pests known to occur in Mexico that 

may have potential importance in the United States. After eliminating non-quarantine 

and non-pathway pests from the list, five pests (three seed weevils: Conotrachelus 

aguacatae, C. perseae, and Heilipus lauri; one stem weevil: Copturus aguacatae; and 

one seed moth: Stenoma catenifer) remain that have quarantine significance and are 

potentially able to follow the pathway. 

The systems approach for ‘Hass’ avocados imported from Mexico includes a set of 

independent, redundant, and overlapping phytosanitary measures that collectively 

reduce the risk of pest introduction into the United States . The first level of controls 

can detect infested areas with a high degree of confidence. Exporting municipalities 

and orchards in Michoacán have been surveyed annually for six years with negative 

results for four of the five pathway pests: Heilipus lauri, Stenoma catenifer, 

Conotrachelus aguacatae, and Contrachelus perseae. The remaining pathway pest, 

the stem weevil, Copturus aguacate, was detected in five surveys of orchards seeking 

to export to the United States over six years of surveillance. These five detections 

were part of field surveys (using traps, visual inspections and other sampling systems) 

and not part of the export fruit dissection program described below. Those positive 

surveys resulted in loss of export certification of the involved orchards until 

appropriate pest eradication measures were completed. 

Cutting and inspection of fruit is the second level of control designed to detect fruit 

infested with any of the five pathway pests. Samples of fruit are collected in orchards, 

packing houses, and ports of entry into the United States. No pests have been found in 

Mexican avocados in six years of fruit cutting and inspection. Over ten million fruit 

were examined (8.8 million in the orchards, 1.4 million in packing houses, and 

100,000 at border inspection) for pest larvae. If an infested avocado were found, a 

trace-back mechanism in the systems approach allows APHIS and Mexican authorities 

to identify the source orchard. These orchards will lose their export certification until 

appropriate pest eradication measures are completed. 
 

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The mitigations in the systems approach are designed to reduce the risk from pathway 

pests. The success of this approach is evident from the failure to detect even one pest 

or infested avocado despite continuous and concerted efforts. Avocado importations 

during the last six years have provided APHIS with valuable experience managing the 

systems approach and increased the Agency’s confidence in the efficacy of the 

safeguards. 

A quantitative model based only on the fruit cutting data predicts that the most likely 

number of imported, infested avocados is zero. Specifically, the most likely 

proportion of infested avocados was found to be zero; the 95% confidence interval 

ranged from 0 to 5.25×10-7 [that is, from 0 to 52.5/100,000,000]. 

A model that combined simulations of infested fruit with forecast number of fruit 

exported to the United States indicated a 95% level of confidence that the annual 

number of avocados distributed to avocado-growing counties in the U.S. will not 

exceed 66. 

Even if an infested avocado were to arrive at a region with host material, several

additional conditions are required for pest establishment: (a) The pest must survive in 

the avocado during transportation and storage; (b) The infested avocado must be 

discarded in close proximity to host material; (c) The pest must find a mate; (d) The 

pest must successfully avoid predation and other threats; (e) The adult pest must find 

appropriate host material; and (f) Suitable climatological and microenvironmental 

conditions must exist. Although information that would allow quantifying these 

conditions is not currently available, APHIS believes that collectively they 

substantially reduce the likelihood of pest establishment and the overall level of risk. 

The rate of avocado pests entering the United States in legally imported commercial 

fruit, if these pests are entering at all, is certainly far lower than the rate in prohibited 

avocados arriving at U.S. ports of entry in the baggage of travelers. APHIS-PPQ data 

(PIN309) indicate that pathway pests are routinely found in prohibited avocados 

intercepted in baggage and cargo at U.S. ports of entry. During the seventeen year 

period from 1985 to 2002, an average of thirty avocados infested with pathway pests 

were intercepted and denied entry into the United States each year. Between this 

period, 502 pathway pests were detected in intercepted avocados in baggage and 

cargo: Conotrachelus sp.: 242; Copturus sp.: 5; Heilipus sp.: 38; Stenoma sp.: 217. 

APHIS estimates that more than 80% of prohibited fruit escape detection (Miller et al, 

1996; Meisner et al, 2003). Thus, 120 avocados infested with pathway pests are 

estimated to enter the United States each year through baggage and cargo. Prohibited 

avocados in baggage and cargo pose a substantially greater risk to U.S. agriculture 

than commercial imports of ‘Hass’ avocados from Mexico. 

In the past, fruit flies (Anastrepha spp.) were a major concern. Recent research (Aluja 

et al, 2002) conducted under both field and laboratory conditions prompted a reevaluation of the potential of Anastrepha spp. to infest ‘Hass’ avocados (Appendix C). 

 Based on this research, APHIS concluded that commercially produced ‘Hass’ 
 

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avocados are not natural hosts for the Anastrepha spp. considered. 

Finally, we note that as important as are the results of the quantitative model, we 

cannot ignore the risk-reducing effects of the systems approach, not all of which are 

captured by the quantitative model but are evidenced in USDA’s experience with the 

program and fruit sampling information. We believe the repeated surveys, 

inspections, and the other requirements of the systems approach reduce risk 

substantially. Our confidence in these surveys and inspections is reinforced, first, by 

repeated site visits by APHIS headquarters personnel; second, by the active 

participation of APHIS field personnel in the surveys; third, by the redundancy of the 

systems approach mitigations; and fourth, by the fact that examination of over ten 

million fruit has not revealed even one pest. 
 

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Introduction 

This risk assessment responds to a request to remove certain restrictions on the 

importation of ‘Hass’ avocados from Mexico; its purpose is thus to analyze the risks of 

expanding the existing Mexican Hass avocado import program to authorize imports of 

Mexican Hass avocados to all states during the entire year. This assessment was prepared 

to assist APHIS in evaluating the request from Mexican avocado growers to expand the 

scope of the existing Mexican Hass avocado import program. The request to expand the 

existing Mexican avocado import program will be referred to as the proposed modified 

systems approach. APHIS regulations currently restrict avocado imports to 31 

northeastern and north central states, Alaska, and the District of Columbia. Shipment and 

distribution are allowed only from October 15 to April 15. This pest risk assessment 

evaluates the importation of Mexican avocado fruit to the entire United States and during 

all months of the year. It analyzes the plant pest risks associated with fresh ‘Hass’ variety 

avocado fruits (Persea americana) grown in the state of Michoacán, Mexico. Whereas 

the current system is used as a reference point, this assessement focuses on the risks 

associated with a program that is expanded both geographically and in time. 

This assessment first identifies and lists all pests of potential importance to the United 

States associated with Mexican avocados (Appendix A). Non-quarantine and nonpathway pests are then eliminated from further consideration. The assessment next 

estimates the likelihood of introduction for the remaining pathway pests. Two 

quantitative endpoints of the likelihood of introduction of pathway pests are estimated: 

the number of infested avocados reaching the United States each year and the number 

of infested avocados reaching avocado producing regions in the United States each 

year. Given an importation of an infested avocado, the additional steps leading to pest 

spread and establishment are evaluated using qualitative evidence. Finally, the 

consequence of introduction is considered. 

This document does not attempt to address the level of pest infestation that constitutes 

acceptable or negligible risk. However, information on the number of pathway pests 

in prohibited fruit in the baggage and cargo arriving in the United States is provided 

for comparison. 

APHIS has completed several risk assessments of avocados imported from Mexico 

(USDA 1995, 1995a, 1996, APHIS 2001b). This document updates and supplements 

evidence presented in those assessments and analyses. Also, this assessment considers 

new evidence of the potential for Anastrepha fruit flies to infest ‘Hass’ avocados and 

the results of avocado inspections completed by Mexican and APHIS officials. To the 

extent possible, key elements of previously published risk assessments and APHIS 

documents are presented here to permit the reader to understand this assessment 

without reference to previous work. Some elements, however, are incorporated by 

reference; the relevant documents are available on the internet at: 

http://www.aphis.usda.gov/ppq/avocados/. 

Whereas the terms “assessment” and “assessment” have similar meaning, in the area 
 

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of risk assessment the term “assessment” is usually employed as a broader concept to 

describe a process where the hazard is characterized, impacts are assessed, mitigations 

evaluated, and communications considered. Risk “assessment” usually refers to the 

characterization of the hazards and the evaluation of impacts (that is, “assessment” 

sensu stricto, does not include risk mitigation and risk communication). Because this 

assessment is part of a process that will include separate communication elements, and 

for consistency with previous documents, we will refer to this document as a risk 

“assessment”. This document will evaluate hazards, impacts and evaluate some 

mitigation alternatives. 
 

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History of Avocado Importation from Mexico 

Quarantine 56 (7 CFR § 319.56) provides general regulatory authority for importation 

of fruits and vegetables. In 1973, the specific avocado quarantine was incorporated 

into the general nursery stock (7 CFR § 319.37) and fruit and vegetable quarantines 

(Quarantine 56, 7 CFR § 319.56). 

USDA has restricted importation of 

Mexican avocado fruit since 1914 to 

protect the phytosanitary health of U.S. 

avocado production. The primary 

justification for the 1914 restriction was 

the presence of an avocado seed weevil 

(Heilipus lauri) in Mexico (Table 1). 

Since 1914, Mexican agricultural 

officials and exporters, as well as U.S. 

importers of agricultural commodities 

have petitioned repeatedly for 

authorization to import Mexican avocado fruit into the United States. 

In 1992, Mexican authorities asked APHIS to consider allowing the importation of 

‘Hass’ avocados from Mexico to any destination in the United States. APHIS 

conducted a risk assessment and concluded that Mexican avocados risks associated 

with imports into Alaska were low because imported pests could not survive or 

establish there. That assessment used a decision sheet format (Attachments 1 and 2 of 

Risk Management Assessment: A Systems Approach for Mexican Avocados, APHIS, 

1995b). A proposed rule was published in the Federal Register in 1992 (APHIS, 

1992) and the final rule was published the following year (APHIS, 1993a). At the 

current time, ‘Hass’ avocados from Michoacán can be imported to Alaska under the 

conditions specified in 7CFR§319.56-2bb. 

Interest in export of Mexican avocado fruit to other states continued after 1993 with 

Mexico making repeated requests. APHIS formed an oversight group to consider 

Mexico’s requests. The APHIS Oversight Group met several times and made three 

trips to the Mexican avocado growing areas in Michoacán, Mexico. APHIS developed 

two documents relevant to avocado imports: Potential Economic Impacts of an 

Avocado Weevil Infestation in California (APHIS, 1993b), and Economic Impact of 

the Establishment of Mexican Fruit Fly in the United States (APHIS, 1993c). 

In July 1994, Sanidad Vegetal, the plant protection branch of the Mexican Ministry of 

Agriculture and Water Resources, requested that APHIS allow Mexico to export fresh 

‘Hass’ avocados from approved orchards in approved municipalities in Michoacán 

into the northeastern United States. After reviewing Mexico’s proposal, APHIS 

published an Advance Notice of Proposed Rulemaking (59 FR 59070-59071, Docket 

No. 94-116-1) in the Federal Register (November 15, 1994) announcing APHIS’ 

receipt of the request. Also, APHIS officials prepared two documents as part of the 

Table 1 - Chronology of Mexican Avocado Importation

Year Event 

1914 APHIS prohibits importation of avocados from 

Mexico because of seed weevils. 

1993 APHIS allows entry of Mexican Hass avocados into 

Alaska under certain conditions. 

1997 APHIS allows entry of Mexican Hass avocados from 

Michoacán, Mexico to 19 northeastern states from 

November to February, subject to certain 

phytosanitary requirements. 

2001 APHIS allows entry of Mexican Hass avocados from 

Michoacán, Mexico to 31 northeastern and north 

central states from October 15 through April 15, 

subject to certain phytosanitary requirements. 
 

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risk assessment. The first document, “Risk Management Assessment: A Systems 

Approach for Mexican Avocado,” (USDA, 1995b), is an assessment of procedures to 

reduce pest risk associated with Mexican ‘Hass’ avocados. The second document 

“Importation of Avocado Fruit (Persea americana) from Mexico: Supplemental Pest 

Risk Assessment” (USDA, APHIS, 1995a) includes a quantitative assessment of the 

likelihood of introducing certain pests as well as an assessment of the consequences of 

such introduction. The assessment estimated that the risk was low with a systems 

approach in place (i.e., a systems approach as described in 

http://www.aphis.usda.gov/ppq/avocados/). A final rule was published in the Federal 

Register in February, 1997 to allow the importation of fresh ‘Hass’ avocados from 

Mexico under certain conditions (USDA, APHIS, 1997). The 1997 rule allowed 

imports of avocados to nineteen northeastern states (Connecticut, Delaware, Illinois, 

Indiana, Kentucky, Maine, Maryland, Massachusetts, Michigan, New Hampshire, 

New Jersey, New York, Ohio, Pennsylvania, Rhode Island, Vermont, Virginia, West 

Virginia, and Wisconsin) plus the District of Columbia but limited shipments to the 

months from November through February. Climatic conditions in those states during 

the winter months precluded the establishment of any exotic plant pests that might 

accompany avocados from Michoacán, Mexico. 

In September 1999, the Government of Mexico requested that APHIS further expand 

the importation of ‘Hass’ avocados into the United States in accordance with the 

Sanitary and Phytosanitary (SPS) agreement and the North American Free Trade 

Agreement (NAFTA). APHIS considered the request and finalized the current rule for 

avocado importation from Mexico in 2001. Under the regulations (7CFR Sec. 319.56-

2ff) avocados are currently allowed to enter 31 states and the District of Columbia 

between October 15 through April 15 of the following year. The current importations 

are subject to a series of mitigations, described in “Risk Management Assessment: A 

Systems Approach for Mexican Avocados” (USDA, 1995b, available at: 

http://www.aphis.usda.gov/ppq/avocados/). Under the regulations (7CFR Sec. 

319.56-2bb) avocados may be imported in Alaska throughout the year under less 

restrictive conditions. 
 

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Key Safeguards on the Importation of Mexican Avocados 

The importation of Mexican avocados is managed using a “systems approach.” This 

refers to a set of independent, redundant and overlapping phytosanitary measures that 

collectively mitigate the risk of pest introduction into the United States (Anon, 2002; 

and NAPPO Glossary of Phytosanitary Terms). The systems approach is also 

described as the integration of different pest risk management measures, at least two 

of which act independently, and which reduces the risk of introduction of pests (FAO, 

2002). The systems approach for ‘Hass’ avocados has successfully protected U.S. 

agriculture for several years. Avocado importations during the last six years provided 

APHIS with valuable experience managing the systems approach and increased the 

Agency’s confidence in the efficacy of the safeguards. 

Key safeguards in the systems approach are listed in Table 2 and described below. 

The expanded distribution of avocados requested by Mexico will eliminate two 

components (components 6 and 9, Table 2), allowing avocados to enter all fifty states 

and during all times of the year. 

1. Field surveys 

Current regulations (7 

CFR § 319.56-2ff (c) (ii)) 

and the proposed 

modification to the 

systems approach both 

require annual surveys of 

orchards and 

municipalities. 

Municipality Surveys

Current regulations and 

the proposed systems 

approach require the 

Government of Mexico to 

conduct annual area 

surveys of Michoacán 

municipalities for Heilipus lauri, Stenoma catenifer, Conotrachelus aguacatae and 

Contrachelus perseae (7 CFR§319.56-2ff (c)(1)(ii)). The surveys must cover at least 

300 randomly selected hectares in each municipality and include portions of 

commercial orchards, wild areas and backyards. The surveys include foliage 

sampling, fruit cutting, and visual inspection. Foliage samples are collected by 

beating the lower branches of a tree over a white tarpaulin. Foliage and other material 

falling onto the tarpaulin are examined for pests. The survey must be conducted 

during the growing season and completed prior to the harvest of the avocado. The 

survey sampling method is calibrated to detect pests if they are present in one percent 

or more of the area surveyed at a 95% confidence level (USDA, 1995b; USDA, 2003;

http://www.aphis.usda.gov/ppq/avocados/workplan_2003.pdf). 

Table 2. Components of the Current and Modified 

Systems Approach for Avocados imported from Mexico

Current components Modifications to components 

1. Field Surveys (municipalities and 

orchards) 

Anastrepha spp. survey requirement 

removed 

2. Trapping Activities Anastrepha spp. trapping requirement 

removed 

3. Field Sanitation 

4. Host Resistance 

5. Post-Harvest Safeguards 

6. Winter Shipping Only (Oct 15 – 

April 15) 

No restriction on shipping season 

7. Packing House Inspection and Fruit Cutting 

8. Port-or-Arrival Inspection and Clearance Activities 

9. Limited Distribution (31 states and 

the District of Columbia) 

No restriction on distribution. 

Requirement for sealing trucks during 

transport within the United States 

removed. 
 

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Six years of surveys found no evidence of the four pathway pests (Heilipus lauri, 

Stenoma catenifer, Conotrachelus aguacatae and Contrachelus perseae) in Michoacán 

municipalities certified to export to the United States (Tables 5a and 5b). Some 

experts doubt that climatic conditions in Michoacán are suitable for Stenoma catenifer

or that the pest is even able to infest the ‘Hass’ variety of avocado (USDA/APHIS, 

2001b Appendix E&F). The existence of Contrachelus aguacate and Heilipus lauri in 

Michoacán at any time in the past is questionable although they have been found in 

nearby states (USDA/APHIS, 2001b Appendix F). The seed weevil, Conotrachelus 

perseae, occurs only in one small area of Michoacán near Ziracuaretiro. Mexico has 

quarantined this area and conducted an eradication program for the past three years 

during which time the quarantined area has been reduced from 600 to 140 acres 

(USDA/APHIS, 2001b Appendix F). We note that the detections of Conotrachelus

have not occurred as part of the export fruit dissection, but as part of separate 

sampling procedures as described above. We further note that when quarantine pests 

have been found, those areas have been eliminated from the export program and 

eradication programs have ensued. This clarification is offered to explain the absence 

of pests in six years of systematic export fruit dissections as contrasted with sampling 

using alternative methods in all areas (not just export orchards) which has resulted in 

reports from the region (and subsequent eradication or exclusion efforts) of pests such 

as Conotrachelus and Copturus. 

APHIS monitors Mexico’s compliance with municipality survey procedures in 

Michoacán. If Heilipus lauri, Stenoma catenifer, Conotrachelus aguacatae or 

Contrachelus perseae were detected, the affected municipality would lose its pest-free 

certification. Sanidad Vegetal is required to inform APHIS about infestations and 

control/eradication measures and suspend avocado exports from the municipality 

involved. Exports could resume only if and when APHIS were to determine that 

Mexico has implemented effective measures and eradicated the pest from the infested 

municipality. 

Orchard surveys

The current and proposed modified systems approach requires Mexican authorities to 

conduct annual surveys of orchards for the fifth pathway pest, the stem weevil, 

Copturus aguacatae. 

Registration of orchards in the export program requires participation in a multi-level 

pest inspection and approval process outlined in Mexican regulation NOM-066. The 

registration process begins when a grower petitions the Junta Local de Sanidad 

Vegetal (JLSV - the local equivalent to a U.S. county agricultural office), to 

participate in the export program. Inspectors from the JLSV office visit the 

prospective orchard biweekly and conduct general pest inspections. After the JLSV 

inspector identifies the pest-free export-eligible orchards, the Comite Estatal de 

Sanidad Vegetal (CESV - equivalent to a state agricultural office in the U.S.) again 

inspects those orchards and certifies freedom from the five pathway pests. Orchards 

that pass this inspection are approved to export for the next season. APHIS and CESV 
 

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inspectors conduct a third inspection the following year during the avocado growing 

season. Final approval to export is only given after an orchard is determined to be free 

of pathway pests in all three inspections. 

Fruit are sliced and inspected for pathway pests in the orchards during the surveys. A 

total of 8.8 million avocados from export orchards were inspected over the previous 

six years (an average of 1.4 million avocados per year) and no pathway pests were 

found. 

APHIS monitors compliance with orchard survey requirements and APHIS personnel 

participate in the annual surveys. If the stem weevil, Copturus aguacatae is detected, 

the affected orchard is denied export certification for the entire shipping season. 

Exports can resume only when APHIS determines that Mexico has implemented 

effective measures and eradicated the pest from the infested orchard. During the past 

six years of surveillance, stem weevils were detected in five orchard surveys. 

2. Trapping 

The current rule requires trapping and field bait treatment for fruit flies Anastrepha 

ludens, A. serpentina, A. obliqua, and A. striata. Based on recent research, APHIS 

believes that commercial ‘Hass’ avocados are not natural hosts for Anastrepha species 

that occur in Mexico (Appendix C). 

3. Field sanitation practices 

The current and proposed modified systems approach require orchard sanitation 

measures. Dead branches on avocado trees must be pruned. Fallen fruit must be 

collected and removed weekly. Fallen fruit, which are usually overripe or damaged, 

are more susceptible to pest infestation, including fruit flies (Anastrepha spp.). 

Pruning helps to prevent infestations of the stem weevil (Copturus aguacate) (USDA, 

APHIS; 1995b). Field sanitation measures are intended to maintain healthy orchards, 

thus reducing their susceptibility to pest infestation. 

Field sanitation practices are the responsibility of the avocado grower or orchard 

owner. Junta Local de Sanidad Vegetal (JLSV) monitors compliance. Sanidad 

Vegetal and APHIS assess field sanitation practices during annual orchard surveys.

4. Host resistance 

The natural resistance of ‘Hass’ avocados to certain Anastrepha spp. found in Mexico 

was, and will continue, to be used as a safeguard. A discussion of the effectiveness of 

this safeguard can be found in Appendix C. Hass avocados are easily distinguishable 

from other varieties by their black color, rugose skin and other characteristics when 

ripe. Other varieties are green or smooth skinned. Accidental or deliberate 

substitution of other varieties is unlikely and can be easily detected. 

5. Post-harvest safeguards 

The current systems approach includes requirements designed to ensure that avocados 

originate from certified orchards and to maintain the identity of the orchard from 
 

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harvest until arrival at market in the United States. Refrigeration is required during 

transportation and storage. These requirements will be maintained in the proposed 

modified systems approach. 

