United States

Department of 

Agriculture

Risk Management Document

Importation of Live Greenhouse-Grown Tomato 

Plantlets (Solanum lycopersicum) in APHIS-Approved 

Growing Media from Mexico into the Continental 

United States

October 28, 2014

Ver. 1.17

USDA, Animal and Plant Health Inspection Service 

Plant Protection and Quarantine

Plant Health Programs 

Regulations, Permits and Manuals

Contact Person: Lydia Colón
Mexico Tomato PIGM RMD Ver. 1.16 October 9, 2014 2

Introduction

Plants in growing media imported into the United States must be approved by Umited States 

Department of Agriculture (USDA), Animal and Plant Health Inspection Service (APHIS) and 

must comply with all requirements under Title 7 of the Code of Federal Regulations (CFR), Part 

319.37-8 (CFR, 2013). Currently, under this regulation, the importation of tomato plantlets in 

growing media from Mexico into the continental United States is not authorized. Furthermore, 

as a result of a notice published in the Federal Register on April 18, 2013, tomato plants from all 

countries other than Canada are not authorized importation pending a pest risk analysis. APHIS 

conducted a pest risk assessment (PRA) in response to a request from the Servicio Nacional de 

Sanidad, Inocuidad y Calidad Agroalimentaria (SENASICA), the national plant protection 

organization (NPPO) of Mexico, for a change in Federal regulations to allow the entry of 

greenhouse-grown grafted tomato plantlets in growing media from Mexico for use in commercial 

greenhouse fruit production (USDA, 2013). The APHIS PRA identified and further analyzed 

seven pests that appeared to have a reasonable likelihood of being associated with live plantlets 

of Solanum lycopersicum:

Aleurodicus dispersus (Hemiptera: Aleyrodidae)

Bemisia tabaci (including biotypes B and Q) (Hemiptera: Aleyrodidae)

Trialeurodes vaporarium (Hemiptera: Aleyrodidae)

Liriomyza huidobrensis (Diptera: Agromyzidae)

Maconellicoccus hirsutus (Hemiptera: Pseudococcidae)

Paracoccus marginatus (Hemiptera: Pseudococcidae)

Thrips palmi (Thysanoptera: Thripidae). 

The PRA considered the likelihood and consequences of introducing these pests and indicated 

that all of the pests selected for further analysis received Negligible risk ratings for likelihood of 

introduction (i.e., entry plus establishment) into the endangered area via the import pathway. For 

pests receiving a Negligible risk rating, pest introduction is considered highly unlikely to occur 

given the exact combination of events required for successful introduction (USDA, 2012). In

reaching this finding, the PRA considered the effects of all greenhouse specifications described 

in supporting documents provided by the NPPO of Mexico (SAGARPA 2010, 2013). Those 

production/greenhouse specifications include:

 Tomato plantlet production follows strict sanitation protocols (SAGARPA, 2010)

 Plantlets used as rootstock and scion are started from certified seed germinated inside the 

greenhouses (SAGARPA, 2010).

 Water used in the greenhouse is either spring or well water and is disinfected with 

chlorine and ultraviolet light (SAGARPA, 2010). 

 Workers enter the greenhouse through sanitation stations (SAGARPA, 2010). 

 Greenhouse perimeter and all clean areas have double insect screening, including 

ventilation ports (SAGARPA, 2010). 

 Screen openings are small enough to exclude the entrance of thrips into the area, therefore 

also excluding aphids, whiteflies and larger Hemiptera (SAGARPA, 2013). 

 Greenhouses have automated sprinkling systems (SAGARPA, 2010).
Mexico Tomato PIGM RMD Ver. 1.16 October 9, 2014 3

 Insect traps near entrances and throughout the greenhouse are used to monitor the 

presence of insects – yellow to attract aphids and whiteflies and blue to attract thrips 

(SAGARPA, 2010, 2013).

 Biological control agents are released inside the greenhouses on a bi-weekly basis 

(SAGARPA, 2013).

 Insecticides are available for pest control in the event of pest presence – these include 

pyrethroids, neem extracts, insecticidal soaps, spinosad, sulphur and bacterial pesticides 

(SAGARPA, 2013).

