United States Department of Agriculture

Animal and Plant Health Inspection Service

Plant Protection and Quarantine

Interstate Movement of Mature Green ‘Sharwil’ Avocado, 

Persea americana Mill. from Hawaii into the Continental 

United States

Risk Management Document

June 22, 2012

Plant Health Programs (PHP)

Regulations, Permits and Manuals (RPM)

Contact Person: David Lamb
3

Introduction

The United States Department of Agriculture’s Animal and Plant Health Inspection Service 

(USDA-APHIS) has received a request from the Hawaii Department of Agriculture (HDOA) to 

allow interstate movement of mature green ‘Sharwil’ avocado fruit into the continental United 

States. Since importation of mature green ‘Sharwil’ avocado Hawaii is currently not authorized 

by United States regulations 7CFR § 318.13, a pathway-initiated pest risk assessment (PRA) was 

prepared by APHIS’s Plant Protection and Quarantine (PPQ) to identify the unmitigated pest 

risks associated with importation of mature green ‘Sharwil’ avocado fruit from Hawaii (USDA, 

2011). 

The risk assessment identified the following quarantine pests as having a high unmitigated risk 

potential:

Bactrocera dorsalis (Hendel) (Diptera: Tephritidae)

The risk assessment identified the following quarantine pests as having a medium unmitigated 

risk potential:

Ceroplastes rubens Maskell (Hemiptera: Coccidae)

Coccus viridis (Green) (Hemiptera: Coccidae)

Cryptoblabes gnidiella Millière (Lepidoptera: Pyralidae)

Dysmicoccus neobrevipes Beardsley (Hemiptera: Pseudococcidae)

Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae)

Maconellicoccus hirsutus (Green) (Hemiptera: Pseudococcidae)

Nipaecoccus viridis (Newstead) (Hemiptera: Pseudococcidae)

Paracoccus marginatus Williams and Granara de Willink (Hemiptera: Pseudococcidae)

Planococcus minor (Maskell) (Hemiptera: Pseudococcidae)

Pseudococcus cryptus Hempel (Hemiptera: Pseudococcidae)

Since development of PRA in 2008, PPQ had the opportunity to review the status of certain pests 

associated with imported commodities. Based on that review, in April 2012, PPQ concluded that 

two pests listed above, Coccus viridis and Planococcus minor, no longer met our definition of 

quarantine pests and therefore required no regulatory actions (USDA, 2012a, USDA, 2012b).

APHIS-PPQ pest risk assessment guidelines (USDA, 2000) suggest that, for quarantine pests 

given an overall high risk potential rating, specific phytosanitary measures beyond standard portof-entry inspection are highly recommended to mitigate pest risk. This document outlines the 

phytosanitary measures that APHIS will require if the proposed interstate movement of ‘Sharwil’ 

avocados from Hawaii is approved. 

The proposed movement of fresh ‘Sharwil’ avocado fruit from Hawaii, if approved, would be 

regulated by amendment to existing fruit and vegetable domestic movement regulations (7 CFR 

§318.13). Pest risk management is the process of identifying ways to react to a perceived risk, 

evaluating the efficacy of these actions, and identifying the most appropriate options (IPPC, 

2004). This document outlines phytosanitary measures and provides evidence of their efficacy in
4

preventing the introduction of quarantine pests. The appropriate level of protection may be 

achieved through the application of a single phytosanitary measure, such as establishment of 

pest-free areas, pest free place of production or a quarantine treatment, or a combination of 

measures in a systems approach. The risk management measures proposed for ‘Sharwil’

avocados are combined into a systems approach. 

APHIS PPQ Oversight and Compliance Agreement

APHIS will develop a compliance agreement that details the activities that the growers will carry

out to meet the requirements of the systems approach. APHIS will be directly involved with the 

monitoring and auditing implementation of the systems approach. APHIS will ensure that each 

grower has a fruit fly trapping and control program and follows all requirements of this systems 

approach. The growers must maintain all forms and documents related to program activities in 

places of production for at least 1 year and, as requested, provide them to APHIS for review. 

Risk Management Measures

All measures listed below must be included for fruit shipped to the mainland. The movement of 

fresh ‘Sharwil’ avocado fruit from Hawaii will be done using a systems approach including the 

following risk management measures:

1. Orchard certification and Sharwil variety only. ‘Sharwil’ avocados must be grown in 

approved places of production (orchards) that are registered with APHIS. APHIS will 

approve all places of production and ensure they meet the requirements of the systems 

approach, including variety verification and tree canopy separation. APHIS will visit and 

inspect the places of production monthly, starting two months (60 days) before harvest and 

continuing until the end of the shipping season. 