In the orchard, avocado field boxes must be marked with the registration number of 

the orchard (7CFR§319.56-2ff(c)(2)(v)). At the packinghouse, the identity of the 

orchard must be maintained from the field boxes to the shipping containers 

(7CFR§319.56-2ff(c)(3)(vii)). Prior to packing in boxes, each avocado must be 

labeled with the registration number of the packing house. In addition, avocados must 

be packed in boxes marked with the identity of the grower, packinghouse, and 

exporter. If a pest were found in an avocado at any point from the packinghouse to the 

market, APHIS and Sanidad Vegetal could determine the orchard where it was grown. 

 Although no pathway pests have been detected in the past six years, this trace-back 

mechanism is an important safeguard designed to allow U.S. and Mexican authorities 

to determine the cause of a breakdown in the systems approach and respond with 

appropriate measures. 

All shipments of avocados must be accompanied by a phytosanitary certificate issued 

by Sanidad Vegetal certifying that the conditions specified in the regulations have 

been met. Shipments are sealed during transit to the port of first arrival and 

certificates are checked by DHS inspectors at the port of first arrival. These measures 

ensure that shipments of fruit originate from certified orchards that are managed in 

accordance with the requirements of the rule. 

The current and proposed modified systems approachs require transportation of 

avocados in refrigerated trucks or containers. In addition, avocados are refrigerated 

during storage as part of normal retail marketing and distribution of fruit. Optimum 

storage temperatures for ‘Hass’ avocados range from 5 ̊ to 8 ̊C 

(www.postharvest.com.au/Avocado_Hass.pdf). Insects develop very little if at all 

below 4 to 10 degrees C 

(http://www.ento.vt.edu/Fruitfiles/Understanding_Degree_Days.html) and commonly 

exhibit high mortality as well, especially at the lower storage temperatures (Stinner et 

al. 1974; Wagner et al., 1984). 

6. Winter Shipping 

The current rule limits the shipment and distribution of Mexican avocados to the 

timeframe between October 15 and April 15 (7 CFR § 319.56-2ff (a) (2)). This 

restriction will be removed in the proposed modified systems approach. 

7. Packinghouse inspection and fruit cutting 

The packinghouses in Mexico that process avocados for export to the United States 

must be registered with Sanidad Vegetal and must be listed in the annual work plan 

that Sanidad Vegetal provides to APHIS. The requirements for packinghouses 

specified in the current rule include several mitigations designed to exclude fruit flies, 

detect infested avocados, and allow trace-back if infested avocados are found. The 

proposed modified systems approach will retain these packinghouse requirements. 
 

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Avocados must be moved from the orchard to the packinghouse within 3 hours of 

harvest or covered to exclude pests (7CFR§319.56-2ff((c)(2)(v)). During shipment to 

the packinghouse, the avocados must be covered or enclosed. At the packinghouse 

screens are required on windows and double doors on entrances (7CFR§319.56-

2ff((c)(3)(ii)). These measures are all designed to exclude fruit flies (Anastrepha

spp.). Although Hass avocados are not natural hosts for the fruit fly species 

commonly found in Mexico, some evidence suggests Anastrepha spp. may be able to 

infest avocados several hours after they are picked if fruit are forcibly exposed to 

sexually mature, gravid females under artificial laboratory conditions (Appendix C). 

Stems and leaves must be removed from the fruit prior to packing in boxes. This 

requirement helps to ensure that pests infesting parts of the plant other than the fruit 

are excluded from the shipment. Copturus aguacatae is the only pathway pest that 

usually infests the stem rather than fruit. 

Inspectors in the packinghouses slice and inspect 300 fruit per export shipment for the 

presence of the larva of pathway pests. In practice, this is accomplished by sampling 

75 from each field truck arriving at the packing house from the orchard. Sanidad 

Vegetal inspectors have examined nearly 250,000 avocados per year for the past six 

years. A total of 1.5 million avocados were examined; no pests were found. 

Packinghouses must label each fruit with a sticker with the registration number of the 

packinghouse and mark the boxes or crates with the identity of the grower, 

packinghouse, and exporter. The identity of the avocados must be maintained from 

field boxes or containers to the shipping boxes so the avocados can be traced back to 

the orchard in which they were grown if a pest were found at the packinghouse or the 

port of first arrival in the United States. 

Another post-harvest requirement is refrigeration of trucks from the packinghouse to 

the market in the United States (7 CFR§319.56-2ff(3)(c)(viii)). The lethality of 

refrigeration on the five pathway pests is unknown but refrigeration does delay the 

development of all of the five pests. At the packinghouse, boxes must be placed in a 

refrigerated truck or refrigerated container and remain in that truck or container while 

in transit through Mexico to the United States. Prior to leaving the packinghouse, 

Sanidad Vegetal must secure the truck or container with a seal that will be broken if 

the truck or container is opened. Once sealed, the refrigerated truck or container must 

remain unopened until it reaches the United States. 

8. Port-of-arrival inspection 

Mexican avocados currently may enter the United States only at designated locations. 

DHS inspectors ensure that the seals on the trucks are intact upon arrival and that the 

shipment is accompanied with a phytosanitary certification issued by Sanidad Vegetal 

certifying compliance with all provisions of the rule. 

At the port of first arrival DHS inspectors must inspect avocados from each shipment 
 

 Page 13 

for pests (7CFR § 319.56 – 2ff (d)). Currently, DHS inspectors sample at least 30 

boxes and/or 30 fruit per shipment. DHS (formerly, APHIS) inspectors have 

examined approximately 20,000 avocados per year for the past six years. A total of 

approximately 117,000 avocados have been examined; no pests were found. 

These requirements remain unchanged in the proposed modified systems approach. 

Summary of Key Safeguards 

Surveys for pathway pests in municipalities and orchards are the first line of defense 

in preventing pests from entering the import pathway. Inspection of fruit at 

packinghouses and ports of entry is a secondary line of defense. In addition, fruit are 

sliced and inspection in orchards, packing houses, and ports of arrival in the United 

States. If a pathway pest is detected, APHIS and Mexican officials can trace back to 

the orchard of origin to determine the cause of the breakdown and take corrective 

action. In six years of imports, no pathway pests have been detected in fruit in the 

import pathway. 

APHIS conducted a risk management assessment for Mexican ‘Hass’ avocados in 

1995 and described the degree to which the various elements of the systems approach 

are expected to mitigate the pest risk associated with such importations. The 

assessment concluded that the cumulative effects of the systems approach lowered the 

risk of all target pests and that even if one of the mitigation measures should 

completely fail, the effect of the other measures would maintain risk at a low level. 

APHIS again reviewed the Mexican ‘Hass’ avocado import program in 2001 in 

response to a request from the California Avocado Commission (USDA, 2001b; 

http://www.aphis.usda.gov/ppq/avocados/#support). As part of the review, a team of 

APHIS officials visited avocado production areas in Michoacán, Mexico. The site 

visit team observed trapping and orchard sanitation practices in Michoacán and 

concluded that the program was operating in compliance with the regulations. Also, 

the USDA review team visited one of ten agricultural quarantine highway checkpoints 

staffed by Comite Estatal de Sanidad Vegetal (CESV) situated on the borders of all of 

the export approved municipalities. All fruit trucks must stop at these checkpoints 

both entering and leaving the municipalities to verify documentation and contents of 

the truck. The agricultural inspectors also make random checks of passenger vehicles 

and non-fruit trucks entering the municipalities as a phytosanitary measure to maintain 

freedom from avocado pests not known to occur in the municipality. The review team 

concluded that the surveillance activities used in Mexico for area and production site 

approvals complied with 7 CFR § 319.56-2ff. APHIS believes JLSV’s biweekly yearround surveys in export orchards, CESV’s yearly spring surveys from March through 

June of avocado export orchards, backyard avocado trees and wild avocado trees and 

the joint APHIS/CESV summer survey from July through September are adequate to 

meet the surveys required in 7 CFR § 319.56-2ff(c)(1)(ii), 7 CFR § 319.56-2ff(c)(2), 

and 7 CFR § 319.56-2ff(c)(2)(i). 
 

 Page 14 

The review group reported the following for pest distributions (USDA 2001b): 

 The stem weevil, Copturus aguacate, occurs in Michoacán and in 

municipalities having orchards that export to the U.S. 

 The seed weevil, Conotrachelus perseae, occurs in Michoacán but not within 

exporting municipalities. In Michoacán, it occurs only in one small area near 

Ziracuaratiro. This area is under eradication. The quarantined area has been 

reduced from more than 600 acres to 140 acres (as of the USDA 2001b 

review). 

 The seed weevils, Conotrachelus aguacate and Heilipus lauri, are not known 

in Michoacán.

 The seed moth, Stenoma catenifer, may not occur in Michoacán and would 

likely be detected by current sampling systems. 
 

 Page 15 

Pathway Assessment 

This risk assessment was pathway-initiated, meaning that the assessment was initiated 

in response to the request by the Mexican government to export a particular 

commodity, namely avocados. 

The approach taken in this assessment was first to identify all pests of Mexican 

avocados. From this initial list, non-quarantine pests (as defined by NAPPO and FAO 

above) were eliminated. From the list of quarantine pests, those pests that are not 

normally found on the plant part proposed for export (eg, those pests that would infest 

only roots) were eliminated. We then estimated the likelihood and consequence of 

introduction for the remaining pests. These steps include the three stages of the FAO 

guidelines plus additional detail consistent with the IPPC standard (FAO, 1995; FAO, 

2002): 

1. Assessment of the weed potential of avocados. 

2. Development of a Pest list. 

3. Identification of quarantine pests. 

4. Identification of pathway pests for further consideration. 

5. Estimation of the likelihood of introduction of the pests that are both 

quarantine and pathway pests under the conditions specified. 

6. Estimation of the consequences of introduction. 

In this document we address each of these seven steps. 

Assessment of Weed Potential of Avocado 

The initial step after 

receiving a request for 

importation of a 

commodity is to analyze 

the weed potential of the 

commodity itself. The 

process of evaluating the 

potential of avocados to 

become weeds is shown 

in Table 3. We found 

that the weed potential of 

avocado was low and the 

table details the evidence 

used in making this 

determination. Avocados 

of many cultivars, 

including ‘Hass’ are 

currently grown in 

several areas of the United States for fruit production and are also marketed as 

landscape plants. 

Table 3 – Weed Potential of Avocado

Species: Avocado, Persea americana

To determine weed potential we followed the format below. 

Is the species listed in: 

 NO Geographical Atlas of World Weeds (Holm, 1979) 

 NO World's Worst Weeds (Holm, 1977) 

 NO Report of the Technical Committee to Evaluate Noxious Weeds; Exotic 

 Weeds for Federal Noxious Weed Act (Gunn & Ritchie, 1982) 

 NO Economically Important Foreign Weeds (Reed, 1977) 

 NO Weed Science Society of America List (WSSA, 1989) 

 NO Is there any literature reference indicating weed potential (e.g., 

AGRICOLA, CAB, Biological Abstracts, AGRIS; search "avocado" combined 

with "weed"). 

IF: All of the above answers are no, 

THEN: proceed with the pest risk assessment. 

Source: FAO, 1995. International standards for phytosanitary measures. Section 1 

– Import Regulations: Guidelines for Pest Risk Assessment (Draft standard). 

Secretariat of the Internaitonal Plant Protection Convention of the Food and 

Agriculture Organization of the United Nations. Rome, Italy. 
 

 Page 16 

Pest List

We identified all Mexican avocado pests with potential economic importance in the 

United States [Appendix A, tables A-1 (pathogens) and A-2 (arthropods)]. These lists 

were generated through review of the following references and resources: 

− Literature reviews using the AGRICOLA and CABPEST databases. 

− Previous decision sheets covering the importation of avocados from Mexico, 

Jamaica, and Central America. 

− The United States catalogue of intercepted pests and interception records. 

− C.M.I. Distribution Maps and Descriptions of Plant Pathogenic Fungi and 

Bacteria. 

− Texts and indices of plant pests and pathogens as listed in the bibliography 

section at the end of this assessment. 

− APHIS' files on pests not known to occur in the United States (e.g., PNKTO's 

“Pests Not Known to Occur” and INKTO's “Insects Not Known To Occur”). 

All pests listed in Table A-1 and A-2 are present in Mexico. For each pest in Table A1 and A-2: 

− Whether the pest occurs in the U.S is indicated. 

− Information on the biology and regulatory history (e.g., interception records) is 

provided; all pests intercepted at U.S. ports on avocado fruit from Mexico are 

included on the pest list. 

− Selected references on the biology/distribution of each pest are provided. 

Identification of Quarantine Pests 

From the list of Mexican avocado pests identified in the assessment, all those that 

were not “quarantine” pests were eliminated. A quarantine pest is defined by the 

North American Plant Protection Organization (NAPPO) and the United Nations Food 

and Agriculture Organization (FAO) as, “A pest of potential economic importance to 

the area endangered thereby and not yet present there, or present but not widely 

distributed and being officially controlled” (FAO, 1995; NAPPO/FAO, 1991). The 

distribution of each pest was reviewed to determine if any official control programs 

exist. Only those pests that are absent from the United States or are present but are not 

widely distributed and are officially regulated fit the international standard for 

quarantine pests. 

In table A-1 and A-2 of appendix A, “MX” in the Distribution column indicates that 

the pest is present in Mexico and not in the United States (unless a US State is 

identified in the same column, using the two letter State abbreviation) and is therefore 

a quarantine pest. Of the 26 pathogens listed in table A-1 (Appendix A), three do not 

occur in the United States. Only those three are quarantine pests. Of the 86 

arthropods in table A-2 (Appendix A), 51 are quarantine pests (49 exist only in 

Mexico and an additional two exist in the US but are under official control as 

indicated in the comments for the table). 
 

 Page 17 

Identification of Pathway Pests 

From the list of quarantine pests, we eliminated those pests that are unlikely to follow 

the pathway. We reviewed the biology of each pest to determine if the pest is 

associated with the fruit and eliminated those that could not reasonably be expected to 

remain on the fruit after processing from further consideration. 

Previous assessments (APHIS, 1995a) considered certain Anastrepha species as pests 

likely to be associated with avocado fruit. Those earlier assessments concluded that 

avocados are either non-hosts or at best, poor hosts, and that the probability of 

association of Anastrepha with the ‘Hass’ avocado imports is low (Pest risk 

assessment, addendum and review APHIS 1995a, 1996, 2001). 

Recent research on four Anastrepha spp. (Aluja et al., 2002) prompted a re-evaluation 

of their designation as avocado pests (Appendix C). In field cages and laboratory 

trials, avocados were artificially exposed to large numbers of fertile females of four 

different species of Anastrepha: A. serpentina, A. ludens, A. striata, and A. obliqua. 

The conditions of exposure included both choice studies and no-choice studies. The 

choice studies included ‘Hass’ avocados and other cultivars. In the choice trials, 

avocado varieties other than ‘Hass’ were visited more frequently and had infestations 

that resulted in viable offspring. The no-choice studies included ‘Hass’ avocados 

only. In the no-choice studies, oviposition was attempted but infestation did not 

occur. Observations on the physiological responses to oviposition in ‘Hass’ cultivar 

avocados suggest that epicarp regeneration and callus formation inhibit larval 

development. 

Field observations by Mexican and U.S. inspection personnel are consistent with 

Aluja, 2000 (APHIS, 2001; table 5). Ten million avocados were dissected over the 

past six years as part of the inspection of avocados imports to the United States; none 

were found positive for Anastrepha spp. Based on Aluja et al, 2000 and the dissection 

data, we conclude that commercially produced ‘Hass’ avocados are not a natural host 

for the Anastrepha species considered. In table A-2 (Appendix A) a “z” in the 

comments field indicates that a pest is known to commonly attack or infest fruit and it 

would be reasonable to expect the pest may remain with the fruit during processing 

and shipment. The table in Appendix A was updated and the “z” removed from the 

comments column for A. ludens, A. opliqua, A. serpentina, and A. striata. 

The Mediterranean fruit fly (Medfly), Ceratitis capitata (Wiedemann) (Diptera: 

Tephritidae), was excluded from further consideration because it is absent from the 

export area. The Mediterranean fruit fly is a quarantine pest with considerable 

economic importance to the United States. However, the Mediterranean fruit fly is 

under active control in Mexico and is only found on the Mexico-Guatemala border. 

Five of the 54 quarantine pests could potentially follow the pathway. The three 

quarantine pathogens in Table 1-A were eliminated because they cause leaf spots and 

root rot and are associated with plant parts other than fruit. Most of the 51 quarantine 

 7 shipped 29,990 tons of avocados from October 15 to April 15.
 

 Page 18 

arthropods identified feed strictly on leaves and although they may be serious pests, 

they do not normally attack the fruit. The phytosanitary conditions required to satisfy 

existing regulations (e.g., 7 CFR § 319.56) are sufficient to ensure that these pests do 

not accompany shipments of fruit. 

The following five arthropods satisfied both the quarantine and pathway criteria: 

− Conotrachelus aguacatae - seed weevil 

− Conotrachelus perseae - seed weevil 

− Heilipus lauri - seed weevil 

− Copturus aguacatae - stem weevil 

− Stenoma catenifer - seed moth 

These pests are referred to as pathway pests in this risk assessment; we categorized 

them as follows: 

− seed weevils: Conotrachelus aguacatae, C. perseae, Heilipus lauri

− stem weevil: Copturus aguacatae

− seed moth: Stenoma catenifer
 

 Page 19 

Proportion (P1) of Avocados Infested

Initiating Event: Harvest and Packing Fruit in Mexico, for export to the U.S.

Number (N) of Avocados Imported 

per Year

Proportion (P2) of Fruit Reaching 

Avocado Producing Counties

Output (Q2): Annual Number of Infested Avocados Reaching Avocado Producing 

Counties [Q2 = N X P1 X P2]

Output (Q1): Annual Number of Infested Avocados Reaching the U.S. 

[Q1 = N X P1]

Avocados/Year

Infested Avocados

Avocado

Infested Avocados reaching

 avocado growing counties

infested avocado

Pathway Scenario Model 

A quantitative model was developed to estimate the risk of introduction of the five 

pathway pests: seed weevils, (Conotrachelus aguacatae, C. perseae, Heilipus lauri) 

stem weevils, (Copturus aguacatae) and seed moths (Stenoma catenifer). The scenario 

considered is the importation of ‘Hass’ avocados from Michoacán, Mexico and 

distribution to the entire United States during the entire year. The pathway extends 

from harvest and packing in Mexico, through all of the mitigations described in the 

key safeguards section, and terminates with infested avocados distributed to avocadoproducing counties in the United States (Q2, Figure 1). Outputs of this model include 

estimates for the number of infested avocados that will reach the United States (Q1) 

and the number of avocados that will reach avocado producing counties in the United 

States each year (Q2). The model assumes compliance with the mitigations in the 

systems approach (key safeguards section). 

N – Annual Number of Fruit Imported

Between 275 million to 442 million pounds of ‘Hass’ avocados (approximately, 528 

million to 849 million avocados, based on 1.92 avocados per pound) per year will 

likely be imported from Mexico, if they are allowed to enter all states year-round. The 

number imported in 2002 totaled 

about 59 million pounds. Avocado 

imports from Mexico are thus 

expected to increase from four 

to seven times their current 

level. The estimated range of 

imported avocados could 

become 295 million pounds to 

442 million pounds 

(approximately, 567 million to 

849 million avocados) per year 

after five years due to 

population growth. Details of 

the approach used in the 

approximating these ranges 

can be found in Appendix E. 

A uniform distribution from 528 million to 849 million was used as an estimate of the 

number of ‘Hass’ avocados imported from Mexico under the expanded distribution 

scenario. The range used for N was based on the lower end-point approximation at 

present (528 million avocados) and the higher end-point approximation five years 

hence (approximately, 849 million avocados). 

P1 – Proportion of Avocados Infested 

Three sources of data relevant to the proportion of avocados infested were identified. 

First, six years of fruit cutting data for avocados imported to the United States were 

compiled by APHIS (table 4). Second, Japan compiled data on avocado inspections 

Figure 1 – Mexican Hass Avocado Pathway Scenario 
 

 Page 20 

for importation to that country from 1992-1994. Finally, data from foliage surveys for 

pests in Michoacán orchards between 1997 and 2000 were available (Table 5a and 

5b). Only the first source (U.S. fruit cutting data) was used to estimate the proportion 

of avocados infested. The other two data sources were not used in the quantitative 

estimation but the results of all three data sources are consistent. That consistency 

reinforces our belief that the data is accurate. The three data sets are presented and 

discussed below. 

US fruit cutting data 

Mexican and U.S. 

officials inspected 

more than ten 

million avocados 

over the last six 

years and found 

zero infested 

avocados (APHIS, 

2001b; table 4). 

The Work Plan for 

the Exportation of 

‘Hass’ Avocados 

from Mexico to the 

United States of America (USDA, 2001b - Appendix C) details the procedures for 

avocado inspections. The inspectors cut the fruit into slices which are visually 

examined for fruit flies, seed pests, and stem weevils. Fruit are inspected in the 

orchards during harvest, in the packing houses in Mexico, and on arrival in the United 

States. In the packing houses, Mexican inspectors sample the equivalent of 300 fruit 

from each shipment to the United States. Seventy-five fruit are sampled from each 

field truck arriving at the packing house from the orchard. That level of sampling is 

equivalent to sampling 300 fruit from the shipment departing the packing house. 

U.S. DHS inspectors examine 30 avocados selected from 30 boxes on each truck 

arriving at U.S. ports of entry.

The sensitivity of avocado inspection is estimated to be 50%, meaning that an 

inspector would identify 50% of infested, sampled avocados. This estimate is based 

on Gould (1995) who reported that the sensitivity of inspections for Caribbean fruit fly 

larva in grapefruit was 35% and that the sensitivity for starfruit inspections was 80%. 