As described in this Risk Management Document (RMD), APHIS has evaluated the pests 

described in the PRA (USDA, 2013) and determined that the requirements in 7 CFR 319.37-

5(r)(3) and 319.37-8 (CFR, 2013) will be effective in managing the risk associated with these 

pests. APHIS proposes to add Solanum lycopersicon from Mexico to the approved plants in 

7 CFR 319.37-8(e). 

Risk Management Measures

S. lycopersicum plants in growing media imported into the United States from Mexico must, at a 

minimum, comply with the requirements in 7 CFR 319.37-8, and all other requirements in 7 CFR 

319.37 including the requirements of 7 CFR 319.37-5(r)(3) (CFR, 2013) for restricted articles of 

Pelargonium spp. or Solanum spp. The requirements in 7 CFR 319.37-8 and 7 CFR 319.37-

5(r)(3) comprise “systems approaches” with a combination of integrated measures aimed at 

reducing pest risk. The International Plant Protection Convention (IPPC) defines a “systems 

approach” as, “The integration of different risk management measures, at least two of which act 

independently, and which cumulatively achieve the appropriate level of protection against 

regulated pests” (IPPC, 2010). Similarly, the Plant Protection Act of 2000 (PPA, 2000) defines 

a “systems approach” as “...a defined set of phytosanitary procedures, at least two of which have 

an independent effect in mitigating pest risk associated with the movement of commodities.”

The USDA Minimum Sanitation Protocols for Offshore Geranium Cutting Production (USDA, 

2007) provides the operational details for the systems approach described in 7 CFR 319.37-

5(r)(3).

As noted above, the PRA (USDA, 2013) considered procedures described in supporting 

documents provided by the NPPO of Mexico, and listed above (SAGARPA 2010, 2013), as 

mandatory. In addition to those procedures , APHIS has determined the pest risk management 

measures necessary for the importation of tomato plantlets in growing media from Mexico into 

the United States must include the following integrated pest risk management measures listed in 

7 CFR 319.37-8 and 7 CFR 319.37-5(r)(3): 

1. The NPPO of Mexico must enter into a bilateral workplan with APHIS setting out the 

conditions for producing and monitoring plant production and enforcement of the 

requirements of the regulations and;

2. The grower must enter into a written agreement with the NPPO of Mexico and agree to 

comply with the provisions of the regulations and to allow the NPPO access for 
Mexico Tomato PIGM RMD Ver. 1.16 October 9, 2014 4

monitoring inspections. The production site must be registered with and approved by both 

APHIS and the NPPO of Mexico. Shipments of exported tomato plantlets must be 

traceable back to the the production site where they originated;

3. After the initial approval, the production site must be inspected annually by APHIS 

and/or the NPPO of Mexico;

4. Plants must be grown in APHIS-approved growing medium which has not been used 

previously and is treated as described in USDA (2007) to ensure freedom from Ralstonia 

solanacearum race 3 biovar 2;

5. Growing media and the containers in which the plants are grown must be safeguarded 

from contact with potentially infested soil or media and must not come in direct contact 

with any water source such as a hose end or irrigation emitter;

6. Plants must be grown solely in pest exclusionary greenhouses that meet the following 

requirements:

 Sanitary procedures to exclude quarantine pests must always be employed, 

including the cleaning and disinfection of benches, floors and tools;

 Pest management measures, including monitoring for pests with yellow or blue 

sticky traps, must be applied to protect against quarantine pests. While in the 

greenhouse, plants must be treated with appropriate pesticides as needed to 

maintain a pest-free condition;

7. The greenhouse must be free from sand and soil;

8. Dicotyledonous weeds must be controlled inside the greenhouse;

 All vents and openings except entryways must be covered with screens having 

openings small enough to exclude arthropod pests including thrips1;

 Entryways must be equipped with automatic closing double doors;

9. Plants must be grown in a greenhouse unit that is used solely for articles grown in 

compliance with these regulations;

10. Greenhouses must be constructed in such a manner to prevent runoff water from 

surrounding areas to enter the greenhouse;

11. Greenhouses must be surrounded by a one meter buffer free of dicotyledonous weeds and 

sloped so that water drains away from the greenhouse;

 