2. Trapping for Bactrocera dorsalis. Growers must receive training on fruit fly trapping 

(University of Hawaii or APHIS) and conduct fruit fly trapping in the orchards for 

Bactrocera dorsalis (oriental fruit fly) with McPhail or multilure type traps at a rate of one

trap per 10 hectares (one trap per 24 acres) with a minimum of 2 traps per place of 

production. Trapping must be conducted beginning one month prior to harvest and continue 

through the end of the harvest period. Traps must be serviced on a weekly basis and number 

of trapped fruit flies recorded. Trap records must be maintained for at least one year and 

provided to APHIS upon request. 

3. Orchard Control for Bactrocera dorsalis. Control of fruit flies in the orchards using bait 

sprays will be required as long as oriental fruit flies are trapped above 0.4 ftd (fruit flies per 

trap per day). Controls must be repeated at 10-day intervals until the fruit fly population 

drops below 0.4 ftd or harvesting is completed. There is no set upper limit for the number of 

fruit flies trapped for shipping as long as orchard control continues. 

4. Orchard sanitation program. Culls must be removed from the harvest area of the orchard 

the day before each harvest.

5. Harvested at mature green stage with stems attached. ‘Sharwil’ avocados must be 

harvested only at the mature green stage with stems attached. Avocados must be hard ripe 

fruit. Fruit must not indent with moderate finger pressure and no part of the fruit shall be 

soft.
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6. Post harvest safeguards, including screened facilities. The packinghouse must be 

registered with APHIS. Within 12 hours of harvest ‘Sharwil’ avocados must be moved into a 

pest-exclusionary packinghouse. All openings to the outside of the packinghouse must be 

covered by screening with openings of not more than 1.5 mm or by some other barrier that 

prevents pests from entering. During the time the packinghouse is in use for shipping 

‘Sharwil’ avocados to the continental United States, the packinghouse may only accept fruit 

from registered, approved places of production. APHIS will audit packinghouse operations 

to verify that the packinghouses are complying with the requirements of the systems 

approach. If APHIS finds that a place of production or packinghouse is not complying with 

the requirements of the systems approach, no fruit from the place of production or 

packinghouse will be eligible for movement to the continental United States until APHIS 

conducts an investigation and appropriate remedial actions have been implemented. Fruit to 

be shipped to the continental United States must be packed for shipment in insect-proof 

cartons or containers (which can be sealed at the packinghouse against the entry of pests), or 

covered with insect-proof mesh or a plastic tarpaulin for transport to the continental United 

States. These safeguards must remain intact until arrival in the United States. 

7. Culling to remove damaged fruit and surface pests. Any fruit with stems detached must 

be removed before or during packing. Any overripe, soft, damaged or deformed fruit and 

fruits with surface pests must be culled. 

8. Sampling. A biometric sample of ‘Sharwil’ avocado fruit must be inspected by APHIS 

following any post-harvest processing. A biometric sample will be visually inspected for 

quarantine pests, and a portion of the fruit will be cut open to detect internal pests, including

Bactrocera dorsalis. Fruit may also be subject to inspection at port of arrival. If quarantine 

pests other than fruit flies are found, the entire lot of fruit will be prohibited from movement

into the continental United States unless it is treated with an approved quarantine treatment 

monitored by APHIS. If a single larva of any fruit fly is found in a shipment from a place of 

production (either by the APHIS in Hawaii or at the continental United States port of entry), 

the entire lot of fruit will be prohibited from export, and the place of production producing 

that fruit will be suspended from the interstate shipment program until APHIS conducts an 

investigation and appropriate remedial actions have been implemented.

9. Traceback. Box markings identifying each orchard will be required so that consignments 

can be traced back to orchards or places of production. 

10. Limited distribution only to 321northern-tier states and the District of Columbia. Box 

markings will also be required to indicate limited distribution. 

11. Limited harvest period only during winter months of November 1 to March 31. 

Consignments may only be harvested and shipped during this time period.