The ability to detect larva was greater for fruit with uniform, smooth pulp. Avocados 

have uniform, smooth pulp and inspectors can easily find blemishes, pest tunnels, and 

larva. The estimate of 50% is slightly less than the average sensitivity reported for 

starfruit and grapefruit ([35% + 80%] ÷ 2 = 57.5%). This estimate is probably cautious 

(i.e. an underestimate) for four of the five pathway pests because avocados are more 

similar to starfruit than grapefruit in terms of ease of fly detection. 

The sensitivity of avocado inspection may vary somewhat among the five pathway 

Table 4. Fruit sampled for seed weevil, stem weevil, seed moth, and fruit flies* 

Season Field 

Samples 

Packing 

house 

Border 

Inspection 

Row 

Total 

Quarantine 

Pests 

1997/1998 1,155,305 417,900 10,410 1,583,615 None 

1998/1999 1,121,471 203,250 16,860 1,341,581 None 

1999/2000 952,423 166,650 20,070 1,139,143 None 

2000/2001 1,209,814 172,800 17,280 1,399,894 None 

2001/2002 1,616,456 347,475 41,250 2,005,181 None 

2002/2003 2,749,876 141,558 11,880 2,903,314 None 

Subtotal 8,805,345 1,449,633 117,750 10,372,728 None 

*Source: Federal Register Vol. 66, No. 135, p 36896-7 and Secretaria de Agricultura, 

Ganaderia, Desarrollo Rural, Pesca y Alimentacion, Mexico. The table was updated with 

information from the 2001/2002 and 2002/2003 shipping seasons.
 

 Page 21 

pests. All five may damage the fruit pulp as part of feeding if present in the fruit. 

However, the stem weevil (Copturus aguacatae) produces tunnels that are usually 

restricted to a small portion of the fruit close to the stem. Stem weevils, however, 

produce a white exudate on the stems of avocados that is readily visible. The larvae 

only rarely migrate into the fruit and when they do, they are usually localized to the 

area of the fruit near the stem. Stem weevil infestation can best be detected by 

examining the foliage in the orchard. Nonetheless, we believe 50% is a reasonable 

estimate of fruit inspection sensitivity for stem weevils. 
 

 Page 22 

Japanese fruit cutting data 

Table 5a - Foliage Surveys in Avocado Orchards in Michoacán, Mexico 

(Proposed orchards to be included in the Hass avocado export program to the US) 

Number of Orchards Positive 

Year 

Number of 

Orchards 

Stem Weevil 

Copturus 

aguacatae

Seed 

Weevil 

Heilipus 

lauri

Seed Moth 

Stenoma 

catenifer

Seed Weevil 

Conotrachelus 

aguacatae

Seed Weevil 

Contrachelus 

perseae

1997 61 0 0 0 0 0 

1998 244 0 0 0 0 0 

1999 500 3 0 0 0 0 

2000 790 0 0 0 0 0 

2001 996 1 0 0 0 0 

2002 1,469 3 0 0 0 0 

Total 4,060 7 0 0 0 0 

Table 5b – Wild and Backyard Tree Surveys in Michoacán, Mexico 

Number of Sites Positive 

Year No. of 

backyards 

No. of 

wild trees 

surveyed 

Stem 

Weevil 

Copturus 

aguacatae

Seed 

Weevil 

Heilipus 

lauri

Seed 

Moth 

Stenoma 

catenifer

Seed Weevil 

Conotrachelus 

aguacatae

Seed Weevil 

Contrachelus 

perseae

1997 42 200 0 0 0 0 0

1998 107 19 0 0 0 0

1999 31 379 37 0 0 0 0

2000 54 270 25 0 0 0 0

2001 54 191 24 0 0 0 0 

2002 398 762 145 0 0 0 0 

Total 661 1,909 250 0 0 0 0 

Source - U.S. Department of Agriculture, Animal and Plant Health Inspection Service, International Services. 

– NAR, 2003- Uruapan, Mich. 

From 1992 to 1994 Mexico shipped 5,230,114 kg of ‘Hass’ avocados to Japan (about 

14 million fruit). Japanese agricultural officials inspected 16,000 kg (or about 50,000 

fruits) and reported none of the target pests of concern to the United States. This data 

is consistent with findings from the other two sources and increases our confidence in 

the validity of all three data sources. 

Foliage survey data 

Data from orchard surveys is indirect evidence of the proportion of avocados infested 

(Tables 5a and 5b). The current avocado rule requires annual surveillance of 

municipalities approved to export avocados to the United States for four of the five 

pathway pests (Heilipus lauri, Stenoma catenifer, Conotrachelus aguacatae, and 

Contrachelus perseae). The surveys must cover at least 300 hectares in the 

municipality and include randomly selected portions of each registered orchard and 

areas with wild or backyard avocado trees. The surveys include foliage sampling from 

ten trees per hectare and visual inspection of the orchards for symptoms of the stem 

weevil. Foliage samples are collected by beating the lower branches of a tree over a 

white tarpaulin. The foliage and other material that falls onto the tarpaulin are 

examined for the presence of pests. These surveys will detect a pest if it is present in 

at least one percent (confidence level 95%) of the area surveyed. 

The four pests controlled at the level of the municipality (Heilipus lauri, Stenoma 
 

 Page 23 

catenifer, Conotrachelus aguacatae, and Contrachelus perseae) were never found in 

six annual surveys of the municipalities in Michoacán (table 5a and 5b). The fifth 

pathway pest (stem weevil - Copturus aguacatae) was frequently found in orchards 

and other sites during surveys in Michoacán (Table 5a and 5b). However, this pest 

was rarely found in surveys of orchards registered to export to the United States and 

never found in dissected fruit for export. In annual inspections, five orchards were 

positive over the six years that the surveys were conducted. Data from surveys of 

municipalities and orchards were not used in estimating P1 (the proportion of fruit 

infested) because the data is an indirect measure of fruit infestation prevalence. 

However, orchard infestation is a necessary prerequisite for fruit infestation. The 

consistency between the survey and fruit cutting results increases our confidence in 

their validity. Clearly, the orchard surveys do not state that all pests are absent but the 

overall evidence that includes fruit dissection shows that mitigation measures are 

preventing pests from being in fruit for export. 

In estimating the proportion of 

avocados infested, the sampling 

distribution arises from a 

binomial process. The implicit 

assumptions are that: (a) 

avocados are either infested or 

not infested; (b) infested 

avocados are randomly 

distributed throughout 

shipments; and (c) sampling of 

avocados is random. 

In reality, infested avocados are 

probably clustered because fruit 

from an infested orchard would 

likely be together in a shipment. 

Also, sampling in orchards is not 

random because fallen avocados are targeted for inspection. These potential biases are 

acknowledged; however, they increase the likelihood of pest detection, thus reducing 

the likelihood of undetected pest entry. 

Based on the data, the most likely proportion of infested avocados is zero; the 95% 

confidence interval ranges from 0 to 5.25×10-7 (table 8 and figure 2) (for details of the 

calculations see appendix D). 

Of the three sources of data discussed (i.e. orchard surveys, Japanese inspection 

results, and U.S. inspection results), only the U.S. fruit cutting data was used to 

determine the proportion of avocados infested. The foliage survey data and Japanese 

fruit cutting data support the conclusion that the most likely level of infestation is zero. 

Figure 2 

P1, the Distribution for the Proportion of Avocados Infested

0.00E+00 2.00E-07 4.00E-07 6.00E-07 8.00E-07 1.00E-06 1.20E-06 1.40E-06

 P1, the Proportion of Avocados Infested

Likelihood

95% confidence that P1<= 5.25E-07 
 

 Page 24 

Q1 – Annual number of infested avocados reaching the United States

The estimate for the annual number of infested avocados that reach the United States 

(Q1) is the product of the number of avocados imported (N), and the proportion 

infested (P1) or Q1 = N × P1 (Fig. 1). This estimate includes avocados reaching all 

areas, not just locations where suitable hosts occur. 

Monte Carlo simulation of the model using @Risk (Palisade Corporation, Newfield, 

New York ) and Excel(Microsoft Corporation, Redmond, Washington ) resulted in a 

distribution for Q1 (Figure 3). The most likely value for Q1 is zero; the distribution 

indicates 95% confidence that the annual number of infested avocados is less than 364 

avocados (Figure 3 and Table 8). 

P2 – Proportion of fruit that will reach commercial avocado production areas in the 

United States.

Figure 3. 

 Distribution for Q1 , Number Infested 

Avocados Entering USA Annually

0 250 500 750 1000

 Annual number of infested avocados reaching USA 

Likelihood

95% confidence that Q1 <= 364

A susceptible host population must be present for pests to become established. 

Avocados are the only known hosts in the United States for the five pathway pests. 

Although capable of flight, the adult stages of these pests do not travel long distances 

in search of host material. Consequently, U.S. counties with commercial avocado 

production were used to determine the susceptible habitat for the five pests. 

The proportion of fruit that will reach avocado producing areas in the United States 

(P2) depends, in part, on the number of people living in those areas and the number of 

avocados they eat. In 2001 about 12 million people lived in avocado producing 

counties in California, Florida, and Hawaii (Table 6). The average per capita 
 

 Page 25 

consumption of avocados in the United States was 0.67 lbs of avocados/person/year 

(APHIS, 2001c). Avocado consumption is higher in California and other 

southwestern states (4.29 avocados/person/year) (APHIS, 2001c). 

 The proportion of imported avocados 

reaching avocado producing regions 

in the United States (P2) is estimated 

between 4.3% and 30%. The lower 

value (4.3%) was derived using the 

per capita consumption rate of 

avocados in the United States (0.67 

lbs/person/year). The higher value 

(30%) was derived using the per 

capita consumption rate of avocados 

in the Southwest region of the United 

States (4.29 lbs/person/year). For 

details of the calculations see 

Appendix D. 

Figure 4. 

 Distribution for Q2 , Annual Number of Infested

 Avocados Reaching Avocado Producing Counties 

0 70 140 210 280 350

Q2: Annual number of infested avocados reaching avocado producing counties

Likelilhood

95% confidence that Q2 <= 70

Factors other than those discussed above influence the proportion of avocados that 

reach avocados producing regions (P2). The supply in avocado producing regions is 

higher than the rest of the United States and may reduce the number of avocados 

Table 6 – Characteristics of Avocado Producing Counties in 

the United States 

County State Acreage1

 Population2

Orange CA 1,669 2,890,444 

Ventura CA 11,608 770,630 

San Diego CA 22,862 2,862,819 

Riverside CA 6,074 1,635,888 

Santa Barbara CA 7,660 399,543 

San Luis Obispo CA 1,362 250,727 

San Joaquin Valley CA 89 595,324 

Miami-Dade FL 5,900 2,289,683 

Hawaii HI 230 152,083 

Total 57,454 11,847,141 

1

 Source: USDA- National Agriculture Statistics Service and 

California Avocado Commission. 2

 Source: U.S. Census Bureau – 

Estimated 2001 U.S. Population 277,017,622. The total population 

for avocado producing counties represents ca. 4.3% of the total 

U.S. population. 
 

 Page 26 

imported to those regions. On the other hand, counties with commercial avocado 

production underestimate the susceptible habitat for pathway pests because ornamental 

avocado trees and backyard avocados are also susceptible. These and other factors 

increase the uncertainty in the estimate for P2. Consequently, P2 is represented in the 

simulation by a uniform distribution with a minimum value of 4.3% and a maximum 

of 30% (all values between the minimum and maximum are equally likely). 

Q2 – Annual number of infested avocados that reach regions of the United States 

where avocados are grown commercially.

The estimate of Q2 is a product of the number of avocados imported (N), the 

proportion infested (P1), and the proportion of avocado producing counties in the 

United States (P2) or Q2 = N × P1 × P2. 

Monte Carlo simulation of the model using @Risk® resulted in a distribution for Q2 

(Figure 4). The most likely annual number of infested avocados distributed to 

counties with host material is zero; the distribution indicates a 95% level of confidence 

that that number will not exceed 70 (Figure 4). 
 

 Page 27 

Estimates of Consequences of Introduction 

We rated the potential consequences for each pest with respect to five different 

elements. The ranking considers pest potential in the absence of specific risk 

mitigation activities. Criteria for estimating consequences were qualitative. 

Numerical values (0, 1, 2, or 3 points) were assigned to each element to assist in 

categorization. The sum of the five individual ratings provided an estimate of 

potential consequences for each pest. 

We estimated consequences of introduction for each of the pest categories listed in the 

previous section as candidates for further assessment. For each element (see below), 

each pest is assigned a value of high (3 points), medium (2 points), low (1 point), or 

none (0 points) as indicated. 

The lowest possible ranking for consequences is 3; pests with values of 3-6 are not 

considered to represent significant impact, low impact pests have values of 7-9, 

medium impact pests have values of 10-12, and high impact pests have values of 13-

15. 

 

As a general guideline, cumulative rankings of 8 or less are low risk, 9-12 are medium 

risk, and 13-15 are high risk. This index is considered a biological indicator of the 

potential of the pest to establish, spread, and cause economic and environmental 

impact. However, the actual ranking remains a guideline, with primary emphasis given 

to available evidence for the purpose of reaching final conclusions. 

This process of ranking pests and establishing a ranking for consequences is part of 

our guidelines. Whereas, these indices are considered a valuable indicator, the 

emphasis is on the evidence, not on a specific numeric outcome. Evaluation of the 

rankings permits an organized presentation of relevant evidence. Before presentation 

of the potential consequences, the ranking scheme (from current USDA guidelines, 

version 5.02) is reviewed below. The qualitative assessment of the likelihood of 

introduction from the guidelines has been replaced with a quantitative assessment. 

Risk Element 1: Climate/Host Interaction 

When a pest is introduced to a new area it can be expected to behave as it does in its 

native area if host plants are available and climatic conditions are similar to its native 

area. The evaluation will consider ecological zones, interaction between the 

geographic distribution of the pest and geographic distribution of the host. For this 

element, risk values are based on the availability of both host material and suitable 

climate conditions. To rate this risk element, we use the U.S. "Plant Hardiness Zones" 

as described by the U.S. Department of Agriculture (see Figure 2) (Cathey, 1990). 

Risk values were assigned according to the following. Due to the availability of both 

suitable host plants and suitable climate, the pest has potential to establish a breeding 

colony: 

High (3): In four or more plant hardiness zones. 

Medium (2): In two or three plant hardiness zones. 
 

 Page 28 

Low (1): In only a single plant hardiness zone. 

None (0): In none of the plant hardiness zones. 

Risk Element 2: Host range 

The risk posed by a plant pest depends on both its ability to establish a viable 

reproductive population and its potential for causing plant damage. We assumed risk 

is correlated positively with host range. For pathogens, risk is more complex and 

depends on host range, aggressiveness, virulence and pathogenicity. For both 

arthropods and pathogens, we rated risk primarily as a function of host range as 

follows: 

High (3): Pest attacks multiple species within multiple plant families. 

Medium (2): Pest attacks multiple species within a single plant family. 

Low (1): Pest attacks a single species|multiple species in a single genus. 

Risk Element 3: Dispersal Potential 

A pest may disperse after establishment in a new area. Consider the following: 

− reproductive patterns in the pest (e.g., voltinism, reproductive output) 

− innate dispersal capability of the pest 

− whether natural factors (e.g., wind, water, presence of vectors) facilitate 

dispersal 

High (3): Pest has high reproductive potential (e.g., multiple generations or 

cohorts per year, many offspring per reproductive event, high capacity 

of a population for increase, AND individuals are highly mobile (i.e., 

capable of moving long distances C at least 20 km C either under their 

own power, or by being moved by natural forces such as wind, water or 

vectors). 

Medium (2): Pest has either high reproductive potential OR the species is mobile. 

Low (1): Neither high reproductive potential nor highly mobile. 

Risk Element 4: Economic Impact 

Introduced pests are capable of causing a variety of economic impacts. We divide 

these impacts into three categories: 1. Lower yield of the host crop (e.g., by causing 

plant mortality, or by acting as a disease vector); 2. Lower value of the commodity 

(e.g., by increasing costs of production, lowering market price, or a combination); 3. 

Loss of markets (foreign or domestic). 

High (3): Pest causes all three types of impacts. 

Medium (2): Pest causes any two of the above impacts. 

Low (1): Pest causes any one of the above impacts. 

None (0): Pest does not cause any of the above impacts. 

Risk Element 5: Environmental Impact 

The assessment considered the following four elements: 

1. Establishment of the pest is expected to cause significant, direct environmental 

impacts (e.g., ecological disruptions, reduced biodiversity). 

2. Pest is expected to have direct impacts on species listed by Federal or State 

agencies as endangered, threatened, or candidate. An example of a direct 
 

 Page 29 

impact would be feeding on a listed plant. If feeding trials with the pest have 

not been conducted on the listed organism (no direct negative data), a pest will 

be expected to feed on the plant if it feeds on other species within the genus or 

other genera within the family. 

3. Pest is expected to have indirect impacts on species listed by Federal or State 

agencies as endangered, threatened, or candidate species (e.g., by disrupting 

sensitive, critical habitat). 

4. Establishment of the pest would stimulate control programs consisting of toxic 

chemical pesticides, or release of non-indigenous biological control agents. 

High (3): One or more of the above 

Low (1): None of the above (it is assumed that establishment of a nonindigenous pest will usually have an environmental impact). 

Seed weevils 

Climate/host interaction—Seed weevils infest avocado only (CPC, 2001), which has 

tropical or subtropical distribution in hardiness zones 9-10, this factor is thus rated 

medium as per the guidelines above. However, it is noted that the distribution of 

avocados is limited to a few counties in three states: California, Florida and Hawaii 

(National Agric. Statistics Service, http://www.usda.gov/nass/), thus the rating of 

medium may be biased since hardiness zones assume the entire zone is suitable and 

for the case of avocados, they exist only in a small proportion of hardiness zones 9 and 

10. Given this fact, we note that a rating of low may also be considered. 

 

Host range—Seed weevils species infest avocado only (CPC, 2001), thus the rating is 

low. 

Dispersal potential— Seed weevils have long life cycles (60-120 days), 2-3 

generations per year, and adults are long-lived (about 90 days). Females of 

Conotrachelus spp. can lay up to 70 eggs. Adults are sedentary and tend to remain in 

the foliage of the host tree but are capable of flying between orchards (CPC, 2001; 

Garcia, et al, 1998; Teliz, 2000). Larvae are internal and can be transported 

worldwide by man. Because of their sedentary nature, we considered a low rating. 

However, their long life span increases the likelihood of natural and assisted 

movement and that was our reasoning for a final ranking of high for this factor. 

Economic impact—Seed weevils can cause up to 80% yield loss in the export area 

(Garcia, et al., 1998) and are predicted to cause up to 20% yield loss if they become 

established in the PRA area (Evangelou, et al, 1993). Spray programs for adults are 

required if they are detected by surveys (Teliz, 2000). The species are regulated pests 

(APHIS, 2002) and are likely to be quarantined by other countries. This justified a 

rating of “high”. 

Environmental impact— Seed weevils infest only avocado and there are no 

associations with endangered or threatened species. Spray programs will commence 

in commercial avocado-growing areas of the PRA area if an outbreak occurs 

(Evangelou, et al., 1993). The sprays are not expected to have impacts on endangered 
 

 Page 30 

or threatened species beyond those impacts already caused by existing agriculture. 

This factor was thus rated as low. 

Following the guidelines, the overall impact potential for seed weevils was considered 

High. 

Stem weevil 

Climate/host interaction. The stem weevil infests only avocado, which has tropical or 

subtropical distribution in hardiness zones 9-10 in the PRA area (Velez, 1959). This 

factor was rated medium. However, it was noted that the distribution of avocados is 

limited to a few counties in three states: California, Florida and Hawaii (National 

Agric. Statistics Service, http://www.usda.gov/nass/), thus the rating of medium may 

be biased since hardiness zones assume the entire zone is suitable and for the case of 

avocados, they exist only in a small proportion of hardiness zones 9 and 10. Given this 

fact, we note that a rating of low may also be considered. 

Host range—Avocado is the only host for the stem weevil (Velez, 1959). This factor 

was thus rated low. 

Dispersal potential—The life cycle of the stem weevil is long (>150 days) with a 

protracted larval stage (>115 days) which limits the number of generations to 1-2 

annually (Teliz, 2000). Females only lay up to eight eggs (Velez, 1959). Adults are 

capable of short flights, but mostly remain in foliage (Garcia, et al., 1998) within an 

orchard. Larva are internal and the main method of spread is by man. Because of 

their sedentary nature, we considered a low rating. Their long life span increases the 

likelihood of movement and that was our reasoning for a ranking of medium for this 

factor; however, a ranking of low was also considered. 

Economic impact—Sprays are recommended in the export country when the stem 

weevil is detected (Teliz, 2000). A yield loss of 20% is expected if the pest has an 

outbreak in the PRA area (Evangelou, et al., 1993). Given the importance of the 

avocado as an industry, this factor was given the highest rating. 

Environmental impact—The stem weevil infests avocado only. Spray programs will 

begin in commercial avocado-growing areas of the PRA area if an outbreak occurs 

(Evangelou, et al., 1993). The sprays are not expected to have impacts on endangered 

or threatened species beyond those due to existing agricultural practices. This factor 

was thus rated as low. 

Following the guidelines, the overall impact potential for stem weevils was considered 

low to medium. 

We note that the potential economic impacts of weevil infestations in California were 

analyzed in 1993 (Evangelou et al., 1993). They assumed that weevils would colonize 

all of the production areas in California. They further assumed that growers would 

resort to chemical control. The chemical controls would disrupt existing natural 
 

 Page 31 

balances, resulting subsequently in outbreaks of loopers, mites and other pests that 

would require additional treatments. They estimated that annual production costs 

would increase by 41% and avocado yields would decrease by an assumed 20% due to 

limited effectiveness of aerial treatments. They estimated social losses to total $123.6 

million per year. 

Seed moth 

Climate/host interaction—The seed moth may be able to infest Persea borbonia (L.) 