1

7CFR§319.37-8 requires all vents and openings must be covered with screens having openings no greater than 0.6 

mm (30 mesh). However, SAGARPA (2013) states, “The tomato plantlets are grown in the dedicated nursery area 

that is fitted with screens on all openings. These screens are small enough to exclude the entrance of Thrips into the 

growing area, therefore also excluding the larger Hemiptera insects, aphids and whiteflies.” Because of thrips small 

size, a mesh size of 80 (0.177 mm opening) or smaller is required to restrict their entry into the greenhouse (Bethke, 

1994; Ghidiu and Roberts; Sood, 2010).
Mexico Tomato PIGM RMD Ver. 1.16 October 9, 2014 5

12. Plants must be grown solely from certified seeds germinated in the aforementioned pest 

exclusionary greenhouse;

13. Water must be derived from an APHIS-approved source and/or be treated by an APHISapproved method (USDA, 2007); water must be tested at least annually and found free

from Ralstonia solanacearum race 3 biovar 2;

14. Ebb and flow irrigation is not permitted and drip irrigation systems must be equipped 

with back flow preventers;

15. All equipment that comes in contact with S. lycopersicum plants must be sanitized so 

that R. solanacearum race 3 biovar 2 is not transmitted between plants or enter from 

outside the production site via the equipment;

16. Production site personnel must receive training to recognize and prevent the introduction 

of R. solanacearum race 3 biovar 2;

17. Production personnel must adequately sanitize clothing and shoes and wash their hands 

before entering the greenhouse;

18. Plants must be grown on benches supported by legs at least 46 cm above the floor;

19. Plants must be stored and packaged in areas free from soil, sand and quarantine pests;

20. Plants must be handled and packed to prevent the introduction of R. solanacearum race 3 

biovar 2 and labeled to identify the production site;

21. Plants must be inspected in the greenhouse and found free from evidence of quarantine 

pests by APHIS or the NPPO of Mexico no more than 30 days prior to export;

22. The production site must conduct ongoing testing for R. solanacearum race 3 biovar 2 

using an APHIS-approved testing protocol (USDA, 2007). Records must be kept and 

made available to APHIS and the NPPO of Mexico for two growing seasons;

23. Detection of R. solanacearum race 3 biovar 2 at the production site or in consignments 

from the production site will result in removal from export eligibility until reinspection 

determines the site is free from R. solanacearum race 3 biovar 2 and APHIS is satisfied 

all problems have been addressed; 

24. Consignments must be accompanied by a Phytosanitary Certificate with an Additional 

Declaration indicating the requirements of 7 CFR 319.37-5(a) [potato cyst nematode], 7 

CFR 319.37-5(r)(3) [Ralstonia] and 7 CFR 319.37-8 (e) [growing media] have been met.

25. In addition to the integrated pest risk management measures of 7 CFR 319.37-8 and 7 

CFR 319.37-5(r)(3), APHIS will require a signed Compliance Agreement between 
Mexico Tomato PIGM RMD Ver. 1.16 October 9, 2014 6

APHIS and the importing greenhouse. Stipulations within the Compliance Agreement 

will require periodic APHIS inspections of the facility and plant material while actively

growing in the importing greenhouse. Conditions of the compliance agreement include 

the following, as well as additional measures as deemed necessary by APHIS Officials in 

order to maintain phytosanitary protection of U.S. agriculture and the environment:

Importation/Notification/Transportation

 An importing greenhouse representative shall inform the APHIS Plant Protection 

and Quarantine (PPQ) State Plant Health Director (SPHD) (or their authorized 

designee) and the Plant Inspection Station (PIS) at least 24 hours prior to the 

arrival of the tomato plantlets.

 The tomato plantlets must be imported in sealed packaging. 

 The tomato plantlets must enter through a PIS. An APHIS inspector at the PIS 

will confirm that the shipment is accompanied by an official foreign phytosanitary

certificate. 

 The tomato plantlets must arrive with specified lot numbers or other 

distinguishable marks which will allow for any necessary traceback investigations 

by the NPPO of Mexico. 

 An APHIS inspector will conduct an inspection of the tomato plantlets. If found 

free of obvious pests, the packaging will be resealed and conditionally forwarded 

to the importing greenhouse under APHIS seal. 

 At the importing greenhouse, all shipping boxes and crates may only be opened by

trained facility staff within the confines of the approved importing greenhouse. 

All subsequent actions or handling of the tomato plantlets, (repotting, etc.) may

only be performed inside the importing greenhouse by trained facility staff.