Efficacy of Risk Management Measures

A systems approach made up of multiple mitigations can provide an alternative to singlemeasure mitigation, such as a standalone quarantine treatment, to meet the appropriate level of 

 

1 Colorado, Connecticut, Delaware, 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, Washington, West 

Virginia, Wisconsin, Wyoming 
6

phytosanitary protection, or can be developed to provide phytosanitary protection in situations in 

which no single measure is available (IPPC, 2002). For example, Hass avocados from Mexico 

have been produced and exported to the United States under a systems approach for Stenoma 

catenifer, seed and stem weevils, and fruit flies for over eight years with no interceptions of 

quarantine pests (AQAS, 2011). The Mexican avocado program included a field program to 

maintain pest free and low pest prevalence areas. The systems approach combines field 

inspection for pests with cutting of samples at the packing house, and sampling by Customs and 

Border Protection at the first port of entry to the United States. Over a period of nine years from 

1998 to 2007 more than 27,000 avocados were sampled with no fruit fly larvae found (USDA, 

2007).

‘Sharwil’ avocado is a poor host to oriental fruit fly (Bactrocera dorsalis); several studies have 

shown that under normal conditions ‘Sharwil’ avocado does not become infested with oriental

fruit flies. Armstrong et al. (1983) showed that Hawaiian ‘Sharwil’ avocados at mature green 

stage with pedicel attached to the tree are not naturally infested with Mediterranean fruit, melon 

fly, and oriental fruit fly. They also reported the inability of gravid females to oviposit in mature 

green ‘Sharwil’ fruits under field and laboratory forced-infestation situations. However, 

Armstrong et al. (1983) also observed that fruits (two out of 189) punctured with a pin yielded 

infestations by oriental and Mediterranean fruit flies under caged conditions. Oi and Mau 

(1989) found no infestations of fruit flies in mature green ‘Sharwil’ avocados in the field in 

Hawaii. However, they reported oriental and Mediterranean fruit fly infestations in harvested 

mature green fruits exposed to flies in cage tests. Oi and Mau (1989) concluded that, while the 

probability of fruit fly infestations in mature green ‘Sharwil’ was unlikely under natural field 

conditions, the nature of resistance that this variety possesses does not ensure that infestation 

could not occur; thus, concluding that ‘Sharwil’ avocados are poor hosts of oriental and 

Mediterranean fruit flies. Further studies by Armstrong (1991) concluded ‘Sharwil’ avocado is 

not a host for Mediterranean fruit fly, melon fly, or oriental fruit fly infestations when the fruit is 

attached to the tree, or when fruits were harvested with stem (pedicel) attached and moved into a 

packinghouse facility within 12 hours after harvest, culled to remove damaged fruits, and packed 

in fly-proof boxes. Armstrong also reported the inability of solanaceous fruit fly, Bactrocera 

latifrons (Hendel), to infest ‘Sharwil’ avocados. 

Based on this research APHIS allowed ‘Sharwil’ avocado to be shipped from Hawaii to the 

mainland under a systems approach beginning in September 1990 (Liquido et al., 1995). In 

February 1992 oriental fruit fly larvae were found in fruit that was qualified for interstate 

shipment from Hawaii under the systems approach, and APHIS suspended the program based on 

these larval finds (Liquido et al., 1995). 

More research on ‘Sharwil’ avocado host status to fruit flies has been conducted. Liquido et al. 

(1995) surveyed for field infestation of fruit flies in mature green ‘Sharwil’ avocados in 1992 

and 1993 in response to a request from APHIS to determine the level of fruit fly infestations in

‘Sharwil’ avocados in Kona. Surveys were done in March-August 1992 and in September 1992 

– May 1993, with 5,004 samples, 4,888 of which were mature green fruits with pedicel firmly 

attached on the tree at the time of sampling. Out of 1,047 fruit samples collected between 2-10 

March 1992, four mature green fruits with pedicel firmly attached to the tree during sampling 

were infested with oriental fruit flies; only one of these infested fruit had no morphological 
7

aberration. During the 1992 field survey, the area was experiencing a severe drought, and the 

only infested samples were found in what were considered late-season fruits. All fruit samples 

during the September 1992 – May 1993 census had no fruit fly infestation. No Medflies or other 

species of fruit flies were found. Liquido et al. (1995) concluded that drought was the primary

cause of the breakdown of resistance mechanisms in ‘Sharwil’ avocados. Follett (2009) 

investigated puncture resistance of ‘Sharwil’ avocados, and Follett and Vargas (2010) proposed a 

modified version of the original systems approach which included several measures listed above. 