Spreng. (redbay) because avocados and redbay belong to the same genus. However, 

redbay is not a reported host for the seed moth. Redbay occurs along the south 

Atlantic and Gulf coasts (USFS, 2002). The two hosts are distributed in hardiness 

zones 7-9. This factor was thus rated medium; a rating of low was also considered for 

the same reasons cited for the pests above. 

Host range—The seed moth infests species in several genera of Lauraceae, including 

greenheart (Chlocardium rodiei (Schomb.) Rohwer Richter & van der Werff) 

(Cervantes-Peredo, et al., 1999). However, avocado (Persea americana), is the only 

known host in the United States. This factor was thus rated low. 

Dispersal potential—The seed moth occurs widely over the export area, but is limited 

there to avocados grown below 1,000 m elevation (Cervantes-Peredo, 2000). Adults 

can fly and females have high reproductive potential because they can lay up to 240 

eggs (Jaramillo et al., 1972). Up to three generations per year are recorded (Garcia, et 

al., 1998). Because larvae are internal, worldwide spread by man is possible. This 

factor was rated high. 

Economic impact—Fruit of all sizes are infested by seed moth. Fruit that are infested 

when small fall off the tree before reaching harvestable size (Cervantes-Peredo, 2000). 

 Over 80% of the avocados (not Hass variety) in some orchards in Brazil were 

infested, and over 80% of those fell before reaching harvestable size (Ventura, et al., 

1999). In field reports from South America, it was noted that ‘Hass’ avocados are not 

the preferred host for seed moth. None of the ‘Hass’ cultivars were infested, but more 

than 54% of other avocado cultivars received damage (Arellano-Cruz, 1998). 

However, the seed moth is a regulated pest (APHIS, 2002) and it is likely that other 

countries would quarantine this pest if it were to become established. This factor was 

thus rated high. 

Environmental impact—If an outbreak occurs in U.S. avocado orchards, spray 

programs against adults like those described for seed and stem weevils (Evangelou, et 

al., 1993) would begin in commercial avocado growing areas. The spray programs are 

not expected to have impacts on endangered or threatened species beyond those due to 

existing agriculture practices. This factor was thus rated as low. 
 

 Page 32 

Following the guidelines, the overall impact potential for the seed moth was 

considered medium. 

The scores for each of the elements above for each pest are presented in Table 7. The 

potential consequences associated with each pest are estimated by adding together the 

values (one for each element). The table associates rankings to the selected quarantine 

pests, i.e., seed weevils, stem weevils, and seed moth. 

Table 7 - Summary of potential consequences from quarantine pests

Pest Climate/Host 

Interaction

Host 

range

Dispersal 

Potential

Economic 

Impact

Environmental 

Impact

Total

Seed weevils 1-2 1 3 3 1 9-10

Stem weevils 1-2 1 1-2 3 1 7-9

Seed moth 1-2 1 3 3 1 9-10

Note: Descriptions of elements and assignment of values are explained in the text; rankings resulted in 

“medium” consequences for weevils and the seed moth. This ranking did not consider specific 

mitigation practices. 
 

 Page 33 

Discussion 

We believe the most likely 

annual number of avocados 

infested with a pathway pest 

likely to be imported from 

Mexico each year under the 

expanded distribution scenario 

is zero. Based on the fruit cutting data alone (ie, ignoring the results of the area and 

orchard surveys and the risk-reducing effects of every element in the systems 

approach), the quantitative model indicates a 95% level of confidence that the annual 

number of infested avocados likely to reach avocado producing counties in the United 

States is not more than 66 (Table 8). 

Even if 66 infested avocados were imported (or 350 to any area in the United States), 

we believe the likelihood pest establishment and spread is small. Establishment and 

spread would require that a) the pests survive during transportation and storage, b) the 

infested avocados must be discarded in close proximity to host material, c) the pests 

must find mates, d) the pests must successfully avoid predation, e) the adult pests must 

find host material, and f) the climatological and microenvironmental conditions must 

be suitable. We believe the likelihood of each of these steps is low. People generally 

consume the fruit they purchase and dispose of the waste material in a manner (ie, in 

plastic bags that are placed in trashcans and which are ultimately are either landfilled 

or incinerated) that precludes the release of pests into the environment. 

As important as are the results of the quantitative model, we cannot ignore the riskreducing effects of the systems approach. We believe the repeated surveys, 

inspections, and the other requirements of the systems approach reduce risk 

substantially. Our confidence in these surveys and inspections is reinforced, first, by 

repeated site visits by APHIS headquarters personnel; second, by the active 

participation of APHIS field personnel in the surveys; third, by the redundancy of the 

systems approach mitigations; and fourth, by the fact that examination of over ten 

million fruit has not revealed even one pest. 

We believe the rate of avocado pests entering the United States in commercial 

avocados legally imported in compliance with the proposed modified systems 

approach is certainly far lower than the rate in prohibited avocados in passenger 

baggage and and other types of cargo . APHIS-PPQ port of entry interception database 

records (PIN309) indicate that pathway pests are routinely found in avocados (both 

‘Hass’ and other varieties) intercepted at U.S. ports of entry. Between 1985 and 2002, 

over 500 pathway pests were detected in intercepted avocados in baggage and cargo. 

We are not aware of a single outbreak of any of the pathway pests as a result. We 

conclude that prohibited avocados in baggage and cargo pose a greater risk to U.S. 

agriculture than commercial imports of ‘Hass’ avocados from Mexico. 

Table 8 Results – Pathway Scenario Assessment 

Parameter Most 

likely 

95% CI 

P1 – proportion infested (from sampling data) 0 0 - 5.25×10-7

Q1 – Predicted annual number of infested 

avocados 

0 0 to 350 

Q2 – Predicted annual number of infested 

avocados reaching producing counties 

0 0 to 66 
 

 Page 34 

Conclusions 

1. Hass avocados imported from Michoacán, Mexico are a potential pathway for 

only five of the 116 avocado pests known to occur in Mexico. These five include 

three seed weevils: Conotrachelus aguacatae, C. perseae, and Heilipus lauri; one 

stem weevil: Copturus aguacatae; and one seed moth: Stenoma catenifer. 

2. The exporting municipalities in Michoacán have been and are likely to remain 

free of Conotrachelus aguacatae, Heilipus lauri, and Stenoma catenifer and 

Conotrachelus perseae. Repeated area surveys and inspections of orchards and 

processed fruit by Mexican and USDA-APHIS personnel for over six years have 

failed to find these pests. Over ten million fruit were examined for pest larva with 

negative results. 

The remaining pathway pest (stem weevil, Copturus aguacate) is known to exist in 

Michoacán. The pest was detected five times in annual surveys of export-eligible 

orchards over six years. Those orchards were subsequently prohibited to export fruit. 

The pest was never found in exported fruit. 

3. The systems approach is effective. Six years experience, including the 

dissection of over ten million fruit, validates the effectiveness of the systems approach 

in preventing the introduction of Mexican avocado pests. The systems approach for 

avocado imports focuses both on preventing infestation and on detecting infestion if it 

occurs. The systems approach includes redundant safeguards such as surveys, orchard 

inspections, certification, fruit inspection, and trace-back ability. 

4. The most likely annual number of imported infested fruit is zero. The large 

and unprecedented number of avocados inspected allows estimation of the highest 

number of infested avocados that could be imported without detection with a high 

degree of precision. A quantitative model based only on the fruit cutting data predicts 

that the most likely number of imported, infested avocados is zero. Specifically, the 

most likely proportion of infested avocados was found to be zero; the 95% confidence 

interval ranged from 0 to 5.25×10-7 [that is, from 0 to 52.5/100,000,000]. 

5. A probabilistic assessment based on the fruit cutting data and forecast fruit 

exported to the United States found that the annual number of imported fruit infested 

with any pathway pest and distributed to avocado-producing counties per year is most 

likely zero and almost certainly would not exceed 66. Our belief that that the most 

likely number is in fact zero is supported by other evidence such as the annual 

surveys of municipalities and orchards (Table 5a and 5b) and Japanese fruit cutting 

data. 

6. Commercially harvested and processed ‘Hass’ avocados are not hosts for 

Anastrepha fruit flies. In the past, these fruit flies were one of APHIS’s greatest 

concerns. However, recent research (Aluja et al, 2002) indicates that avocados do not 
 

 Page 35 

serve as hosts for Anastrepha spp. This research, conducted under both field and 

laboratory conditions, demonstrated that Anastrepha spp. will not develop in ‘Hass’ 

avocados under commercial field conditions. When ‘Hass’ avocados were the only 

available host, oviposition occured but larvae did not mature. 
 

 Page 36 

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 Page 43 

Preparation, Consultation and Review 

Agency Contacts: 

Ron Sequeira, Ron.A.Sequeira@aphis.usda.gov 

M. Hennessey, L. Millar, T. Kalaris, N. Jones 

A. Hogue, D. Oryang 

This pest risk assessment was prepared by the Center for Plant Health Science and 

technology (CPHST) within Plant Protection and Quarantine (APHIS-USDA), it 

contains material included in previous risk assessments for avocados from Mexico. 

-Previous versions of documents analyzing risks associated with avocados from 

Mexico were developed by: 

M. Firko, J. Lightfield, E. Podleckis, S. Redlin, R. Stewart, D. Odermatt, C. Miller, T. 

Henry, S. Nakahara, and J. Pakaluk. 

Internal Review*: 

R.Fite, C.E.Miller, D. Oryang, R.McDowell, USDA-APHIS-PPD 

*External review is sought by publication of this assessment and requesting 

stakeholder input. 
Appendix A – Pest List 

 Page 44 

Appendix A: Pest List 

Table A-1: Pathogens. 

Scientific Name 1 and Common 

Name 

Distribution 2 Comment 3 References 

Fungi 

Armillaria mellea (Vahl:Fr.) P. 

Kumm. 

Armillaria root rot 

MX CA FL 

OT 

a, c Ploetz, et al., 1994; CMI, 1980a 

Colletotrichum gloeosporioides

(Penz.) Penz. & Sacc. in Penz. 

Teleomorph: Glomerella cingulata

(Stone.) Spauld. & H. Schrenk 

Anthracnose 

MX CA FL HI 

TX OT 

c, f Ploetz, et al., 1994 

Diaporthe rudis (Fr:Fr) Nitschke 

Synonym: Diaporthe medusaea

Nitschke 

Melanose 

MX CA FL 

TX OT 

c, f Kranz, et al., 1977 

Ganoderma lucidum (Curtis:Fr) P. 

Karst. 

Wood rot 

MX CA FL 

TX OT 

a, f Morales-Garcia, 1989; Farr, et al.,

1989; CMI, 1975 

Lasiodiplodia theobromae (Pat.) 

Griffon & Maubl. 

Stem-end rot 

MX CA FL 

 OT 

c, f Alfieri, et al., 1984; CMI, 1976 

Mycosphaerella perseae L.E. 

Miles 

Leaf spot 

MX FL a, f Farr, et al., 1989; Alfieri, et al., 1984 

Phyllachora gratissima Rehm. 

Tar spot 

MX a, x Watson, 1971 

Phymatotrichopsis omnivora

(Duggar) Hennebert 

Texas foot rot 

MX CA 

TX 

a, c, f Morales-Garcia, 1989 

Phytophthora cinnamomi Rands 

Phytophthora root rot 

MX CA FL 

TX OT 

a, f Ploetz, et al., 1994; CMI, 1991 

Phytophthora citricola Sawada 

Black fruit rot 

MX CA 

 OT 

c, f Fucikovsky & Luna, 1987; Ploetz, et 

al., 1994; CMI, 1979 

Phytophthora nicotianae Breda de 

Haan var. parasitica (Dastur) G.M. 

Waterhouse 

Collar rot 

MX CA FL 

 OT 

c, f Alfieri, et al., 1984; Farr, et al., 1989; 

CMI, 1964 

Pseudocercospora purpurea

(Cooke) Deighton 

Synonym: Cercospora purpurea 

Cooke 

Cercospora spot, Blotch 

MX CA FL c, f Fucikovsky & Luna, 1987; Ploetz, et 

al., 1994 

Pythium ultimum Trow 

Root rot 

MX CA FL HI 

 OT 

a, c, f French, 1989; CMI, 1981b 

Rhizoctonia solani Kühn 

Root rot 

MX CA FL 

TX OT 

a, c, f Alfieri, et al., 1984; Farr, et al., 1989; 

French, 1989; CMI, 1974 

Rosellinia bunodes (Berk. & Br.) 

Sacc. 

MX a Ploetz, et al., 1994; Watson, 1971; 

CMI, 1985 
Appendix A – Pest List 

 Page 45 

Table A-1: Pathogens. 

Scientific Name 1 and Common 

Name 

Distribution 2 Comment 3 References 

Black (Rosellinia) root rot 

Rosellinia necatrix Prill. 

Anamorph: Dematophora necatrix

R. Hartig 

White root rot 

MX CA 

 OT 

a, f Ploetz, et al., 1994; CMI, 1987 

Rosellinia pepo Pat. 

Black root rot 

MX a Ploetz, et al., 1994; CMI, 1968 

Sclerotium rolfsii Sacc. 

Anamorph: Corticium rolfsii Curzi 

Seedling blight 

MX CA FL HI 

TX OT 

c, f Alfieri, et al., 1984; CMI, 1981a 

Sphaceloma perseae Jenkins 

Scab, Rona

MX CA FL 

TX 

c, f, x Ploetz, et al., 1994; CMI, 1986a 

Verticillium albo-atrum Reinke & 

Bert. 

Verticillium wilt

MX CA FL 

TX OT 

a, c, f Ploetz, et al., 1994; Morales-Garcia, 

1989; CMI, 1986b 

Bacteria 

Agrobacterium tumefaciens (Smith 

& Town.) Conn 

Crown gall

MX CA FL 

TX OT 

a, c, f Bradbury, 1986; CMI, 1980b 

Erwinia carotovora subsp. 

carotovora (Jones) Bergey et al.

Soft rot

MX CA FL HI 

TX OT 

c, f Bradbury, 1986 

Erwinia herbicola (Löhnis) Dye MX CA FL HI 

TX OT 

f Bradbury, 1986; Fucikovsky & Luna, 

1987 

Pseudomonas syringae pv. 

syringae van Hall 

Fruit spot, Blossom blight, Blast

MX CA FL 

TX OT 

c, f Bradbury, 1986; CMI, 1988 

Nematodes 

Radopholus similis (Cobb) Thorne MX CA FL 

TX OT 

a, f Anonymous, 1984; Ploetz, et al.,

1994; Anonymous, 1992 

Virus, viroid and viruslike agents 

Avocado sunblotch viroid MX CA FL f Fucikovsky & Luna, 1987; Ploetz, et 

al., 1994 

1

 Scientific names of fungi and bacteria as listed in Ploetz, et al., 1994; Bradbury,1986; and Farr, et 

al.,1989. 

2

 Distribution legend: MX = Mexico; CA = California; FL = Florida; HI = Hawaii; TX = Texas; OT = 

Other, occurs in states other than CA, FL, HI, TX. 

3

 Comments: 

a = Pest associated with plant part other than commodity 

c = Listed in U.S. Department of Agriculture (USDA) catalogue of pest interceptions as 

nonactionable 

f = Pest occurs in the United States and is not currently subject to official restrictions and regulations 

(i.e., not listed as actionable or non-actionable, and no official control program) 

x = Multiple interception records exist 
Appendix A – Pest List 

 Page 46 

Table A-2: Arthropods

Genus species Author (Order: Family) Distribution 1 Comments 2 References 

Acanthoscelides sp. (Coleoptera: Bruchidae) MX a Adame, 1998 

Acutaspis albopicta (Cockerell) (Homoptera: 

Diaspididae)

MX, US a, g, j Nakahara, 1982 

Acutaspis perseae (Comstock) (Homoptera: 

Diaspididae) 

MX, US a, j Ebeling, 1959 

Aetalion quadratum Fowler (Homoptera: 

Aetalionidae) 

MX a, g Ebeling, 1959 

Agromyzidae (Diptera), Unidentified species MX a Hennessey, 2002 

Aleurocanthus woglumi Ashby (Homoptera: 

Aleyrodidae) 

MX, US a, g Ballou, 1922; PNKTO 

No.15 

Aleurodicus dugesii (Cockerell) (Homoptera: 

Aleyrodidae) 

MX a, g Ebeling, 1959 

Aleyrodidae (Homoptera) species unidentified MX a Hennessey, 2002 

Amorbia emigratella Busck (Lepidoptera: 

Tortricidae) 

MX, US a, c Ebeling, 1959 

Anthonomus sp. (Coleoptera: Curculionidae) MX a Adame, 1998 

Anastrepha fraterculus (complex) (Diptera 

Tephritidae) 

MX k White, 1988 

Anastrepha ludens (Loew) (Diptera: 

Tephritidae) 

MX, US R, g, w Norrbom & Kim, 1988; 

Stone, 1942; Steck, 1991; 

7 CFR 301.64 

Anastrepha obliqua (Loew) (Diptera: 

Tephritidae) 

MX R, g Norrbom & Kim, 1988; 

Aluja et al. 2002 

Anastrepha serpentina (Wiedemann) (Diptera: 

Tephritidae) 

MX R, g Norrbom & Kim, 1988; 

Aluja et al. 2002 

Anastrepha striata (Diptera: Tephritidae) MX R, g Ballou, 1936; Aluja et al. 

2002 

Apate monacha F. (Coleoptera: Bostrichidae) MX a, g Pierce, 1917 

Aphis gossypii Glover (Homoptera: 

Aphididae) 

MX, US a, c Ebeling, 1959 

Probably Apion sp. (Coleoptera: 

Curculionidae) 

MX a Adame, 1998 

Attelabus sp. (Coleoptera: Curculionidae) MX a Adame, 1998 

Brochymena quadripustulata F.(Heteroptera: 

Pentatomidae) 

MX, US a, c Alvarez et al., 1967; Henry 

& Froeschner, 1988 

Burtinus notatipennis Stal (Heteroptera: 

Coreidae) 

MX, US a, c Ebeling, 1959; Henry & 

Froeschner, 1988 

Capaneus humerosus Distant (Heteroptera: 

Coreidae) 

MX a Ebeling, 1959 

Caulophilus latinasus Say (Coleoptera: 

Curculionidae) 

MX, US a, c McKenzie, 1935 
Appendix A – Pest List 

 Page 47 

Table A-2: Arthropods

Genus species Author (Order: Family) Distribution 1 Comments 2 References 

Ceroplastes cirripediformis Comstock 

(Homoptera: Coccidae) 

MX, US a, c Ebeling, 1959 

Ceroplastes cistudiformis Townsend & 

Cockerell (Homoptera: 

Coccidae) 

MX, US a, c Ebeling, 1959 

Ceroplastes floridensis Comstock 

(Homoptera: Coccidae) 

MX, US a, c Ebeling, 1959 

Ceratitis capitata (Wiedemann) (Diptera: 

Tephritidae) 

MX, US g, l, w, z Metcalf & Metcalf, 1993; 

White & Elson-Harris, 

1992 7 CFR 301.78; 7 

CFR 318.13; 

Chrysomphalus agavis (Townsend & 

Cockerell) (Homoptera:Diaspididae) 

MX, US a, j Ebeling, 1959 

Chrysomphalus aonidum (L) (Homoptera: 

Diaspididae) 

MX, US a, c, j Metcalf & Metcalf, 1993 

Cicadellidae, species unidentified 

(Homoptera)

MX a Hennessey, 2002 

Coccus hesperidum (L) (Homoptera: 

Coccidae) 

MX, US a, c Ebeling, 1959 

Conotrachelus aguacatae Barber (Coleoptera: 

Curculionidae) 

MX z, g Arellano, 1975 

Contrachelus perseae Barber (Coleoptera: 

Curculionidae) 

MX z, g Ebeling, 1959 

Conotrachelus sp. (Coleoptera: Curculionidae) MX z, g Adame, 1998 

Conotrachelus sp. probably flavangulus

Champion 

MX a Adame, 1998 

Possibly Copturomimus sp. (Coleoptera: 

Curculionidae)

MX a Adame, 1998 

Copturus aguacatae (Coleoptera: 

Curculionidae) 

MX z, g MacGregor & Gutierrez, 

1983; PPQ interception 

records 

Copturus constrictus Champion (Coleoptera: 

Curculionidae) 

MX a Sleeper, 1978 

Corthylus nudus Schedl (Coleoptera: 

Scolytidae) 

MX a MacGregor & Gutierrez, 

1983 

Curculionidae unidentified species 

(Coleoptera) 

MX a Adame, 1998 

Probably Cylindrocopturus sp. (Coleoptera: 

Curculionidae)

MX a Adame, 1998 

Deloyala guttata (Olivier) (Coleoptera: 

Chrysomelidae) 

MX a, c Ebeling, 1959 

Diaprepes abbreviatus (L) (Coleoptera: 

Curculionidae) 

MX, US a, g Bennett, 1985 
Appendix A – Pest List 

 Page 48 

Table A-2: Arthropods

Genus species Author (Order: Family) Distribution 1 Comments 2 References 

Dysdercus obliquus (Herrich-Schaeffer) 

(Heteroptera: Pyrrhocoridae) 

MX, US a, c Ebeling, 1959; Henry & 

Froeschner, 1988 

Farinococcus olivaceus (Cockerell) 

(Homoptera:Pseudococcidae) 

Formicidae species undetermined 

(Hymenoptera) 

MX 

MX 

a 

a 

Ebeling, 1959 

Hennessey, 2002 

Frankliniella cephalica (Crawford) 

(Thysanoptera: Thripidae) 

MX, US a, c Ebeling, 1959 

Hansenia pulverulenta (Guerin-Meneville) 

(Homoptera:Flatidae) 

MX a MacGregor & Gutierrez, 

1983 

Heilipus albopictus Champion (Coleoptera: 

Curculionidae) 

MX a MacGregor & Gutierrez, 

1983 

Heilipus lauri Bohemann (Coleoptera: 

Curculionidae) 