 Plants or plant parts (e.g., prunings) may only be removed from the approved 

importing greenhouse for destruction on the premises with specific authorization 

and safeguarding instructions from a PPQ officer. Shipping boxes and crates may

be removed or discarded only with specific authorization and approved 

instructions from a PPQ officer. 



Pest Management

 Prior to importation, the facility manager of the importing greenhouse will 

provide a pest management plan to APHIS for review and approval.

 Any pest detections by facility personnel within the greenhouse will require 

immediate notification of the APHIS PPQ SPHD. 

 Any pest detections or symptoms of infestation found on plant material by the 

facility personnel must be preserved and submitted for review by a PPQ officer

who will obtain an official identification of the pest or assess the need for further 

action.

 The approved importing facility shall take steps to contain the pests as soon as 

detected.

 Upon the detection of any quarantine significant pests by the facility personnel, 
Mexico Tomato PIGM RMD Ver. 1.16 October 9, 2014 7

the greenhouse should be sealed and no entry permitted until authorized by

APHIS and the State Plant Regulatory Official (SPRO).

Production

 The imported tomato plantlets will be used only for fruit production. No increase 

of these plants by cuttings, grafting, suckers, flowers, seeds or air layers is 

authorized; distribution of the imported tomato plantlets beyond the confines of 

the importing facility is prohibited.

Facility Inspections and Audits

 PPQ will inspect the greenhouse, the imported tomato plantlets, and the 

surrounding area for any evidence of pests of quarantine significance to the United 

States. PPQ will also perform paper and operational audits to verify compliance 

with the stipulations outlined in the signed Compliance Agreement for this 

program.

 PPQ will inspect the importing greenhouse within one week of the arrival of the 

tomato plantlets and prior to the first fruit harvest.

 PPQ may conduct additional periodic inspections during the production cycle for 

each lot of tomato plantlets.

 If pests are found, APHIS shall consult with the authorized facility manager to 

determine the appropriate action to take based on the circumstances and the type 

of pest detected.

 If actionable pests are discovered, the level of contamination will be assessed by

PPQ, taking into consideration the segregation and safeguarding of various 

sections with the facility. This may result in the need to destroy part or all of the 

importing greenhouse plant material.

 Plants infested with actionable pests shall be incinerated, heated to 170° F for 30 

minutes or otherwise destroyed by methods approved by APHIS. However, any

finding of pests or pest damage would be preserved until the PPQ officer can 

obtain an official identification of the pest or assess the need for further action.

A discussion of the applicability and efficacy of the various measures that are required by

7CFR§319.37-8, 7CFR§319.37-5(r), measures indicated by the NPPO of Mexico (SAGARPA, 

2010, SAGARPA, 2013) and identified in the PRA (USDA, 2013) as mandatory and additional 

measures required by APHIS for this request is found below.
Mexico Tomato PIGM RMD Ver. 1.16 October 9, 2014 8

Selected Evidence for the Efficacy of Risk Management Measures

The efficacy of measures required for risk management on S. lycopersicum plantlets in growing media from Mexico is summarized in 

Table 1. 

Table 1. Efficacy of risk management requirements for S. lycopersicum plantlets in growing media from Mexico (number in 

parentheses refers to mitigations list above)

Measure(s) Pests Efficacy

Written compliance agreements

(1, 2)

All pests The NPPO of the producing country must enter into a bilateral workplan 

with APHIS setting out the conditions for producing and monitoring plant 

production and enforcement of the requirements of the regulation. 

Likewise, the production facility must enter into a compliance agreement 

with the producing country NPPO. Improper production and handling 

practices are often the primary means by which pests are introduced and 

spread in the place of production. The phytosanitary written agreements 

and administrative measures included in 7CFR§319.37-8 and 

7CFR§319.37-5 (r)(3) provide additional phytosanitary quality control and 

rigor over other measures, and reduce the possibilities of improper 

practices being employed. These measures are standard for many export 

programs and assist in maintaining quality of the program.

Registered places of production

(2)

All pests Places of production are registered to effectively maintain quality control 

and traceback.

Traceability (2) All pests Labelling of consignments to allow traceback is required. Traceback is 

effective at removing problem places of production from the systems 

approach. 7CFR§319.37-5 (r)(3) requires removal of export eligibility of a 

facility in the event of the detection of Ralstonia at the in consignments. 