Klungness et al. (2009) found that fruit fly populations were consistently low in ‘Sharwil’ 

avocado orchards in Hawaii, and found only four larvae in two fruit from 489 fruit collected 

from the ground, both fruit from the same farm. This research suggests conditions that foster

infestation by fruit flies may be very localized and specific to certain areas and certain times.

The natural resistance of ‘Sharwil’ avocados to fruit fly infestation appears to break down with 

increase in fruit maturity or degree of ripeness and after harvest. Based on research by Liquido 

et al. (1995), ‘Sharwil’ avocados may become poor hosts of oriental fruit fly under certain field 

conditions that may include water stress and nutritional deficiencies. Specifically the failure in

the ‘Sharwil’ avocado program in 1991 involved unusual conditions which included soft fruit 

and uncontrolled fruit fly populations.

The system of risk management measures in this document is based on the original risk 

management measures from 1990 with the addition of new measures to prevent oriental fruit fly 

infested avocados from entering into the pathway of interstate movement. These additional 

measures include:

 Trapping program to monitor fruit flies

 Orchard control of fruit fly populations

 Avocados must be harvested at the hard green mature stage with the attached stem, and 

no soft fruit may be packed.

 Sampling of packed avocados will include cutting of some fruit to inspect for fruit fly 

larvae.

 Limited distribution of fruit in the United States

 Limited harvest period

APHIS will provide oversight to the systems approach through a compliance agreement that 

details the grower’s responsibilities. APHIS will ensure that each grower has a fruit fly trapping 

and control program and follows all requirements of this systems approach. 

The combination of leaf and fruit composition is unique to ‘Sharwil’ and is readily identifiable, 

so that an industry expert and a trained APHIS inspector can accurately certify orchards. 

Through a compliance agreement, APHIS will ensure that all export orchards ship only ‘Sharwil’ 

avocado.

High pest populations are a contributing factor to the failure of systems approaches. By

monitoring fruit fly populations using trapping and using orchard fruit fly controls, high 

populations are avoided. Fruit fly trapping and field control are standard procedures for most 

commodity export programs where the commodity may be subject to infestation by fruit flies. 
8

The trapping required here follows guidelines of the International Atomic Energy Agency 

(IAEA) on fruit fly trapping for low prevalence areas (FTDs for eradication programs are 

between 0.1 and 0.0; IAEA, 2003). The personnel conducting the trapping must be trained by

APHIS. APHIS will verify that places of production have effective fruit fly trapping programs, 

and follow control guidelines, when necessary, to reduce regulated pest populations. APHIS 

may monitor the places of production if necessary. Removal of fallen fruit prior to harvest 

contributes to the goal of preventing damaged and overripe fruit, which may possibly be infested, 

from being shipped to the continental United States. 

By only allowing hard green mature avocados with stems attached to be packed, there is an 

operationally measurable criterion for a fruit that may pose a pest risk. These fruit will be 

prohibited from entering the pathway. 

Limiting the harvest season will prevent overripe fruit from entering the pathway. Late in the 

harvest season, overripe fruit are more likely to be found in the orchard and might be picked by 

accident. The limited distribution will ensure that if any fruit with fruit flies make it through the 

system, there will be no hosts or climate conditions where they can reproduce.

‘Sharwil’ avocados produced under this systems approach will be inspected by APHIS PPQ as 

part of pre-departure clearance inspections in Hawaii. Infested consignments will be rejected,

and traceback will be done by APHIS to identify and correct problems including removal of the 

packinghouse and orchard from the interstate movement program. The sampling of fruit,

including cutting, will give warning if any portion of the systems approach is failing. 

Summary

There are several new risk management measures included in this systems approach directed 

against Bactrocera dorsalis and the other quarantine pests of concern that will permit the 

interstate movement of ‘Sharwil’ avocados from Hawaii while satisfying the appropriate level of 

phytosanitary protection for the rest of the continental United States. A systems approach, 

employing a combination of measures acting independently, if properly implemented, mitigates 

risk and provides an acceptable level of phytosanitary protection. 

Author

Walter Gould, Senior Risk Manager

APHIS-PPQ

References

AQAS. 2011. Agricultural Quarantine Activity System Pest Interception Database. USDAAPHIS-PPQ. Last accessed Sept. 2011.