MX z, g Ebeling, 1959 

Heliothrips haemorrhoidalis (Bouche) 

(Thysanoptera:Thripidae) 

MX, US a, c Ebeling, 1959 

Hemiberlesia lataniae (Signoret) (Homoptera: 

Diaspididae) 

MX, US a, c, j Nakahara, 1982 

Hemiberlesia rapax (Comstock) (Homoptera: 

Diaspididae) 

MX, US a, c, j Nakahara, 1982 

Icerya montserratensis Riley & Howard 

(Homoptera: Margarodidae) 

MX a, g Ebeling, 1959 

Icerya purchasi Maskell (Homoptera: 

Margarodidae) 

MX, US a, c Ebeling, 1959 

Idona spp. (Homoptera: Cicadellidae) MX, US a Ebeling, 1959 

Largus cinctus Herrich-Schaeffer 

(Heteroptera: Largidae) MX, US a, c Ebeling, 1959; Henry & 

Froeschner, 1988 

Leptoglossus phyllopus (L) Heteroptera: 

Coreidae) 

MX US a, c Ebeling, 1959 

Liothrips perseae (Watson) (Thysanoptera: 

Phlaeothripidae) 

MX a MacGregor & Gutierrez, 

1983; Nakahara, 1995 

Lonchaeidae species undetermined (Diptera) MX a Hennessey, 2002 

Melanaspis aliena (Newstead) (Homoptera: 

Diaspididae) 

MX a, j Nakahara, 1982 

Melipona testacea cupira Smith 

(Hymenoptera: Meliponidae) 

MX a Ebeling, 1959 

Metcalfiella monogramma (Germar) 

(Homoptera: Membracidae) 

MX a, g Ebeling, 1959 

Mycetaspis personata (Comstock) 

(Homoptera: Diaspididae

MX, US a, c, j Nakahara, 1982 

Nipaecoccus nipae (Maskell) (Homoptera: 

Pseudococcidae) 

MX, US a, c Ebeling, 1959 
Appendix A – Pest List 

 Page 49 

Table A-2: Arthropods

Genus species Author (Order: Family) Distribution 1 Comments 2 References 

Oligonychus yothersi (McGregor) (Acarina: 

Tetranychidae) 

MX, US a MacGregor & Gutierrez, 

1983; McMurtry, 1985 

Oligonychus platani (McGregor) (Acarina: 

Tetranychidae) 

MX, US a, c MacGregor & Gutierrez, 

1983; McMurtry, 1985 

Oligonychus punicae (Hirst) (Acarina: 

Tetranychidae) 

MX, US a, c McMurtry, 1985 

Paraleurodes sp. near goyabae (Goeldi) 

(Homoptera: Aleyrodidae) 

MX a Ebeling, 1959 

Planococcus citri (Risso) (Homoptera: 

Pseudococcidae) 

MX, US a, c Ebeling, 1959 

Polydrusus sp. (Coleoptera: Curculionidae) MX a Adame, 1998 

Pseudacysta perseae (Heidemann) 

(Heteroptera: Tingidae) 

MX, US a, c MacGregor & Gutierrez, 

1983; Henry & Froeschner, 

1988 

Pseudobaris sp. (Coleoptera: Curculionidae) MX a Adame, 1998 (USDA 

foliage survey sheet) 

Pseudococcus longispinus (Targioni-Tozzetti) 

(Homoptera: Pseudococcidae) 

MX, US a, c Ebeling, 1959 

Pseudococcidae unidentified species 

(Homoptera) 

MX a Hennessey, 2002 

Psychidae species unidentified (Lepidoptera) MX a Hennessey, 2002 

Pulvinaria simulans Cockerell (Homoptera: 

Coccidae) 

MX a Ebeling, 1959 

Pyrrhopyge chalybea Scudder (Lepidoptera: 

Hesperiidae) 

MX a, g Diaz, 1976 

Rhyssematus sp. (Coleoptera: Curculionidae) 

(unconfirmed)

MX a Adame, 1998 

Saissetia coffeae (Walker) (Homoptera: 

Coccidae) 

MX, US a, c Metcalf & Metcalf, 1993 

Saissetia hemisphaerica (Targioni) 

(Homoptera: Coccidae) 

MX, US a Ebeling, 1959 

Scaphytopius sp. (Homoptera: Cicadellidae) MX a, g Ebeling, 1959 

Stenoma catenifer Walsingham (Lepidoptera: 

Oecophoridae) 

MX z, g Ebeling, 1959 

Trialeurodes similis Russell (Homoptera: 

Aleyrodidae) 

MX a, c Ebeling, 1959 

Trioza anceps Tuthill (Homoptera: Psyllidae) MX a, g MacGregor & Gutierrez, 

1983 

1

 Distribution legend: MX = Mexico; US = United States. 

2

 Comments: 

a = Pest associated with plant part other than commodity. 
Appendix A – Pest List 

 Page 50 

c = Listed in U.S. Department of Agriculture (USDA) catalogue of pest interceptions as nonactionable. 

g = Listed in the USDA catalogue of intercepted pests as actionable. 

j = Armored scale insect: no quarantine action taken on fruit for consumption because "...armored 

scales in general have a low probability of establishment from infested shipments of 

commercial fruit" (ARS, 1985). 

k = The population of this species complex that occurs in Mexico and Central America has never 

been associated with any variety of avocado fruit. 

l = Pest reported to occur in export country but not known to occur in area of production and 

processing. 

R = Revised from previous assessments to: Pests that do not follow the pathway of commercially 

produced ‘Hass’ avocados from Michoacán, Mexico. A review of recent research on 

Anastrepha spp. (Appendix C) concluded that commercially produced ‘Hass’ avocados are 

not hosts for the four species considered (A. serpentina, A. ludens, A. striata, and A. obliqua). 

w = Program pest, occurs in the United States but not widely distributed and being officially 

controlled. 

z = Pest is known to commonly attack or infest fruit and it would be reasonable to expect the pest 

may remain with the fruit during processing and shipping. 
 Page 51 

51

Appendix B: Review of the Biology of Selected Pests 

This review of the biology of selected quarantine pests is an update of information in 

attachments 1 and 2 of the initial pest risk assessment: “Risk Management Assessment: A 

Systems Approach for Mexican Avocados” (APHIS, 1995). Key evidence from those 

documents was revised and updated. 

1. Conotrachelus perseae and C. aguacate (seed weevils) 

a. Distribution -These seed weevils are reported to occur in Mexico and Central American as far 

south as Panama (Whitehead 1979; Ebeling 1959). In Mexico, C. perseae is reported for the 

states of Michoacán, Puebla, Veracruz, and Jalisco: C. aguacate is reported for the states of 

Coahuila. Jalisco, Michoacán, Nayarit, Queretaro, Guanajuato, Puebla, and Morelos 

(Whitehead 1979 and Sanidad Vegetal 1992), and is prevalent at high altitudes. FAO (1986) 

reports its occurrence in Mexico 

b. Host -The only host reported for C. perseae and C. aguacate is P. americana (avocado). 

Interceptions of Conotrachelus by PPQ indicate that the “Creole type of avocado" (Mexican 

race) seems to be most heavily attacked (USDA 1941). Sanidad Vegetal (1992) reports that both 

of these weevils prefer the Mexican race of avocado but also attack the variety ‘Hass.’ Since 

Conotrachelaus is reported as a pest of avocado in Central America, it should be assumed that 

various varieties of the Guatemalan race of avocado could be attacked. 

c. Biology -Eggs are deposited on the young undeveloped fruit and the larva feed in the seed 

until they are fully developed. When fully developed the larva exit the fruit and pupate in the 

soil. Sanidad Vegetal (1992) reports that from one to four larvae of C. perseae develop in each 

infested fruit, however, Sleeper (1978) reports that up to 28 larvae can be found in one fruit. 

Sanidad Vegetal (1992) also states that the damaged fruit falls to the ground before the fruit is 

fully developed and Sleeper (1978) states that infested fruits usually fall to the ground. PPQ has 

intercepted larvae in various stages of development in avocado fruits being smuggled into the 

United States, which would indicate that at least a portion of the infested fruits developed to a 

marketable stage (USDA 1941). The adults are active at night and feed to at least some degree on 

the fruits, leaves, and stems of avocado trees. In Mexico, C. perseae is reported to have two 

generations per year. 

d. Economic Importance -Ebeling (1959) ranked both of these weevils as minor pests of 

avocados. Arellano (1975) reports this pest tunneling in the seeds of P. americana. Sanidad 

Vegetal (1992) reported that on neglected farms the infestation rate could be between 7 and 18 

percent of the fruit and as high as 66 percent from Creole trees. Field controls reported by 

Sanidad Veqetal include fo1iage and ground application of pesticides, raking of the ground to 

expose the pupae, and the collection and destruction of fallen fruit (Sanidad Vegetal 1992). 

2. Heilipus lauri (a seed weevil) 

a. Distribution -This pest is reported to occur from Mexico south to at least Colombia. In 

Mexico, it is reported from the states of Hidalgo, Mexico. Morelos, Veracruz, Guerrero, Puebla 

and Tlaxcala (Garcia 1962: Sanidad Vegetal 1992; MacGregor, 1983). This pest is also reported 

at high altitudes. 

b. Host -Sanidad Vegetal (1992) reports that it prefers Creole avocado tree (Mexican race) but 

also attacks improved avocado varieties. 

c. Biology -Ebe1ing (1959) reports the biology of this pest. He states that there is one generation 

per year. The winter is spent in the adult stage and the adults deposit eggs in the developing fruit 
 Page 52 

52

in May, June, and Ju1y. The larvae tunnel to the seed where they feed and pupate. After the 

adults leave the fruit they feed on the leaf, bud, sprout, and fruit of their host. Sometimes 

pupation takes place in the soil from fallen fruit. Sanidad Vegetal (1992) states that there is an 

average of two larvae per infested seed and that there were two generations in a 15.5-month 

period in Morelos, where this pest was studied. 

d. Economic Importance -Ebeling (1959) ranked this pest as a major pest of avocado; larvae feed 

in seeds, adults on leaves. In certain areas of Mexico, it can cause up to 80 percent fruit loss 

(Garcia 1962). Sanidad Vegetal (1992) reported various field controls including foliar 

application of pesticides directed at the adu1ts, weed control, and destruction of fallen fruit. 

3. Copturus aguacate (an avocado stem weevi1) 

a. Distribution -This weevil is known only from the Mexican States of Guerrero, Puebla, 

Morelos, and Michoacán (Whitehead 1979b, Kissinger 1957; Macgregor, 1983). 

b. Host- The only host reported was P. americana (Kissinger 1957, Muniz 1959). Adults reared 

from smuggled avocado fruit intercepted at the Mexican border were C. aguacate. In recent 

years, larvae have been detected in ‘Hass’ avocado fruit intercepted by PPQ from Mexico, 

mainly at El Paso, Texas. 

c. Biology -The weevil bores into the small new stems and branches, but can affect the older 

branches at high population densities. Eggs are laid in the epidermis of the plant. A maximum of 

eight eggs are laid in a group by the female. Oviposition occurs mostly in April and May by the 

first generation and in October and November by the second generation, a1though adults emerge 

from May to early July and from November to February (Muniz 1959). 

d. Economic Importance -This species and related weevils have been reported to cause great 

destruction to avocado trees. The boring of this pest causes die back of the branches and 

uncontrolled infestations can cause reduction in size of the tree. Ebeling (1959), Sleeper (1978), 

and Whitehead (1979b) call this a major pest. Muniz (1959) states secondary infestions by 

viruses, bacteria and fungi may occur. This and related pests have been controlled by repeated 

foliar applications of contact pesticides. 

4. Stenoma catenifer (avocado seed moth) 

a. Distribution -This pest is reported to occur from Mexico south to Brazil (Acevedo 1973), and 

has recently been reported in Guyana (Cervales Peredo et al. 1999). In Mexico, it is reported 

from the states of Veracruz, Tamaulipas, Oaxaca, Chiapas, Nuevo Leon, Guerrero, and Colima 

(Acevedo 1973; Macgregor, 1983). It is not reported from Michoacán. 

b Host -This moth is reported to attack P. scheidiana (chinini) and Beilschmedia sp. (anayo) 

(Acevedo 1973, USDA 1980). It also attacks P. americana (cultivated avocado), and has been 

reported on the varieties ‘Choquette’, ‘Hall’, ‘Lula’, ‘Booth 7’, ‘Booth 8’, and ‘Carmelita’ 

(Acevedo 1973; Ebeling, 1959). Recently it was reported on Chlorocardium rodiei 

(Greenheart), the most important timber tree in Guyana (Cervantes Peredo et al. 1999). 

c. Biology -This moth spends the winter as an adult in the soil or leaf litter. In the spring the 

female mates and deposits eggs on the stem and fruit of its hosts. Adults usually remain hidden 

during the day and fly erratically around the host at night. The 1arvae bores in the stem and 

fruit. Within the fruit it feeds on the pulp for several days before moving into the seed, where the 

main part of its development takes place. Pupation takes place outside of the fruit, in or on the 

soil. The number of generations per year varies depending on the availability of fruit (Acevedo 

1973, Ebeling 1959, and USDA 1980). 
 Page 53 

53

d. Economic Importance -This is one of the most serious avocado pests in the world. Ebeling 

(1959) rates it as a major pest of avocado. The larvae damage the terminal twigs and can often 

kill young trees. The damage on stems can also result in fruit drop. The damage occurs about one 

month after the fruit forms, and makes the fruit unmarketable (Acevedo 1973). In Venezuela, it 

is considered one of the most important pests of avocado (Boscar and Godoy 1982). In tropical 

areas of Mexico, this pest is a limiting factor of avocado production. A fruit infestation rate of 94 

percent has been reported, and one larva can destroy a fruit. In one study, it required 14 

treatments of pesticide per season to eliminate damage from this pest (Acevedo 1973). 

This section on the review of the biology of selected pests was drafted by C. E. Miller, RAS, 

PPD, APHIS, September 1992 and updated by L. Duffie, USDA-APHIS-PPQ-CPHST, January 

2003. References for this section may be found in the section, “References”. 
 Page 54 

54

Appendix C: Review of Anastrepha Species 

Previous assessment and much of the focus from stakeholders in the past (as per the 

Administrative Record on comments regarding proposed rules for avocado importation from 

Mexico) was on the potential of introduction of Anastrepha spp. fruit flies with ‘Hass’ avocados. 

 The status of ‘Hass’ avocados as hosts of Anastrepha spp. fruit flies has been the focus of 

intense research. From 1992 to 1994 Martinez et al. (1993) dissected 153.5 tons of avocado fruit 

(618,975 fruit) by slicing randomly selected fruit from nine packinghouses into one cm slices. 

No fruit flies were detected as infesting avocados even though trapping data showed that fruit 

flies were present in the area attacking other hosts. In a related study, Enkerlin et al. (1993) 

evaluated the host status of ‘Hass’ avocados before and after removal from the tree. They found 

that Hass avocados were not naturally infested while attached to the tree. Further, when fruit that 

was still attached, was artificially exposed to fruit flies, oviposition did occur but larvae did not 

develop. Enkerlin et al. (1993) report that biochemical processes are likely responsible for the 

lack of viability of eggs in fruit that is attached to the tree. However, this resistance rapidly 

disappeared after harvest. Enkerlin et al. (1993) were able to obtain viable larvae under 

laboratory conditions with artificial infestations of harvested fruit if the fruit was mature (more 

than 21.5% dry matter) and at least 3 hours elapsed after harvest. 

Recent research by Aluja et al. (2002) combined detailed field observations and laboratory 

studies. Field studies were conducted in 2001 and 2002 at 3 different altitudes (1200-1440, 

1600-1800, and 2000-2100 m above sea level) that encompassed all key production areas in the 

state of Michoacán, Mexico. In the field experiments, ready-to-harvest fruit of “Hass” 

avocados collected randomly from six orchards at the three different representative altitudes 

(N=76,941 fruit) did not reveal fruit fly infestations. Additionally, field cages were used to 

artificially infest avocado branches in commercial orchards with large numbers of viable fruit 

flies (wild and lab reared flies). Fruit flies did not infest avocados in any but two instances (two 

fruit). The two fruit that were found infested with fruit flies were held but viable offspring did 

not result (that is, underweight pupae were formed but adults did not emerge). Finally, for the 

field observations, mature avocados were placed on trays on the orchard floor (N=3600 fruit). 

Three fruit were infested by the loncheid decomposer, Neosilba batesi (Diptera: Lonchaeidae), 

but had no fruit fly infestations. This finding further supports the low likelihood of infestation 

by Anastrepha even in fallen fruit. Anastrepha fruit flies have complex host search behaviors 

and do not forage on the ground, as was shown in these studies. 

As part of the observations by Aluja et al. (2002), fruit was sampled from packinghouses 

(N=8,100 fruit) and no infestation was detected. In laboratory trials, fruit was artificially 

exposed to large numbers of fertile pairs of four different species of Anastrepha: A. serpentina, 

A. ludens, A. striata, and A. obliqua. The conditions of exposure varied from “choice” studies 

and “no-choice” studies in laboratory conditions. The no-choice studies included ‘Hass’ 

avocados only. The choice studies included ‘Hass’ avocados and known hosts. Whereas 

oviposition was attempted, infestation by the different fruit flies did not occur. In the choice 

trials, the known hosts were visited more frequently and had infestations that resulted in viable 

offspring. Observations on the physiological responses to oviposition in ‘Hass’ cultivar 

avocados suggest epicarp regeneration and callus formation that inhibits proper larval 
 Page 55 

55

development. The latter observations on the likely resistance mechanisms in avocados by Aluja 

et al. (2002) are consistent with observations by Smith (1973), Armstrong et al. (1993), Martinez 

et al. (1993) and Enkerlin et al. (1993). 

From the above studies and from the rigor of the most recent study by Aluja et al. (2002) (all 

observations and design phases were overseen by USDA and independent reviewers) we 

conclude that commercially produced fruit from Michoacán, Mexico are not a host for the 

Anastrepha spp. considered. Previous assessments (APHIS, 1995a) included Anastrepha spp. as 

part of the quarantine pests that were considered in greater detail although avocados were 

considered non-hosts or at best, poor hosts. However, those earlier assessments concluded that 

there was a very low probability of association of Anastrepha with the ‘Hass’ avocado imports 

(Pest risk assessment, addendum and review 1995a, 1996, 2001). 
 Page 56 

Appendix D - Quantitative Risk Assessment Model 

Summary 

In 1993, APHIS authorized entry of Mexican avocado fruit into Alaska. In 1997 ‘Hass’ avocados 

were allowed to be shipped, from Michoacán, Mexico, to 19 states and the District of Columbia, 

and the allowable shipping season was November 15 to February 15. Since November 2001 

(according to CFR §319.56-2ff: “Administrative instructions governing movement of ‘Hass’ 

avocados from Michoacán, Mexico, to approved States”), ‘Hass’ avocados have been allowed to 

be shipped to 31 states and the District of Columbia, and the allowable shipping season is 

October 15 to April 15. 

This assessment responds to the request to expand the importation of fresh Hass variety avocado 

fruits (Persea americana) grown in the state of Michoacán, Mexico, into all states during all 

months of the year. 

APHIS conducted a screening assessment on one hundred and sixteen (116) previously identified 

avocado pests known to occur in Mexico that may have potential economic importance in the 

United States. The screening involved the elimination of non-quarantine pests and non-pathway 

pests from the list, and resulted in the identification of five pathway pests of quarantine 

significance. These five include: 

1. three seed weevils: Conotrachelus aguacatae, Conotrachelus perseae, and Heilipus lauri; 

2. one stem weevil: Copturus aguacatae; and 

3. one seed moth: Stenoma catenifer. 

Since 1997 approximately 300 million ‘Hass’ avocados have been imported from Mexico under 

a systems management protocol that includes packing house and port of exit/entry inspections. 

To date, more than ten million fruit have been cut and inspected as part of the avocado export 

program, and no quarantine pests have been detected. 

The proposed expanded avocado importation program will involve all States, including avocado 

growing states. 

This risk assessment estimates the annual number of infested avocados entering the United 

States, and the annual number of infested avocados entering counties in the United States 

where avocados are grown. 

This assessment does not evaluate the individual effectiveness of the systems mitigations in reducing 

the phytosanitary risks to the United States. 

 

This assessment utilizes the results of six years of surveys to estimate the proportion of imported 

avocados that are infested. It then estimates: 1) The annual number of infested fruit likely to 

enter the United States by computing the product of the annual number of avocados likely to be 

imported, and the proportion of imported avocados that are infested; 2) The annual number of 

infested fruit likely to enter avocado growing counties in the United States by computing the 

product of the annual number of infested fruit likely to enter the United States, and the 

proportion of avocados consumed in avocado growing counties. 
 Page 57 

APHIS has developed a risk assessment model that is presented in this document. The risk 

assessment predicts that 528 million to 849 million ‘Hass’ avocados will be imported annually from 

Mexico. 

Following is a summary of the results of conducting ten thousand MonteCarlo iterations of the 

risk assessment model using @Risk (Palisade Corporation, Newfield, New York) and Excel 

(Microsoft Inc., Redmond, Washington ). 

 95th percentile Most 

Likely 

Proportion of Mexican avocados that will be infested 

with a pathway pest 

< 

52.5/100,000,000 0 

Proportion of infested avocados that will reach avocado 

producing areas in the United States < 11/100,000,000 0 

Number of avocados, infested with a pathway pest, that 

will enter the United States each year < 350 0 

Number of infested avocados that will reach avocado 

producing areas in the United States < 66 0 

This document presents the methodology and results of the quantitative assessment. 
 Page 58 

METHODOLOGY

The study is comprised of an assessment of the pathway of commercial exports from Mexico of 

fresh ‘Hass’ avocados, produced and imported in compliance with USDA regulations. The 

Quantitative Risk Assessment (QRA) was conducted to identify what can go wrong and how 

likely it is to happen. 

The risk assessment provides a method for evaluating phytosanitary risk and providing 

information to facilitate or support decision-making tasks. 