Traceback enables the identification of the problem facility.

Annual facility inspection (3) All pests Requiring an annual inspection of each registered facility by APHIS and / 

or the NPPO of Mexico ensures compliance with written workplans and 

compliance agreements which, in turn, helps ensure that U.S. import 

requirements are met.
Mexico Tomato PIGM RMD Ver. 1.16 October 9, 2014 9

Table 1. Efficacy of risk management requirements for S. lycopersicum plantlets in growing media from Mexico (number in 

parentheses refers to mitigations list above)

Measure(s) Pests Efficacy

Grown in sterilized APHISapproved growing media (4, 5)Ralstonia solanacearum

Liriomyza huidobrensis

Thrips palmi

7CFR§319.37-5 (r)(3) requires that growing media must be free of R. 

solanacearum and must be an APHIS approved growing medium as listed 

in 7CFR§319.37-8 (e)(1). SAGARPA, 2010 indicates that tomato plantlets 

will be grown in peat and rock wool; both are approved media. The USDA

Minimum Sanitation Protocols for Offshore Geranium Cutting Production

(USDA, 2007) further requires that the growing media be sterilized by

steam or fumigation.

The use of new, sterilized growing media reduces the risk of introducing 

Liriomyza pupae into the crop (Bethke, 2010). Soil sterilization, including 

steam and methyl bromide are effective in controlling soil inhabiting pupae 

of Liriomyza (Cheek, 1999). Soil sterilization will kill immature thrips that 

are pupating in the soil (Shipp et al., 1991).

In general, using sterile or sterilized growing media reduces the likelihood 

of crop infestation by soil-dwelling pest life stages (Cheek, 1999).
Mexico Tomato PIGM RMD Ver. 1.16 October 9, 2014 10

Table 1. Efficacy of risk management requirements for S. lycopersicum plantlets in growing media from Mexico (number in 

parentheses refers to mitigations list above)

Measure(s) Pests Efficacy

Sanitation (disinfection of 

surfaces, equipment,etc.; 

removal of plant debris, sand, 

soil, weeds) (5, 6, 7)

All pests Sanitation and exclusion are highly effective in controlling most pests

(Dreistadt, 2001). “Strict adherence to good sanitation practices is 

essential to the management of bacterial diseases” (Dicklow, 2013).

SAGARPA (2010) provides general information indicating that grafting 

areas will be disinfected regularly and that grafting benches are equipped 

with disinfectant for tools.

The APHIS Minimum Sanitation Protocols for Offshore Geranium Cutting 

Production (USDA, 2007) requires that greenhouse floors be maintained 

free of debris and weeds and floors must drain properly to prevent 

puddling. Plant material (cuttings, trimmings, etc) that falls to the floor 

should not be retrieved by greenhouse workers who are in the process of 

handling production stock plants; it should be removed on a periodic basis 

(minimum weekly) and disposed of by other workers or by same workers 

after harvesting of cuttings is completed. Floors are to be sanitized at 

least once annually when greenhouses are cleared of stock production 

plants or before they are set up for the next growing season. Furthemore, 

the protocol requires surfaces upon which plants are grown should be 

disinfested prior to use and constructed so water draining from pots does 

not make contact with other pots. Greenhouse equipment used to make 

grafts or cuttings or used for other functions involving contact with plants

is to be surface disinfested prior to and between use on each plant or 

container. Alternatively, a set of knives can be assigned to a specific 

bench and rotated and disinfected between each plant. Carts and 

collection baskets are to be sprayed with a surface disinfectant on all 

surfaces that are likely to come into contact with plants or equipment used 

in processing plants. Equipment (knives, etc) used to harvest cuttings is 

to be soaked in surface disinfectant when not in use.

Liriomyza larvae remain inside the leaf onto which they hatched until they

pupate. After feeding, mature larvae exit the leaf and drop to the ground 

to pupate. Pupae can remain viable in the soil or substrate for several 

months at low temperatures and cause re-infestation in the following crop. 