Armstrong, J. W., C.W. Mitchell, and G. J. Farias. 1983. Resistance of ‘Sharwil’ avocados at 

harvest maturity to Infestation by three fruit fly species (Diptera: Tephritidae) in Hawaii. 

J. Econ. Entomol. 76:119-121.
9

Armstrong, J.W. 1991. ‘Sharwil’ avocado: quarantine security against fruit fly (Diptera: 

Tephritidae) infestation in Hawaii. J. Econ. Entomol. 84:1308-1315.

Follett, P.A. 2009. Puncture resistance in ‘Sharwil’ avocado to oriental fruit fly and 

Mediterranean fruit fly (Diptera: Tephritidae) oviposition. J. Econ. Entomol. 102:921-

926.

Follett, P. A., and R. I. Vargas. 2010. A systems approach to mitigate oriental fruit fly risk in 

‘Sharwil’ avocados exported from Hawaii. Acta Horticulturae 880: 439-445.

IAEA. 2003. Trapping guidelines for area-wide fruit fly programmes. International Atomic 

Energy Agency, Vienna, Austria. http://www.iaea.org/programmes/nafa/d4/index.html.

IPPC. 2002. The use of integrated measures in a systems approach for pest risk management. 

International Standards for Phytosanitary Measures No. 14. Rome: Secretariat of the 

International Plant Protection Convention, United Nations Food and Agriculture 

Organization.

IPPC. 2004. Pest risk analysis for quarantine pests, including analysis of environmental risks 

and living modified organisms. International Standards for Phytosanitary Measures No. 

11. Rome: Secretariat of the International Plant Protection Convention, United Nations 

Food and Agriculture Organization.

Klungness, L.M., R.I. Vargas, E.B. Jang, R.F.L. Mau, and K. Kinney. 2009. Susceptibility of 

ripe avocado to invasive alien fruit flies (Diptera: Tephritidae) on the island of Hawaii. 

Proc. Hawaiian Entomol. Soc. 41: 1-13.

Liquido, N.J., H.T. Chan, and G.T. McQuate. 1995. Hawaiian Tephritid Fruit Flies (Diptera): 

Integrity of the Infestation-Free Quarantine Procedure for 'Sharwil' Avocado. J. Econ. 

Entomol. 88: 85-96.

Oi, D. H. and R. F. Mau. 1989. Relationship of fruit ripeness to infestation in ‘Sharwil’ avocados 

by the Mediterranean fruit fly and the oriental fruit fly (Diptera: Tephritidae). J. Econ. 

Entomol. 82:556-560.

USDA. 2000. Guidelines for Pathway-Initiated Pest Risk Assessments, Version 5.02. USDAAPHIS, PPQ; http://oars.aphis.usda.gov/ppq/pra/commodity/cpraguide.pdf

USDA. 2007. Risk Management Document: Removal of Anastrepha Fruit Fly Trapping 

Requirements from Mexican ‘Hass’ Avocados for Importation into the United States. 

USDA-APHIS-PPQ. Dec. 13, 2007. 4 pp.

USDA. 2011. Qualitative Pathway-Initiated Risk Assessment for the Movement of Mature 

Green ‘Sharwil’ Avocado, Persea americana Mill. from Hawaii into Continental United 

States. USDA-APHIS-PPQ Center for Plant Health Science and Technology - Plant 
10

Epidemiology and Risk Analysis Laboratory. 86 pp.

USDA. 2012a. Official Control - The Federally Recognized State Managed Phytosanitary

Program. USDA-APHIS-PPQ Plant Health Programs.

http://www.aphis.usda.gov/plant_health/plant_pest_info/frsmp/non-reg-pests.shtml

USDA. 2012b. Removal of Coccus viridus and Planococcus minor. USDA-APHIS-PPQ 

National Identification Services. 

http://ppqersharepoint.we.aphis.gov/national/pspi/nis/Support%20Site%20Files/nispolici

es4.html
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Table 1. The mitigations that will be in the CFR 

or the Compliance Agreement (CA) or both.

Mitigationz CFR or CA or Both

1 Both, but will not include timing 

of orchard inspections in CFR

2 CA

3 CA

4 Both, but the timing of removal will

not be specified in the CFR, only in 

the CA.

5 Both

6 Both

7 CA

8 CA

9 CA

10 CA

11 CA

z

Enumerated in Risk Management Measures section