Based on the probabilistic scenario assessment methodology, the risk assessment process 

involved: 

A. Identifying the phytosanitary hazards; 

B. Stating the questions to be answered; 

C. Developing scenario trees (conceptual outlines), labeling the scenario trees and assigning units; 

D. Stating assumptions; 

E. Gathering and documenting the evidence, and Assigning values to the branches of the scenario 

trees; 

F. Performing calculations to summarize the likelihood of the hazards occurring 

A. Phytosanitary Hazards

APHIS conducted a screening assessment on one hundred and sixteen (116) previously identified 

avocado pests known to occur in Mexico that may have potential economic importance in the 

United States. The screening involved the elimination of non-quarantine pests and non-pathway 

pests from the list of 116, and resulted in the identification of five pathway pests of quarantine 

significance. APHIS has identified the following five quarantine pests that could pose a threat to 

U.S.agriculture if introduced into avocado growing counties in the United States via this 

importation: 

1. seed weevils: 

a. Conotrachelus aguacatae, 

b. Conotrachelus perseae, and 

c. Heilipus lauri

2. stem weevil: Copturus aguacatae

3. seed moth: Stenoma catenifer

The phytosanitary hazard (or unwanted event) is the introduction (entry and establishment) of 

any one of these pests into avocado growing counties in the United States. 

B. Questions to be answered

A quantitative risk assessment usually answers the questions: “What is the likelihood of the 

hazard occurring, what is its magnitude/frequency, and what are the consequences?” This risk 

assessment estimates the likelihood of introduction of any pathway pest into avocado growing 

counties in the US. However, because of lack of quantitative data, the end point of introduction 

(involving entry and establishment), was quantitatively terminated at entry. Therefore, the 

quantitative risk assessment estimates the likelihood of entry of the five avocado pests into 

avocado growing counties in the US. We estimate two quantitative endpoints: a) the number of 

infested avocados reaching the United States each year and b) the number of infested avocados 
 Page 59 

reaching avocado producing regions in the United States each year. 

Due to the lack of quantitative data, the additional steps leading to the establishment of a pest in 

the United States are evaluated using qualitative evidence. 

This quantitative risk assessment answers the following specific questions: 

1. What proportion of the ‘Hass’ avocados entering the United States is infested? 

2. What proportion of imported ‘Hass’ avocados arriving at avocado growing counties 

in the United States? 

3. How many infested ‘Hass’ avocados will enter the United States annually? 

4. How many infested avocados enter avocado growing counties in the United States on 

an annual basis? 

C. Scenario Tree

This risk assessment estimates: 

1. the annual number of infested avocados entering the United States, and 

2. the annual number of infested avocados entering avocado growing counties in the 

United States. 

A scenario tree is a pictorial representation of all possible outcomes of an initiating event. A risk 

pathway tree depicts that subset of pathways that lead to manifestion of a hazard. The risk 

pathway tree is a pictorial representation of what could go wrong in order for infested ‘Hass’ 

avocados from Mexico to reach avocado producing counties in the US. 

Infested ‘Hass’ avocados from Mexico could reach avocado producing counties in the United 

States if: 

A. A quantity of avocados are harvested in Mexico for export to the US, and 

B. a proportion of them are still infested after systems mitigations, and 

C. some infested avocados are distributed to avocado growing counties. 

The annual number of infested avocados entering avocado growing counties in the United States 

is based on: 

 a) N, the potential quantity of avocados to be imported from Mexico, and 

 b) P1, the pest infestation rate (as determined by survey/inspection), and 

 c) P2, the fraction of 

avocados likely to end up in 

avocado growing counties in 

the US. 

A scenario tree describing the 

risk pathway is presented below 

in figure 1. 

D. Quantitative Model 

Assumptions:

The following assumptions 

were made in the quantitative 

model: 

Proportion (P1) of Avocados Infested

Initiating Event: Harvest and Packing Fruit in Mexico, for export to the U.S.

Number (N) of Avocados Imported 

per Year

Proportion (P2) of Fruit Reaching 

Avocado Producing Counties

Output (Q2): Annual Number of Infested Avocados Reaching Avocado Producing 

Counties [Q2 = N X P1 X P2]

Output (Q1): Annual Number of Infested Avocados Reaching the U.S. 

[Q1 = N X P1]

Avocados/Year

Infested Avocados

Avocado

Infested Avocados reaching

 avocado growing counties

infested avocado
 Page 60 

1. Infested avocados are distributed homogeneously throughout the avocado population. 

In other words, each avocado is equally likely to be infested. The probability that any 

given avocado is infested is defined stochastically by a probability distribution. 

2. The process of survey/inspection is a binomial process. 

3. The proportion of avocados reaching avocado production areas in the United States 

was estimated from the proportion of the total U.S.population represented in those 

counties, and the relative per-capita avocado consumption of individuals in those 

counties. 

4. The effectiveness of specific mitigations is not considered in this quantitative model. 

However, it is assumed that the mitigations described in the keys safeguards sections 

will remain in place. 

The evidence used, and manner of estimation of each of the parameters is presented below. 

Parameter Estimates

Parameter Estimate Node 1: Parameter: N

Description: Annual number of Haas avocado imported from Mexico. 

Units: 

Avocados 

-------------------- 

Year

Evidence on N: 

Historical records of Hass avocado importations from Mexico are documented by APHIS in the 

Federal Register (Vol. 66, No. 135, p 36896-7), and summarized in table 1. 

Table 1. Estimated number of Mexican ‘Hass’ avocado fruit entering the United States* 

Season Shipments Boxes Fruit 

1997/1998 347 537,850 25,816,800 

1998/1999 560 868,000 41,664,000 

1999/2000 669 1,036,950 49,773,600 

2000/2001 576 895,900 42,854,400 

2001/2002 - - 101,596,348 

*Source: Federal Register Vol. 66, No. 135, p 36896-7; 

2001/2002 values from J. G. Vila (USDA-APHIS-PPQ) 

1. In 1997 ‘Hass’ avocados were allowed to be shipped, from Michoacán, Mexico, to 19 states 

and the District of Columbia, and the allowable shipping season was November 15 to 

February 15. 
 Page 61 

2. Since November 2001, ‘Hass’ avocados have been allowed to be shipped to 31 states and the 

District of Columbia, and the allowable shipping season is October 15 to April 15 

(7CFR§319.56-2ff) 

3. It is currently proposed that avocados be allowed into all 50 states, with no seasonal 

restrictions. 

Evaluation: 

APHIS believes that the amount of avocados to be imported from Mexico will increase at least 

proportionately to: 

a) the increased number of states that imports are allowed into (50 vs 31), and 

b) the increased time frame in which importation will occur (October to October vs October to 

April) 

c) the future increase in the U.S.population, and specifically of avocado consuming people in the 

US. 

d) the increased market share that Mexican ‘Hass’ avocados will have in the US. 

APHIS estimates that between 528 million and 849 million ‘Hass’ avocados7 will be imported from 

Mexico annually under the expanded distribution scheme. This estimate is based on an economic 

assessment of the potential quantity of imported ‘Hass’ avocados from Mexico (Appendix E). This 

estimate is five to seven times the amount imported in the 2001/2002 season. 

A uniform distribution was used for the annual number of avocados imported from Mexico, and is 

represented by the following equation: 

 N = RiskUniform(528 million , 849 million) 

This uniform distribution is presented in Figure 2. 

N = RiskUniform(528 million , 849 million) 

Figure 2. Uniform distribution for the annual number of ‘Hass’ avocados imported into the US 
 Page 62 

Distribution for N - Number of Fruit Imported Per Year

X <=544018688

5%

X <=832585088

95%

500 600 700 800 900

Number fruit imported from Mexico, millions

Likelihood

Parameter Estimate Node 2: Parameter: P1

Description: Fraction/Proportion of Avocados reaching the UNITED STATES Infested. 

 

Units: 

Infested Avocados 

------------------------------------------------------------------------------ 

Avocado

Evidence on P1: 

P1-1. APHIS has conducted a specific review of the program to allow the importation of 

Mexican Hass avocados. The review identified the following five quarantine pests that 

could pose a threat to US agriculture 

a. seed weevils: Conotrachelus aguacatae, Conotrachelus perseae, and 

Heilipus lauri

b. stem weevil: Copturus aguacatae

c. seed moth: Stenoma catenifer

These pests are evaluated in this risk assessment. 

P1-2. Seed weevils (Conotrachelus aguacatae, Conotrachelus perseae, and Heilipus lauri) and 

seed moths (Stenoma catenifer) have never been found in foliage and tree surveys in 

Michoacan, Mexico. In four years of surveys, the only pest detected via survey in 

Michoacan, Mexico is the stem weevil (Copturus aguacatae). Tables 2 & 3 contain data 

obtained from surveys in Michoacan, Mexico 
 Page 63 

P1-3. None of the orchards that were positive for Stem Weevil were permitted to export 

avocados to the US. They were removed from the export program for the shipping 

season. (7CFR§319.56-2ff(e)(2) p. 331) 

P1-4. To date, more than ten million fruit have been cut as part of the avocado export 

program, and none of the five quarantine pests have been detected as follows in Table 

4. 

P1-5. Table 4. Fruit sampled for seed weevil, stem weevil, seed moth, and fruit flies* 

Season Field 

Samples 

Packing 

house 

Border 

Inspection 

Season 

Total 

Quarantine

Pests 

1997/1998 1,155,305 417,900 10,410 1,583,615 None 

1998/1999 1,121,471 203,250 16,860 1,341,581 None 

1999/2000 952,423 166,650 20,070 1,139,143 None 

2000/2001 1,209,814 172,800 17,280 1,399,894 None 

2001/2002 1,616,456 347,475 41,250 2,005,181 None 

2002/2003 2,749,876 141,558 11,880 2,903,314 None 

Subtotal 8,805,345 1,449,633 117,750 10,372,728 None 

*Source: Federal Register Vol. 66, No. 135, p 36896-7 and Secretaria de Agricultura, Ganaderia, 

Desarrollo Rural, Pesca y Alimentacion, Mexico. The table was update with numbers from the 

2001/2002 and 2002/2003 shipping seasons. 

Table 2 - Foliage Surveys in Avocado Orchards in Michoacán, Mexico 

(Proposed orchards to be included in the Hass avocado export program to the US) 

Number of Orchards Positive 

Year 

Number 

of 

Orchards 

Stem Weevil 

Copturus 

aguacatae

Seed 

Weevil 

Heilipus 

lauri

Seed Moth 

Stenoma 

catenifer

Seed Weevil 

Conotrachelus 

aguacatae

Seed Weevil 

Contrachelus 

perseae

1997 61 0 0 0 0 0 

1998 244 0 0 0 0 0 

1999 500 3 0 0 0 0 

2000 790 0 0 0 0 0 

2001 996 1 0 0 0 0 

2002 1,469 3 0 0 0 0 

Total 4,060 7 0 0 0 0 

Table 3 – Wild and Backyard Tree Surveys in Michoacán, Mexico

Number of Sites Positive 

Year No. of 

backyards 

No. of 

wild 

trees 

surveyed 

Stem 

Weevil 

Copturus 

aguacatae

Seed 

Weevil 

Heilipus 

lauri

Seed 

Moth 

Stenoma 

catenifer

Seed Weevil 

Conotrachelus 

aguacatae

Seed Weevil 

Contrachelus 

perseae

1997 42 200 0 0 0 0 0

1998 107 19 0 0 0 0

1999 31 379 37 0 0 0 0

2000 54 270 25 0 0 0 0

2001 54 191 24 0 0 0 0 

2002 398 762 145 0 0 0 0 

Total 661 1,909 250 0 0 0 0 

Source - U.S. Department of Agriculture, Animal and Plant Health Inspection Service, International 

Services. – NAR, 2003- Uruapan,Mich. 
 Page 64 

Evaluation: 

Examination of the survey data presented in tables 2 & 3 can lead one to conclude that seed weevils 

and seed moths do not exist in Michoacan, Mexico. However, APHIS is uncertain whether the lack 

of detection of these pests is due to pest absence, or is due to below-detectable-levels of pest 

prevalence. For purposes of this risk assessment, APHIS has assumed the latter. 

According to evidence P1-3, none of the orchards that were positive for Stem Weevil (Figure 2 & 3) 

were permitted to export avocados to the US. They were removed from the export program. The 

orchards that remained in the export program have been assumed to have stem weevils at belowdetectable-levels of prevalence. 

Examination of the sampling data for the six import seasons, in Table 4, indicates that a total of 

10,372,728 avocado were sampled, and no quarantine pests were found. 

 

The goal is to estimate the undetectable prevalence of pest infestation in the avocados that are 

imported into the United States. 

The sampling data has been translated into the language of probability as follows: 

• The sampling procedure is modeled as a binomial process where: 

o an avocado is either infested, or not infested, and 

o an infested avocado, when sampled and cut, is determined to be either infested or not 

infested. Sensitivity is a measure of how likely an infested avocado will be positively 

identified. 

o This likelihood of successful identification is the product of the prevalence of 

infestation and the sensitivity of the test, and does not change from trial to trial. 

• The three parameters that characterize a binomial process are: 

o n, the number of trials 

o p, the probability of success on one trial 

o x, the number of successes in n trials 

• Based on the sampling data (Table 4) the values of these three parameters are: 

o n, number of binomial trials, is 10,372,728 

o x, the number of successful trials (detections), is 0 

o p, the probability of success on one trial, x, is unknown. This probability of success 

is the product of the prevalence and the sensitivity. It is what we desire to estimate. 

• When n and x are known, as is the case in hand, the question that can be answered is: 

 What is the probability of success on a single trial if there have been x 

detections in n observations? 

• The RiskBeta @Risk function can be used iteratively to develop a 

Beta probability distribution for the probability of success, p, as 

follows: 

 p = RiskBeta(x+1, n-x+1) 

. 

Because n is greater 7,000,000 the RiskBeta function in @Risk doesn’t work. As a workaround we 

have made a transformation in the sample size, n as follows:
 Page 65 

When the sensitivity of inspection is 100%, one needs half the sample size as one needs when the 

sensitivity is 50% to detect a given prevalence of infestation. 

Therefore, sampling 10,372,728 avocados with a 50% sensitivity of inspection is equivalent to 

sampling 5186364 avocados with 100% sensitivity of inspection. This sample size works with the 

RiskBeta function. 

APHIS has used the @Risk, RiskBeta function to generate the probability distribution for the 

proportion of infested avocados, P1. P1 is represented by the equation: 

 P1 = RiskBeta(x+1, n-x+1), where x =0 and n = 5186364 

The resulting distribution is represented as follows: 

P1, the Distribution for the Proportion of Avocados Infested

0.00E+00 2.00E-07 4.00E-07 6.00E-07 8.00E-07 1.00E-06 1.20E-06 1.40E-06

 P1, the Proportion of Avocados Infested

Likelihood

95% confidence that P1<= 5.25E-07 

There is a 95% confidence that the proportion of infested avocados is less or equal to 5.25x10-7. 

The most likely proportion of infested avocados is zero (0). 
 Page 66 

Parameter Estimate Node 3: Parameter: P2

Description: Proportion of Infested Avocados reaching the United States that end up in a 

susceptible county. 

Units: 

Infested Avocados reaching susceptible counties 

------------------------------------------------------------------------------ 

Infested Avocado 

Evidence: 

P2-1. Table 6 summarizes information about the acreage, yield, and human population of 

avocado producing counties. 

Table 6. Some characteristics of key avocado production areas in the United States 

County State Acreage 

(1) 

Production (1) 

(Mil. Lbs) 

Population 

(2) 

Orange CA 1,669 16.0 2,890,444 

Ventura CA 11,608 99.9 770,630 

San Diego CA 22,862 190.6 2,862,819 

Riverside CA 6,074 41.1 1,635,888 

Santa Barbara CA 7,660 54.2 399,543 

San Luis Obispo CA 1,362 8.9 250,727 

San Joaquin Valley CA 89 2.1 595,324 

Miami-Dade FL 5,900 23.0 2,289,683 

Hawaii HI 230 0.3 152,083 

Total 57,454 436.0 11,847,141 

1/Source: USDA-National Agriculture Statistics Service and California Avocado Commission 

2/Source: U.S.Census Bureau 

P2-2. The U.S. population in 2001 was 277,017,622 people (US Census Bureau) 

P2-3. The percapita consumption of avocados in the southwest of the US, and the whole 

country, are presented in table 7. 

 Table 7. Attributes of the Southeast United States compared to the whole US. 

Region Percapita 

consumption

Population Total 

Pounds 

consumed 

Proportion of National 

pounds consumed 

(Lbs consumed by region, 

divided by Lbs consumed 

by whole country) 

South West 4.29 11,847,141 50,824,235 0.27 

Rest of Country 0.51 265,170,481 135,236,945 0.73 

Whole Country 0.67 277,017,622 186,061,180 1.00 
 Page 67 

P2 Evidence Evaluation: 

In this risk assessment an assumption has been made that the distribution of avocados in the United 

States depends solely on the relative consumption of avocados, and other market forces are not 

considered. 

If the per-capita consumption of avocados were uniform throughout the US, then the proportion of 

infested fruit from Mexico that gets to avocado producing counties would be directly proportional to 

the fraction of the U.S.population represented in those counties. 

The fraction of the U.S.population in avocado growing counties is estimated to be 4.3% [by taking 

the ratio of the total population in avocado growing counties (11,847,141 from column 5 of Table 5), 

and the total U.S.population (277,017,622 from evidence P2-2)]. 

Because the percapita consumption of avocados in the avocado growing counties of the United 

States is greater than the national percapita consumption (Table 7), the proportion of infested fruit 

from Mexico that could potentially get to avocado producing counties is greater than 4.3%. 

Based on the percapita consumptions from column 2 of Table 7, APHIS has estimated that the 

avocado growing counties of the southwest consume 27% of all the avocados in the U.S.market. 

APHIS estimates that other unconsidered market forces could increase this amount by as much as 

10%. This implies that the maximum value for the proportion of avocados going to avocado growing 

counties could be as high as 110% of 27%, which is 29.7%. 

P2, is represent by a uniform distribution that has a minimum value of 4.3% and a maximum value 

of 30% in order to adequately represent the uncertainty about the estimate. 
 Page 68 

The resulting probability distribution function (PDF) for P2 is presented below. 

 Distribution for P2 - Proportion of Infested fruit reaching 

Avocado Producing counties/G59

M ean = 0.1715

X <=0.06

5%

X <=0.29

95%

0 0.1 0.2 0.3 0.4

 Proportion of Infested fruit reaching Avocado growing counties

 Likelihood

Also presented is the cumulative distribution function (CDF) for P2 

 Distribution for P2 - Proportion of Infested fruit reaching 

Avocado Producing counties/G59

M ean = 0.1715

X <=0.29

95%

X <=0.06

5%

0

0.2

0.4

0.6

0.8

1

0 0.1 0.2 0.3 0.4

 P2, Proportion of infested fruit

 Confidence
 Page 69 

F. Mathematical Model: Performing Calculations 

This quantitative risk assessment estimates the number of infested Mexican ‘Hass’ avocados that 

enter avocado growing counties in the US, via the importation of avocados from Michoacán, 

Mexico. 

The annual number of infested avocados entering susceptible counties in the United States is 

based on: 

 a) N, the quantity of avocados imported from Mexico per year, and 

 b) P1, the proportion of avocados that are still infested on importation to the United States 

(the pest infestation rate, as determined by inspection), and 

 c) P2, the fraction of avocados likely to end up in avocado growing counties in the US 

 

As shown in the scenario tree, the annual number of infested avocados entering avocado growing 

counties in the US, Q2, is determined mathematically by taking the product of N, P1 and P2, as 

follows: 

Q2 = N × P1× P2

A dimensional assessment (Also shown in the scenario tree) yields the following units: 

Infested Avocado

Infested Avocados reaching Avocado growing counties

Avocado

Infested Avocados

Year

Avocados Q __ _ _ _ _ _ 2 = × ×

Therefore: 

Year

Infested Avocados reaching Avocado growing counties Q _ _ _ _ _ 2 =

Each of the parameters N, P1, and P2 are 

defined by probability distributions that 

describe a range of possible values and their 

likelihood of occurrence. 

In order to implement the multiplication of 

these distributions, APHIS has used the 

Monte Carlo simulation abilities of the 

@RISK (Palisade Corporation, Newfield, 

New York) software to run 10,000 iterations 

of this model. 

Proportion (P1) of Avocados Infested

Initiating Event: Harvest and Packing Fruit in Mexico, for export to the U.S.

Number (N) of Avocados Imported 

per Year

Proportion (P2) of Fruit Reaching 

Avocado Producing Counties

Output (Q2): Annual Number of Infested Avocados Reaching Avocado Producing 

Counties [Q2 = N X P1 X P2]

Output (Q1): Annual Number of Infested Avocados Reaching the U.S. 

[Q1 = N X P1]

Avocados/Year

Infested Avocados

Avocado

Infested Avocados reaching

 avocado growing counties

infested avocado
 Page 70 

G. Results

APHIS estimates that between 528 million to 849 million ‘Hass’ avocados will be imported each year from 

Mexico. Following is a summary of the results of conducting the ten thousand MonteCarlo iterations of 

the risk assessment model using @Risk (Palisade Corporation, Newfield, New York ) and Excel 

(Microsoft Corporation, Redmond, Washington ). 

APHIS estimates that as a result of this trade, carried out with the appropriate systems mitigations and 

safeguards: 

• the most likely number of infested avocados reaching the United States each year is zero. 

• the most likely number of infested avocados reaching avocado growing counties in the United 

States each year is zero. 

• The most likely number of containers with at least one infested fruit is zero. 

APHIS also estimates with a 95% confidence that as a result of importing ‘Hass’ avocados from Mexico: 

• less than 350 infested avocados will reach the United States each year. 