Sanitizing floors, benches or areas underneath benches lowers the 

potential for these areas to harbor pupae. Regular, rapid removal of plant 

debris prevents the continuing development of foliar stages of pests such 

as Liriomyza spp. on excised leaves (Cheek, 1999).
Mexico Tomato PIGM RMD Ver. 1.16 October 9, 2014 11

Table 1. Efficacy of risk management requirements for S. lycopersicum plantlets in growing media from Mexico (number in 

parentheses refers to mitigations list above)

Measure(s) Pests Efficacy

Yellow and blue sticky traps in 

the greenhouse monitored on a 

regular basis, at least weekly (6)

L. huidobrensis

T. palmi

Sticky traps are an efficient tool for monitoring early infestations of thrips 

(Brødsgaard, 1989).

In addition to monitoring plants for Liriomyza feeding and oviposition 

damage (stippling) and for the presence of small mines on plants, sticky

traps are used for detection of leafminer activity. Yellow sticky cards are 

the best detection method for monitoring populations of adult activity

(Bográn, 2005; Weintraub and Horowitz, 1996).

Required pest management 

plan. While in the greenhouse, 

plants must be treated with 

appropriate pesticides as 

needed to maintain a pest-free 

condition (6)

Arthropods A comprehensive pest management plan must be implemented, and must 

include monitoring, inspections for signs of infestation, and targeted pest 

control as appropriate. Information gathered from scouting is used to 

select and schedule appropriate control tactics (Bethke, 2010). The pest 

management plan must be approved by the NPPO, and if treatments are 

required, these must be approved and prescribed by the NPPO.

All vents and openings are 

covered with screen (8)

Arthropods 7CFR§319.37-8 requires all vents and openings must be covered with 

screens having openings no greater than 0.6 mm (30 mesh). This mesh 

size is small enough to exclude leafminers (Bethke, 1994). Adult 

Liriomyza flies are 1-3 mm in length with a wingspan of about the same 

dimensions (CABI, 2014). Adults are excluded by greenhouse screens 

with an opening of 0.6 mm or smaller (Bethke, 1994; Bethke et al., 1994; 

Bográn, 2005). While 0.6 mm mesh will not exclude the other smaller 

arthropod pests (e.g., aphids, whiteflies, thrips) they may provide some 

limited discouragement to their entry. Mesh hole size does not 

necessarily correspond with degree of exclusion (Bell and Baker, 2000).

However, SAGARPA (2013) states, “The tomato plantlets are grown in the 

dedicated nursery area that is fitted with screens on all openings. These 

screens are small enough to exclude the entrance of Thrips into the 

growing area, therefore also excluding the larger Hemiptera insects, 

aphids and whiteflies.” Because of thrips small size, a mesh size of 80 

(0.177 mm opening) or smaller is required to restrict their entry into the 

greenhouse (Bethke, 1994; Ghidiu and Roberts; Sood, 2010). We are 

specifying mesh screen to be used in conjunction with a pest 

management program to ensure that no thrips (or other arthropods) will 

move with tomato plantlets.
Mexico Tomato PIGM RMD Ver. 1.16 October 9, 2014 12

Table 1. Efficacy of risk management requirements for S. lycopersicum plantlets in growing media from Mexico (number in 

parentheses refers to mitigations list above)

Measure(s) Pests Efficacy

Entryways equipped with 

automatic closing double doors

(8)

Arthropods Automatic closing double doors create a plant free area that workers must 

pass through reducing the likelihood that pests will enter the growing area 

(Dreistadt, 2001).

Plants grown in a greenhouse 

unit used solely for articles 

grown in compliance with these 

regulations (9)

All pests Avoiding comingling reduces the likelihood of contamination.

Greenhouse constructed to 

prevent water entry (10)

R. solanacearum race 3 biovar 2 Runoff surface water from fields or waterways with infected weed or crop 

hosts can carry Ralstonia (Wenneker et al., 1999). USDA (2007) requires 

that greenhouses are constructed in a manner to prevent contaminated 

runoff from entering production areas.

One meter buffer free of dicot 

weeds around greenhouse (11)

All pests Sanitation including the removal of weeds from inside and outside

greenhouses is an important cultural practice for preventing whitefly

infestations within greenhouses (Shipp et al., 1991). Leafminers feed on 

a large variety of plant species including weeds, keeping greenhouses 

and areas outside the greenhouse free of weeds, which can serve as 

reservoirs for leafminer populations and exclusion of immigrating adults is

valuable as a cultural control (Bethke, 2010).