• less than 66 infested avocados will reach avocado producing counties each year. 
 Page 71 

Summary of results:

The probability distributions for results are presented below: 

P1, Proportion of Avocados that are Infested

Probability Density Distribution

P1, the Distribution for the Proportion of Avocados Infested

0.00E+00 2.00E-07 4.00E-07 6.00E-07 8.00E-07 1.00E-06 1.20E-06 1.40E-06

 P1, the Proportion of Avocados Infested

Likelihood

95% confidence that P1<= 5.25E-07 
 Page 72 

Q1, Annual number of Infested avocados reaching the US

Probability Density Distribution

 Distribution for Q1 , Number Infested 

Avocados Entering USA Annually

0 250 500 750 1000

 Annual number of infested avocados reaching USA 

Likelihood

95% confidence that Q1 <= 364
 Page 73 

Q2, Annual number of Infested Avocados reaching counties with susceptible host material

Probability Density Distribution

 Distribution for Q2, Annual Number of Infested

 Avocados Reaching Avocado Producing Counties 

0 70 140 210 280 350

Q2: Annual number of infested avocados reaching avocado producing counties

Likelilhood

95% confidence that Q2 <= 70
 Page 74 

Appendix E – Approximation of the quantity of Hass avocados that would be imported 

from Mexico, if they were allowed to enter year-round into all States 

Phylo Evangelou 

This appendix is divided into three sections. The first presents an approximated range for the 

quantity of Hass avocados that would be imported into the United States from Mexico, if the 

Code of Federal Regulations were amended to allow year-round importation into all States. The 

second section sets forth some of the assumptions that underlie the approximation. The third 

section lists the steps followed in its derivation. 

The approach taken rests on the premise that quantities of Hass avocados imported from Mexico 

during the past six years, together with quantities imported from other countries and those 

supplied domestically during and prior to this period, provide a basis for approximating 

expanded imports from Mexico. Changes in the supply of Hass avocados in regions approved 

for imports from Mexico are applied to regions and times of the year for which imports from 

Mexico are currently prohibited. A range of import quantities is approximated, taking into 

consideration Mexico’s supply potential and differences among U.S. regional markets. 

Population projections are used to indicate how the approximated range may increase over time. 

The approximated range of Hass avocado imports from Mexico, if they were allowed to enter all 

States year-round, is 275 million pounds to 413 million pounds per year. Hass avocado imports 

from Mexico in 2002 totaled about 59 million pounds. Thus, they may be expected to increase 

to between four and seven times their current level. All things equal, the approximated range 

could become 295 million pounds to 442 million pounds per year after five years. 

Expanded Hass Avocado Imports from Mexico

Fresh Hass avocados from Mexico were allowed entry into the northeastern United States for the 

first time in November 1997.1

 Entry was allowed into 19 States and the District of Columbia 

during a four-month period, November through February. In 2001, the area approved for import 

was expanded by an additional 12 States, and the period of import was extended to six months, 

October 15 to April 15.2

 

The area previously approved to receive Hass avocados from Mexico corresponds to the 

Northeast and East Central regions designated in avocado shipment data compiled by the 

California Avocado Commission (CAC). States added to the approved area by the second rule 

correspond, with minor discrepancies, to CAC’s West Central region.3

 

1

 The effective date of the final rule was March 7, 1997. The approved area included Connecticut, Delaware, 

District of Columbia, Illinois, Indiana, Kentucky, Maine, Maryland, Massachusetts, Michigan, New Hampshire, 

New Jersey, New York, Ohio, Pennsylvania, Rhode Island, Vermont, Virginia, West Virginia, and Wisconsin. 

2

 The effective date of the final rule was November 1, 2001. The States added were Colorado, Idaho, Iowa, Kansas, 

Minnesota, Missouri, Montana, Nebraska, North Dakota, South Dakota, Utah, and Wyoming. 3

 The six regions are Northeast, East Central, West Central, Southeast, Southwest, and Pacific. The Pacific region 

includes shipment terminals in Idaho and Utah. Other than for these two States, all States approved by the 2001 

final rule to receive Hass avocados from Mexico correspond to terminal markets in CAC’s Northeast, East Central, 
 Page 75 

Entry of Hass avocados from Mexico into the Northeast and East Central regions, and more 

recently into the West Central region, has had dramatic supply effects. In the Northeast and East 

Central regions, the average supply of avocados during January, February, and December has 

increased by more than 140 percent, and in November, by more than 80 percent (Table 1). The 

simple average for the four months indicates an increase in total supply of 128 percent. At the 

same time, the quantity of Hass avocados supplied by California and foreign sources other than 

Mexico during the four months has fallen by an average of 57 percent (Table 2). 

Similar changes can be seen when the West Central region is included (Tables 3 and 4). 

However, the effects are not as clear-cut. We cannot distinguish among regional destinations for 

imports from Mexico; observed market changes due to allowing Hass avocado imports from 

Mexico into the West Central region are dampened by imports into the Northeast and East 

Central regions prior to November 2001. Also, for the months of March, April, and October, 

there is only one year of data that includes imports from Mexico, namely 2002. Nonetheless, the 

same pattern of increased total supply and reduced supply by California and foreign sources 

other than Mexico is apparent.1

Table 5, scenario 1, shows percentage increases in the total supply of Hass avocados and 

percentage decreases in the quantity supplied by California and foreign sources other than 

Mexico that are based on the changes observed in Tables 1-4. Seasonal differences (higher 

percentage changes from October to March, lower ones from May to August, with April and 

September as transition months) are included to account for the seasonal variability of avocado 

production in Mexico. 

Regional and total quantities of Hass avocados that would be imported from Mexico, assuming 

scenario 1 changes occurred in all regions are presented in Table 6, scenario 1. The results 

indicate that Hass avocado imports from Mexico would exceed 550 million pounds a year. This 

amount is greater than Mexico’s current production that can be certified for export to the United 

States. In addition, we do not believe that the entry of Hass avocado imports from Mexico into 

the Pacific, Southeast, and Southwest regions would have as strong an effect, percentage-wise, as 

has occurred in the Northeast, East Central, and West Central regions. The latter have always 

been relatively minor markets for California producers and importers from sources other than 

Mexico, whereas the Pacific region and California in particular is their single largest area of 

demand. Because of the above scenario was not considered realistic (specifically, 550 million 

pounds exceeds production capacity as noted above), that scenario was not included in this 

assessment. 

 and West Central regions. Since the quantities of Hass avocados shipped to Idaho and Utah are small, these 

discrepancies can be disregarded. 

1

 In Table 4, the anomalous increase in October 2002 may be partly attributable to that year’s surge in imports from 

sources other than Mexico (50% increase over 2001 imports) and October’s historically large share of these imports 

(30 percent). 
 Page 76 

Table 1. Hass avocados supplied to the Northeast and East Central regions, January, February, November, and 

December, 1994 to 2001, including imports from Mexico, pounds 

 

 January February November December 

1994 2,590,680 2,284,462 2,889,853 2,329,671 

1995 2,930,085 2,463,722 4,702,680 2,883,405 

1996 3,494,143 3,603,430 5,547,622 3,413,139 

1997 4,239,303 3,926,758 6,031,334 5,978,564 

1998 7,176,472 6,041,963 6,381,416 6,007,244 

1999 6,936,146 6,729,956 8,724,254 6,688,487 

2000 7,615,616 7,472,906 8,188,139 8,269,977 

2001 9,913,767 9,943,446 11,106,149 8,061,474 

 

Monthly average prior to imports 

from Mexico1

 3,313,553 3,069,593 4,380,052 2,875,405 

 

Monthly average for months that 

include imports from Mexico2

 7,910,500 7,547,068 8,086,258 7,001,149 

 

Percent change from the first to the 

second average 138.7% 145.9% 84.6% 143.5% 

Sources: California Avocado Commission for shipments from California, and the U.S. Census Bureau for imports. 

Note: The regional distribution of imports other than from Mexico is assumed to be the same as the distribution for 

California shipments. The monthly distribution of imports other than from Mexico is based on their 1985-1995 average 

distribution. The monthly distribution of imports from Mexico, November 1997 through December 2001, is assumed to 

be 25 percent each for January, February, November, and December. Data on imports has been adjusted to exclude 

non-Hass varieties. California shipments for which the regional destination was not identified are not included; they 

comprised, on average, only 0.4 percent of California shipments from 1994/95 to 2001/02. 

1

 January, 1994-1997; February, 1994-1997; November, 1994-1996; December, 1994-1996. 

2

 January, 1998-2001; February, 1998-2001; November, 1997-2001; December, 1997-2001. 
 Page 77 

Table 2. Hass avocados supplied to the Northeast and East Central regions, January, February, November, and 

December, 1994 to 2001, not including imports from Mexico, pounds 

 

 January February November December 

1994 2,590,680 2,284,462 2,889,853 2,329,671 

1995 2,930,085 2,463,722 4,702,680 2,883,405 

1996 3,494,143 3,603,430 5,547,622 3,413,139 

1997 4,239,303 3,926,758 1,590,326 1,537,556 

1998 2,155,471 1,020,962 1,360,415 986,243 

1999 565,800 359,610 2,353,908 318,141 

2000 519,655 376,945 1,092,178 1,174,016 

2001 2,999,281 3,028,960 4,191,663 1,146,988 

 

Monthly average prior to imports 

from Mexico1

 3,313,553 3,069,593 4,380,052 2,875,405 

 

Monthly average for months when 

imports from Mexico were allowed2

 1,560,052 1,196,619 2,117,698 1,032,589 

 

Percent change from the first to the 

second average -52.9% -61.0% -51.7% -64.1% 

Sources: California Avocado Commission for shipments from California, and the U.S. Census Bureau for imports. 

Note: The regional distribution of imports is assumed to be the same as the distribution for California shipments. 

The monthly distribution of imports is based on their 1985-1995 average distribution. Data on imports has been 

adjusted to exclude non-Hass varieties. California shipments for which the regional destination was not identified 

are not included; they comprised, on average, only 0.4 percent of California shipments from 1994/95 to 2001/02. 

1

 January, 1994-1997; February, 1994-1997; November, 1994-1996; December, 1994-1996. 

2

 January, 1998-2001; February, 1998-2001; November, 1997-2001; December, 1997-2001. 
 Page 78 

Table 3. Hass avocados supplied to the Northeast, East Central, and West Central regions, January-April and 

October-December, 1994 to 2002, including imports from Mexico, pounds 

 

 January February March April October November December

1994 3,701,598 3,030,810 4,197,798 4,719,436 4,204,455 3,534,724 3,432,717

1995 3,826,140 3,377,574 4,600,470 5,185,707 6,019,307 3,945,415 3,917,373

1996 4,800,544 4,885,705 5,584,586 6,963,758 6,105,430 5,358,173 4,529,584

1997 5,493,122 5,214,515 5,701,271 6,427,522 4,975,958 6,979,322 7,360,413

1998 8,894,686 7,433,600 5,255,560 7,670,960 8,915,562 7,842,602 7,978,211

1999 8,185,395 7,963,462 4,751,107 6,890,983 7,851,918 10,100,348 7,692,027

2000 9,306,298 8,905,448 6,434,911 7,739,903 10,162,448 10,634,987 9,730,278

2001 12,079,836 11,849,398 6,726,203 10,990,368 13,915,082 13,255,814 9,047,991

2002 13,694,206 14,042,418 12,206,594 8,174,666 19,183,379 12,571,385 12,896,700

 

Monthly average prior to 

imports from Mexico1

 4,455,351 4,127,151 5,406,488 7,073,580 7,768,770 4,279,437 3,959,891

 

Monthly average for months 

that include imports from 

Mexico2

 10,432,084 10,038,865 12,206,594 8,174,666 19,183,379 10,230,743 9,117,603

 

Percent change from the first 

To the second average 134.1% 143.2% 125.8% 15.6% 146.9% 139.1% 130.2%

Sources: California Avocado Commission for shipments from California, and the U.S. Census Bureau for imports. 

Note: The regional distribution of imports other than from Mexico is assumed to be the same as the distribution for 

California shipments. The monthly distribution of imports other than from Mexico is based on their 1985-1995 average 

distribution. The monthly distribution of imports from Mexico, November 1997 through December 2001, is assumed to 

be 25 percent each for January, February, November, and December. The monthly distribution of imports from Mexico 

for 2002 is assumed to be as follows: January, February, and December, 18 percent; March and November, 16 percent; 

and April and October, 7 percent. Data on imports has been adjusted to exclude non-Hass varieties. California 

shipments for which the regional destination was not identified are not included; they comprised, on average, only 0.4 

percent of California shipments from 1994/95 to 2001/02. 

1

 January, 1994-1997; February, 1994-1997; March, 1994-2001; April, 1994-2001; October, 1994-2001; November, 

1994-1996; December, 1994-1996. 

2

 January, 1998-2002; February, 1998-2002; March, 2002; April, 2002; October, 2002; November, 1997-2002; 

December, 1997-2002.
 Page 79 

Table 4. Hass avocados supplied to the Northeast, East Central, and West Central regions, January-April and 

October-December, 1994 to 2002, not including imports from Mexico, pounds 

 

 January February March April October November December

1994 3,701,598 3,030,810 4,197,798 4,719,436 4,204,455 3,534,724 3,432,717

1995 3,826,140 3,377,574 4,600,470 5,185,707 6,019,307 3,945,415 3,917,373

1996 4,800,544 4,885,705 5,584,586 6,963,758 6,105,430 5,358,173 4,529,584

1997 5,493,122 5,214,515 5,701,271 6,427,522 4,975,958 2,538,314 2,919,405

1998 3,873,685 2,412,599 5,255,560 7,670,960 8,915,562 2,821,601 2,957,210

1999 1,815,049 1,593,116 4,751,107 6,890,983 7,851,918 3,730,002 1,321,681

2000 2,210,337 1,809,487 6,434,911 7,739,903 10,162,448 3,539,026 2,634,317

2001 5,165,350 4,934,912 6,726,203 10,990,368 13,915,082 6,341,328 2,133,505

2002 3,111,492 3,459,704 2,799,737 4,059,166 15,067,879 3,164,528 2,313,986

 

Monthly average prior to 

imports from Mexico1

 4,455,351 4,127,151 5,406,488 7,073,580 7,768,770 4,279,437 3,959,891

 

Monthly average for months 

when imports from 

Mexico were allowed2

 3,235,183 2,841,964 2,799,737 4,059,166 15,067,879 3,689,133 2,380,017

 

Percent change from the first 

To the second average -27.4% -31.1% -48.2% -42.6% 94.0% -13.8% -39.9%

Sources: California Avocado Commission for shipments from California, and the U.S. Census Bureau for imports. 

Note: The regional distribution of imports is assumed to be the same as the distribution for California shipments. 

The monthly distribution of imports is based on their 1985-1995 average distribution. Data on imports has been 

adjusted to exclude non-Hass varieties. California shipments for which the regional destination was not identified 

are not included; they comprised, on average, only 0.4 percent of California shipments from 1994/95 to 2001/02. 

1

 January, 1994-1997; February, 1994-1997; March, 1994-2001; April, 1994-2001; October, 1994-2001; November, 

1994-1996; December, 1994-1996. 

2

 January, 1998-2002; February, 1998-2002; March, 2002; April, 2002; October, 2002; November, 1997-2002; 

December, 1997-2002. 
 Page 80 

Table 5. Percentage changes in the total supply of Hass avocados and in the quantities supplied by California and 

foreign sources other than Mexico, if imports from Mexico were allowed to enter year-round into all States, for four scenarios 

 

 Increase in Decrease in the Supply by California

 Total Supply and Foreign Sources other than Mexico

 

Scenario 1 

 January, February, 

 March, October, 

 November, December 120% 60%

 

 April and September 80% 40%

 May, June, July, August 40% 20%

Scenario 2 

 January, February, 

 March, October, 

 November, December 90% 45%

 

 April and September 60% 30%

 May, June, July, August 30% 15%

Scenario 3 

 January, February, 

 March, October, 

 November, December 75% 37.5%

 

 April and September 50% 25%

 May, June, July, August 25% 12.5%

Scenario 4 

 January, February, 

 March, October, 

 November, December 60% 30%

 

 April and September 40% 20%

 May, June, July, August 20% 10%

Note: Assumed seasonal differences reflect the seasonality of production of Hass avocados in Mexico. 
 Page 81 

 

Table 6. Four approximations of the supply of Hass avocados by Mexico, and by California 

and foreign sources other than Mexico, if imports from Mexico were allowed to enter year-round 

into all States, pounds 

 CA Shipments

 Imports from and Imports other

 Mexico than from Mexico Total Supply

 

Scenario 1 

 Pacific 273,980,202 130,665,100 404,645,302

 Southeast 57,140,036 23,152,393 80,292,430

 Southwest 117,516,222 53,041,117 170,557,338

 Northeast 34,948,304 22,133,188 57,081,492

 East Central 38,106,275 22,123,533 60,229,808

 West Central 28,522,107 13,905,616 42,427,723

 Total 550,213,146 265,020,947 815,234,093

 

Scenario 2 

 Pacific 205,485,151 153,496,783 358,981,935

 Southeast 42,855,027 27,914,063 70,769,090

 Southwest 88,137,166 62,834,135 150,971,301

 Northeast 26,211,228 25,045,547 51,256,775

 East Central 28,579,706 25,299,056 53,878,762

 West Central 21,391,580 16,282,458 37,674,039

 Total 412,659,860 310,872,042 723,531,902

 

Scenario 3 

 Pacific 171,237,626 164,912,625 336,150,251

 Southeast 35,712,523 30,294,898 66,007,420

 Southwest 73,447,639 67,730,644 141,178,283

 Northeast 21,842,690 26,501,726 48,344,416

 East Central 23,816,422 26,886,817 50,703,239

 West Central 17,826,317 17,470,879 35,297,196

 Total 343,883,216 333,797,590 677,680,807

 

Scenario 4 

 Pacific 136,990,101 176,328,467 313,318,568

 Southeast 28,570,018 32,675,733 61,245,751

 Southwest 58,758,111 72,627,154 131,385,264

 Northeast 17,474,152 27,957,906 45,432,058

 East Central 19,053,138 28,474,579 47,527,716

 West Central 14,261,054 18,659,300 32,920,354

 Total 275,106,573 356,723,138 631,829,711

Note: Approximations begin with regional yearly supply averages for the four-year period, 

1999-2002, not including imports from Mexico. Assumed increases in the total supply of avocados, 

and decreases in the quantities supplied by California and foreign sources other than Mexico, are 

shown in Table 5. 

Taking these factors into consideration, three other scenarios with lower percentage changes are 
 Page 82 

set forth (Table 5, scenarios 2-4), and the corresponding quantities calculated 

(Table 6, scenarios 2-4). Imports from Mexico for scenarios 2 and 4 are used as end-points for 

the approximated range: 275 million pounds to 413 million pounds per year. It is noted that 

approximated imports from Mexico for the Northeast, East Central, and West Central regions in 

scenario 3, 63 million pounds, is similar to the 59 million pounds of Hass avocados imported 

from Mexico by those regions during the allowed months of 2002. 

An appreciation for how this range in imports from Mexico may increase over time can be 

gained by applying regional rates of population growth. As shown in Table 7, the 

approximated range would become 295 million pounds to 442 million pounds per year in 

five years, assuming Mexico’s percentage share of the regional markets remained the same 

and without considering regional differences in per capita avocado consumption. 

Table 7. Projected increase after five years in the approximated range of Hass avocado imports from Mexico, 

based on regional population growth rates, pounds 

 

 Annual 

 Approximated Range Growth Projected Range of Imports 

 Region of Imports from Mexico1

 Rate2 from Mexico after Five Years 

 

 Pacific 136,990,101 to 205,485,151 1.7% 149,036,949 to 23,555,423 

 Southeast 28,570,018 to 42,855,027 1.1% 30,176,321 to 45,264,482 

 Southwest 58,758,111 to 88,137,166 1.7% 63,925,273 to 95,887,909 

 Northeast 17,474,152 to 26,211,228 0.4% 17,826,442 to 26,739,663 

 East Central 19,053,138 to 28,579,706 0.4% 19,437,261 to 29,155,892 

 West Central 14,261,054 to 21,391,580 0.4% 14,548,566 to 21,822,848 

 

 Total 275,106,573 to 412,659,860 294,950,811 to 442,426,217 

Note: The projections assume that the relative shares of Hass avocados supplied by Mexico, other foreign sources, 

and California remain unchanged. Regional differences in per capita avocado consumption are not considered. 

1

Imports from Mexico, Table 6, scenarios 2 and 4. 

2

Campbell 1996. The population growth rate for the West, 1.7%, is used for the Pacific and Southwest regions. 

Assumptions

1. Data on U.S. avocado supplies used in making the approximation can be appropriately 

restricted to the Hass variety. 

Hass is the only variety allowed to be imported from Mexico as whole fresh fruit. Any 

regulatory change allowing expanded imports would also only concern Hass avocados. It is the 

principal variety grown in the United States, comprising 90 percent of California shipments, 

1991/92 to 2001/02.1

 Avocado imports from countries other than Mexico are mainly Hass 

variety. 

Hass avocados have a market distinct from green avocado varieties. Substantial and prevailing 

 

1

 Hass avocados are not produced in Florida and the quantity that may be produced in Hawaii is negligible. 
 Page 83 

price differences underscore the Hass’s low substitutability with other varieties. The fact that the 

avocado promotion, research, and information order issued last year by USDA’s Agricultural 

Marketing Service is only for Hass avocados is an indication of domestic and foreign producers’ 

interest in promoting the variety’s distinctiveness (Federal Register, Vol. 67, No. 173, 

September 6, 2002). 

2. The quantity of Hass avocados that could be potentially supplied by Mexico is considerably 

larger than is now being imported. 

Only about two of every nine tons of Hass avocados produced per hectare in certified orchards in 

Mexico are exported to the United States.1

 The rest of the crop is exported to Europe or 

elsewhere, or consumed within Mexico. Thus, less than one-fourth of the certified fruit is being 

shipped to the United States, while the area certified for export to the United States continues to 

expand (12,149 hectares in 2001/02, 16,430 hectares in 2002/03, and a projected 23,000 hectares 

in 2003/04). In round figures, about 450 million pounds of Hass avocados could be available for 

export to the United States in 2003/04.2

 

3. Quantities of Hass avocados imported from Mexico are determined by importers’ desire to 

maintain market prices, the flexibility afforded by lower production costs in Mexico compared to 

those in the United States, and projections for overall market growth. 

The quantity of avocados offered for sale in the United States has a strong, negative impact on 

price (Carman and Craft 1998). The fact that Hass avocado imports from Mexico are but a 

fraction of the quantity that are certified for export to the United States and could be supplied 

underscores importers’ appreciation of the fruit’s inelastic demand, estimated by Carman and 

Green (1993) to be -0.86. This means that declines in price due to increased supply result in 

lower total revenue; the percentage drop in price is greater than the percentage increase in 

demand, or quantity of avocados sold. 

On the other hand, lower costs of production in Mexico give that country’s exporters an added 

cushion against price declines, and greater flexibility in responding to market changes. As has 

occurred in the Northeast, East Central, and West Central regions, imports from Mexico would 

be expected to claim sizable shares of expanding markets in the Pacific, Southeast, and 

Southwest regions. Producers in Mexico are better able to weather price declines than their U.S. 

counterparts. 

4. Seasonality of Hass avocado production in Mexico may cause seasonal variation in exports to 

the United States, but the variation should be moderate. 

 

Avocado growers can store the fruit on the tree for up to three or four months once it is ready to 

be harvested, to allow for market fluctuations; the fruit continues to grow. The timing of harvest 

therefore depends more on marketing opportunities than on the fruit’s ripeness. Hass avocados 

have a longer season than other varieties, and in addition, those grown in Mexico have an extra 

bloom per season (flor loco, or crazy bloom). Five blooms per year compared to the four blooms 

 

1

 Ron Campbell, SPS Consultants, personal communication. 

2

 (23,000 hectares)(9,000 kilograms/hectare/year)(2.205 pounds/kilogram) = 456,435,000 pounds/year. 
 Page 84 

that are normal elsewhere is another reason why Mexico can produce avocados year-round with 

moderate seasonal variability.1

 

Although harvested year-round, Hass avocados grown in Mexico reach their peak productivity 

between October and February, with a broader period of above-average production from 

September through March.2

 In contrast, the main season for California shipments of Hass 

avocados is March to September. 

5. The regional distribution of Hass avocado imports other than from Mexico is largely the same 

as the distribution of domestically produced Hass avocados. 

This assumption is supported by industry opinion. California, for example, is the largest single 

market for both domestically produced Hass avocados and Hass avocados from Chile, our main 

foreign supplier. 

Steps Followed

1. Using data supplied by the California Avocado Commission, a database was created of 

monthly Hass avocado shipments by regional destination (domestic shipments), beginning with 

the 1991/1992 season. (The crop year for avocados runs from November through October.) 

2. Avocado import data reported by the Census Bureau and provided by the World Trade Atlas 

were adjusted to eliminate non-Hass imports. Hass avocado imports began to be reported 

separately in July 2001.3

 Each country’s proportion of Hass avocado exports to the United States 

from mid-2001 to the end of 2002 was applied to previous years’ exports, beginning in 1994.4

 

3. Hass avocado yearly import totals for foreign sources other than Mexico were distributed 

monthly, based on the average monthly distribution of imports reported for 1985-1995 (Carman 

and Craft 1998, Appendix Table 8).5

 

4. The Hass avocado import totals for foreign sources other than Mexico, by year and month, 

were added to domestic shipments and distributed among the regions in proportion to the 

domestic shipments. 

5. Yearly Hass avocado imports from Mexico were distributed monthly as follows. For 

November 1997 through December 2001, 25 percent each was apportioned to November, 

 

1

 Ron Campbell, SPS Consultants, personal communication. 

2 www.marketag.com/ma/bulletins/market/avocado.stm, and Ron Campbell, SPS Consultants, personal 

communication. 

3

 Harmonized Schedule 0804.40.0010, Hass avocados and avocados determined by the Secretary of USDA to be 

Hass-like. 

4

 Principal foreign sources of avocados and approximated shares of imports from these sources that were of the Hass 

variety, 1994-2002, are as follows: Chile, 99.7%; Mexico, 97.7%; New Zealand, 97.4%; Dominican Republic, 

20.6%, Bahamas, none; Other, 98.8%. The percentage of avocados imported by the United States annually that 

were of the Hass variety averaged 84.2%, 1994-2002, and 89.6%, 1998-2002. 

5

 Monthly distribution of imports: January, 6.4%; February, 1.6%; March, 0.3%; April, 0.4%; May, 0.5%; June, 

1.3%; July, 2.3%; August, 3.2%; September, 15.4%; October, 29.9%; November, 27.4%; and December, 11.3%. 
 Page 85 

December, January, and February. For January though December 2002, 18 percent each was 

apportioned to January, February, and December; 16 percent each was apportioned to March and 

November; and 7 percent each was apportioned to April and October.1

At the time this assessment was done, we did not have access to information on monthly 

quantities of Hass avocados imported from Mexico. A recalculation using actual monthly import 

levels would not alter the approximations significantly. 

6. Hass avocado imports from Mexico were added to the sum of domestic shipments and 

imports other than from Mexico, by month. Quantities for the Northeast and East Central 

regions were combined for November 1997 through December 2001. The West Central region 

was included for 2002. 

7. Monthly percentage increases in the Hass avocado supply with Mexico’s entry into the 

market were calculated for the Northeast and East Central regions, 1994 to 2001, and including 

the West Central region in 2002 (Tables 1 and 3). Percentage decreases in quantities of Hass 

avocados supplied by California and foreign sources other than Mexico were calculated for the 

same regions for the same periods (Tables 2 and 4). 

8. The observed percentage changes in the Northeast, East Central, and West Central regions 

were generalized (Table 5, scenario 1). Expected seasonal variation in the supply of Hass 

avocados from Mexico was acknowledged by assuming smaller percentage changes when 

Mexico’s production is lower. The generalized changes were applied to the four-year average, 

1999-2002, of Hass avocado quantities supplied by California and foreign sources other than 

Mexico to all regions for all months (Table 6, scenario 1). 

9. The generalized percentage changes were adjusted downward, in recognition of Mexico’s 

supply capacity and the strong market positions held in the Pacific and Southwest regions by 

California and foreign suppliers other than Mexico (Table 5, scenarios 2-4). Application of these 

adjusted percentage changes yielded the approximated range of expanded Hass avocado imports 

from Mexico, as shown in scenarios 2 and 4 of Table 6. 

 

10. Census Bureau regional population projections were applied to the approximated range to 

show how it may increase in the near future.2

REFERENCES 

 

1

 The percentage distributions for November and December, 2001, were kept at 25% of the 2001 yearly total for 

ease of calculation. These two months’ share of the yearly total may well have been higher, since the market had 

just broadened to include the West Central region. 

2

 Annual rates of population increase projected for regions of the United States, 1995 to 2025, are Northeast, 0.4%; 

Midwest, 0.4%; South, 1.1%; and West, 1.7% (Campbell 1996). It is noted that U.S. annual per capita consumption 

of avocados increased from less than one-half pound in the early 1960s, to over two pounds in 1987 (Carman and 

Green 1993). Data indicate that there has not been an appreciable increase in U.S. per capita consumption since the 

mid-1980s. However, above-average per capita avocado consumption in the Pacific and Southwest would suggest 

even more rapid market growth could be expected in those fast-growing regions than is indicated by population 

projections alone. 
 Page 86 

Campbell, Paul R. 1996. “Population Projections for States by Age, Sex, Race, and Hispanic 

Origin: 1995 to 2025.” U.S. Bureau of the Census, Population Division, 

www.census.gov/population/www/projections/ppl47.html. 

Carman, Hoy F., and R. Kim Craft. 1998. “An Economic Evaluation of California Avocado 

Industry Marketing Programs, 1961-1995.” Giannini Foundation Research Report Number 345, 

University of California. 

Carman, Hoy F., and Richard D. Green. 1993. “Commodity Supply Response to a ProducerFinanced Advertising Program: The California Avocado Industry.” Agribusiness, Vol. 9, No. 6, 

605-621. 
Appendix F 

 Page 87 

Appendix F – 7CFR§319.56-2ff 

Administrative instructions governing movement of Hass avocados from Michoacán, 

Mexico, to approved States. 

Fresh Hass variety avocados (Persea americana) may be imported from Michoacan, Mexico, into the United States for 

distribution in approved States only under a permit issued in accordance with § 319.56-4, and only under the following 

conditions: 

(a) Shipping restrictions. 

(1) The avocados may be imported in commercial shipments only; 

(2) The avocados may be imported only between October 15 and April 15 of the following year; and 

(3) The avocados may be distributed only in the following States: Colorado, Connecticut, Delaware, the District of 

Columbia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Maine, Maryland, Massachusetts, Michigan, 

Minnesota, Missouri, Montana, Nebraska, New Hampshire, New Jersey, New York, North Dakota, Ohio, 

Pennsylvania, Rhode Island, South Dakota, Utah, Vermont, Virginia, West Virginia, Wisconsin, and Wyoming. 

(b) Trust fund agreement. The avocados may be imported only if the Mexican avocado industry association representing 

Mexican avocado growers, packers, and exporters has entered into a trust fund agreement with the Animal and Plant 

Health Inspection Service (APHIS) for that shipping season. That agreement requires the Mexican avocado industry 

association to pay in advance all estimated costs that APHIS expects to incur through its involvement in the 

trapping, survey, harvest, and packinghouse operations prescribed in paragraph (c) of this section. These costs will 

include administrative expenses incurred in conducting the services and all salaries (including overtime and the 

Federal share of employee benefits), travel expenses (including per diem expenses), and other incidental expenses 

incurred by the inspectors in performing these services. The agreement requires the Mexican avocado industry 

association to deposit a certified or cashier's check with APHIS for the amount of those costs, as estimated by 

APHIS. If the deposit is not sufficient to meet all costs incurred by APHIS, the agreement further requires the 

Mexican avocado industry association to deposit with APHIS a certified or cashier's check for the amount of the 

remaining costs, as determined by APHIS, before the services will be completed. After a final audit at the 

conclusion of each shipping season, any overpayment of funds would be returned to the Mexican avocado industry 

association or held on account until needed. 

(c) Safeguards in Mexico. The avocados must have been grown in the Mexican State of Michoacan in an orchard located 

in a municipality that meets the requirements of paragraph (c)(1) of this section. The orchard in which the avocados 

are grown must meet the requirements of paragraph (c)(2) of this section. The avocados must be packed for export 

to the United States in a packinghouse that meets the requirements of paragraph (c)(3) of this section. Sanidad 

Vegetal must provide an annual work plan to APHIS that details the activities that Sanidad Vegetal will, subject to 

APHIS' approval of the work plan, carry out to meet the requirements of this section; APHIS will be directly 

involved with Sanidad Vegetal in the monitoring and supervision of those activities. The personnel conducting the 

trapping and pest surveys must be hired, trained, and supervised by Sanidad Vegetal or by the Michoacan State 

delegate of the Secretaria de Agricultura, Ganaderia y Desarrollo Rural (SAGDR). 

(1) Municipality requirements. 

(i) The municipality must be listed as an approved municipality in the annual work plan provided to APHIS by 

Sanidad Vegetal. 

(ii) The municipality must be surveyed at least annually and found to be free from the large avocado seed 

weevil Heilipus lauri, the avocado seed moth Stenoma catenifer, and the small avocado seed weevils 

Conotrachelus aguacatae and C. perseae. The survey must cover at least 300 hectares in the municipality 

and include randomly selected portions of each registered orchard and areas with wild or backyard avocado 

trees. The survey must be conducted during the growing season and completed prior to the harvest of the 

avocados. 

(iii) Trapping must be conducted in the municipality for Mediterranean fruit fly (Medfly) (Ceratitis capitata) at 

the rate of 1 trap per 1 to 4 square miles. Any findings of Medfly must be reported to APHIS. 

(2) Orchard and grower requirements. The orchard and the grower must be registered with Sanidad Vegetal's 

avocado export program and must be listed as an approved orchard or an approved grower in the annual work plan 
Appendix F 

 Page 88 

provided to APHIS by Sanidad Vegetal. The operations of the orchard must meet the following conditions: 

(i) The orchard and all contiguous orchards and properties must be surveyed annually and found to be free from 

the avocado stem weevil Copturus aguacatae. The survey must be conducted during the growing season 

and completed prior to the harvest of the avocados. 

(ii) Trapping must be conducted in the orchard for the fruit flies Anastrepha ludens, A. serpentina, and A. 

striata at the rate of one trap per 10 hectares. If one of those fruit flies is trapped, at least 10 additional traps 

must be deployed in a 50-hectare area immediately surrounding the trap in which the fruit fly was found. If 

within 30 days of the first finding any additional fruit flies are trapped within the 260-hectare area 

surrounding the first finding, malathion bait treatments must be applied in the affected orchard in order for 

the orchard to remain eligible to export avocados. 

(iii) Avocado fruit that has fallen from the trees must be removed from the orchard at least once every 7 days 

and may not be included in field boxes of fruit to be packed for export. 

(iv) Dead branches on avocado trees in the orchard must be pruned and removed from the orchard. 

(v) Harvested avocados must be placed in field boxes or containers of field boxes that are marked to show the 

Sanidad Vegetal registration number of the orchard. The avocados must be moved from the orchard to the 

packinghouse within 3 hours of harvest or they must be protected from fruit fly infestation until moved. 

(vi) The avocados must be protected from fruit fly infestation during their movement from the orchard to the 

packinghouse and must be accompanied by a field record indicating that the avocados originated from a 

certified orchard. 

(3) Packinghouse requirements. The packinghouse must be registered with Sanidad Vegetal's avocado export 

program and must be listed as an approved packinghouse in the annual work plan provided to APHIS by Sanidad 

Vegetal. The operations of the packinghouse must meet the following conditions: 

(i) During the time the packinghouse is used to prepare avocados for export to the United States, the 

packinghouse may accept fruit only from orchards certified by Sanidad Vegetal for participation in the 

avocado export program. 

(ii) All openings to the outside must be covered by screening with openings of not more than 1.6 mm or by 

some other barrier that prevents insects from entering the packinghouse. 

(iii) The packinghouse must have double doors at the entrance to the facility and at the interior entrance to the 

area where the avocados are packed. 

(iv) Prior to the culling process, a sample of 300 avocados per shipment must be selected, cut, and inspected by 

Sanidad Vegetal and found free from pests. 

(v) The identity of the avocados must be maintained from field boxes or containers to the shipping boxes so the 

avocados can be traced back to the orchard in which they were grown if pests are found at the 

packinghouse or the port of first arrival in the United States. 

(vi) Prior to being packed in boxes, each avocado fruit must be cleaned of all stems, leaves, and other portions 

of plants and labeled with a sticker that bears the Sanidad Vegetal registration number of the packinghouse. 

(vii) The avocados must be packed in clean, new boxes, or clean plastic reusable crates. The boxes or crates 

must be clearly marked with the identity of the grower, packinghouse, and exporter, and the statement "Not 

for distribution in AL, AK, AZ, AR, CA, FL, GA, HI, LA, MS, NV, NM, NC, OK, OR, SC, TN, TX, WA, 

Puerto Rico, and all other U.S. Territories." 

(viii) The boxes must be placed in a refrigerated truck or refrigerated container and remain in that truck or 

container while in transit through Mexico to the port of first arrival in the United States. Prior to leaving 

the packinghouse, the truck or container must be secured by Sanidad Vegetal with a seal that will be 

broken when the truck or container is opened. Once sealed, the refrigerated truck or refrigerated container 

must remain unopened until it reaches the port of first arrival in the United States. 

(ix) Any avocados that have not been packed or loaded into a refrigerated truck or refrigerated container by the 

end of the work day must be kept in the screened packing area. 

(d) Certification. All shipments of avocados must be accompanied by a phytosanitary certificate issued by Sanidad 

Vegetal certifying that the conditions specified in this section have been met. 

(e) Pest detection. 
Appendix F 

 Page 89 

(1) If any of the avocado seed pests Heilipus lauri, Conotrachelus aquacatae, C. perseae, or Stenoma catenifer are 

discovered in a municipality during an annual pest survey, orchard survey, packinghouse inspection, or other 

monitoring or inspection activity in the municipality, Sanidad Vegetal must immediately initiate an 

investigation and take measures to isolate and eradicate the pests. Sanidad Vegetal must also provide APHIS 

with information regarding the circumstances of the infestation and the pest risk mitigation measures taken. The 

municipality in which the pests are discovered will lose its pest-free certification and avocado exports from that 

municipality will be suspended until APHIS and Sanidad Vegetal agree that the pest eradication measures taken 

have been effective and that the pest risk within that municipality has been eliminated. 

(2) If Sanidad Vegetal discovers the stem weevil Copturus aguacatae in an orchard during an orchard survey or 

other monitoring or inspection activity in the orchard, Sanidad Vegetal must provide APHIS with information 

regarding the circumstances of the infestation and the pest risk mitigation measures taken. The orchard in which 

the pest was found will lose its export certification immediately and will be denied export certification for the 

entire shipping season of October 15 through April 15. 

(3) If Sanidad Vegetal discovers the stem weevil Copturus aguacatae in fruit at a packinghouse, Sanidad Vegetal 

must investigate the origin of the infested fruit and provide APHIS with information regarding the 

circumstances of the infestation and the pest risk mitigation measures taken. The orchard where the infested 

fruit originated will lose its export certification immediately and will be denied export certification for the 

entire shipping season of October 15 through April 15. 

(f) Ports. The avocados may enter the United States at: 

(1) Any port located in a State specified in paragraph (a)(3) of this section; 

(2) The ports of Galveston or Houston, TX, or the border ports of Nogales, AZ, or Brownsville, Eagle Pass, El Paso, 

Hidalgo, or Laredo, TX; or 

(3) Other ports within that area of the United States specified in paragraph (g) of this section. 

(g) Shipping areas. 

(1) Except as explained below in paragraph (g)(3) for avocados that enter the United States at Nogales, AZ, 

avocados moved by truck or rail car may transit only that area of the United States bounded as follows: 

(i) On the east and south by a line extending from Brownsville, TX, to Galveston, TX, to Kinder, LA, to 

Memphis, TN, to Knoxville, TN, following Interstate 40 to Raleigh, NC, and due east from Raleigh, and 

(ii) On the west by following Interstate 10 North from El Paso, TX, to Las Cruces, NM, and north following 

Interstate 25 to the Colorado border, then west along Colorado and Utah's southern borders, then north 

along Utah's western border, then west along Idaho's southern border and north along Idaho's western 

border to the border with Canada. 

(2) All cities on the boundary lines described in paragraph (g)(1) are included in this shipping area. If the avocados 

are moved by air, the aircraft may not land outside this shipping area. 

(3) Avocados that enter the United States at Nogales, AZ, must be moved to Las Cruces, NM, by the route specified 

on the permit, and then must remain within the shipping area described above in this paragraph. 

(h) Shipping requirements. The avocados must be moved through the United States either by air or in a refrigerated truck 

or refrigerated rail car or in a refrigerated container on a truck or rail car. If the avocados are moved in a refrigerated 

container on a truck or rail car, an inspector must seal the container with a serially numbered seal at the port of first 

arrival in the United States. If the avocados are moved in a refrigerated truck or a refrigerated rail car, an inspector 

must seal the truck or rail car with a serially numbered seal at the port of first arrival in the United States. If the 

avocados are transferred to another vehicle or container in the United States, an inspector must be present to 

supervise the transfer and must apply a new serially numbered seal. The avocados must be moved through the 

United States under Customs bond. 

(i) Inspection. The avocados are subject to inspection by an inspector at the port of first arrival, at any stops in the United

States en route to an approved State, and upon arrival at the terminal market in the approved States. At the port of 

first arrival, an inspector will sample and cut avocados from each shipment to detect pest infestation. 
Appendix F 

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(j) Repackaging. If any avocados are removed from their original shipping boxes and repackaged, the stickers required 

by paragraph (c)(3)(vi) of this section may not be removed or obscured and the new boxes must be clearly marked 

with all the information required by paragraph (c)(3)(vii) of this section. 

(k) Compliance agreements. 

(1) Any person, other than the permittee, who moves or distributes the avocados following their importation into the 

United States (i.e., a second-party or subsequent handler) must enter into a compliance agreement with APHIS. 

In the compliance agreement, the person must acknowledge, and agree to observe, the requirements of 

paragraph (a) and paragraphs (f) through (k) of this section. Compliance agreement forms are available, free of 

charge, from local offices of Plant Protection and Quarantine, which are listed in local telephone directories. 

A compliance agreement will not be required for an individual place of business that only offers the avocados 

for sale directly to consumers. 

(2) Before transferring the avocados to any person (i.e., a second-party handler) for movement or distribution, the 

permittee must confirm that the second-party handler has entered into a compliance agreement with APHIS as 

required by paragraph (k)(1) of this section. If the permittee transfers the avocados to a second-party handler 

who has not entered into a compliance agreement, APHIS may revoke the permittee's import permit for the 

remainder of the current shipping season. 

(3) Any second-party or subsequent handler who transfers the avocados to another person for movement or 

distribution must confirm that the person receiving the avocados has entered into a compliance agreement with 

APHIS as required by paragraph (k)(1) of this section. If the second-party or subsequent handler transfers the 

avocados to a person who has not entered into a compliance agreement, APHIS may revoke the handler's 

compliance agreement for the remainder of the current shipping season. 

(4) Action on repeat violators. APHIS may deny an application for an import permit from, or refuse to enter into a 

compliance agreement with, any person who has had his or her import permit or compliance agreement revoked 

under paragraph (k)(2) or (k)(3) of this section twice within any 5-year period. 

(Approved by the Office of Management and Budget under control number 0579-0129) 

[62 FR 5313, Feb. 5, 1997, as amended at 64 FR 68005, Dec. 6, 1999; 66 FR 55551, Nov. 1, 2001]