Grown from certified seed 

germinated in the greenhouse

(12)

R. solanacearum race 3 biovar 2

(and other seed pathogens)

7 CFR 319.37-8 requires that plants are grown from seed germinated in 

the pest exclusionary greenhouse. SAGARPA (2012) and the PRA 

(USDA, 2013) indicate that certified seed will be obtained from several 

multinational sources but does not specify what pathogens the seed will 

be certified as free from. SAGARPA (2010) further states that the seed 

will be disinfected to remove seed transmitted bacterial pathogens.

Water from an APHIS-approved 

source treated by an APHIS 

approved treatment (13)

R. solanacearum race 3 biovar 2 The 7CFR§319.37-5 (r)(3) requirement for treatment of irrigation water is 

dependent upon its source and the water storage and delivery system in 

use. Water treatment is not required for irrigation water collected from 

deep wells which are properly sealed and where the water is used directly

or stored in tanks with no opportunity for contamination of the water 

supply by native soil or plant material/debris, or from municipal water 

directly from the municipal water system. SAGARPA (2010) states water 

used in the greenhouse is either spring or well water and is disinfected 

with chlorine and ultraviolet light. The treatment method used must be 

equivalent to the treatments described in USDA (2007).
Mexico Tomato PIGM RMD Ver. 1.16 October 9, 2014 13

Table 1. Efficacy of risk management requirements for S. lycopersicum plantlets in growing media from Mexico (number in 

parentheses refers to mitigations list above)

Measure(s) Pests Efficacy

No ebb and flow irrigation; 

backfow preventers; no emitters 

or hose ends contact with soil

(14)

R. solanacearum race 3 biovar 2 Ralstonia is a soilborne pathogen may be spread in contaminated soil, 

runoff and irrigation water (Hayward, 1991; Wenneker et al., 1999). 

Prohibition of ebb and flow irrigation and contact between emitters or hose 

ends and soil as well as the use of backflow prevention valves reduce the 

possibility of introducing Ralstonia and are required by 7CFR§319.37-5 

(r)(3) (USDA, 2007).

Equipment that comes in 

contact with S. lycopersicum

plants must be sanitized (15)

R. solanacearum race 3 biovar 2 See “Sanitation” above

Worker training (16) All pests 7CFR§319.37-5 (r)(3) requires that production site personnel receive 

training to recognize and prevent the introduction of Ralstonia. Mandatory

training decreases the likelihood that personnel will participate in activities 

that might introduce pests into the facility and, in the event of an 

introduction, will increase the likelihood that they will recognize pest 

symptoms and take appropriate action. SAGARPA, 2010 states that the 

production facility in Mexico “has continuous training of supervisors and 

workers to assure that they receive continuous education and qualification 

about sanitation protocols and practices...supervision personnel 

has...basic knowledge on pest identification.”

Worker hygiene (17) R. solanacearum race 3 biovar 2 SAGARPA (2010) provides a general description of the worker hygiene 

system in the production greenhouses. The infrastructure is designed to 

limit access and to force the flow of the people through a series of stations 

and processes for disinfection including a grate to eliminate the debris 

from shoes; a laundry to wash uniforms; an area to store personal 

belongings so they do not enter the greenhouse; dedicated footwear that 

is disinfected upon entry; handwashing station; an entryway that can only

be opened by placing hands in a disinfectatnt bath to reach the release 

button; a dressing area with dedicated coveralls. This generally follows 

the requirements of 7CFR§319.37-5 (r)(3) as outlined in USDA, 2007.

.

Grown on benches at least 46 

cm high (18)

R. solanacearum race 3 biovar 2 Growing plants on raised benches is another measure to prevent contact 

of production plants with runoff, soil, debris or other potentially

contaminated materials.
Mexico Tomato PIGM RMD Ver. 1.16 October 9, 2014 14

Table 1. Efficacy of risk management requirements for S. lycopersicum plantlets in growing media from Mexico (number in 

parentheses refers to mitigations list above)

Measure(s) Pests Efficacy

Stored and packaged in areas 

free from soil, sand and 

quarantine pests (19)

All pests See “Sanitation” above

Plants handled to prevent the 

introduction of R. solanacearum;

labeled to identify the production 

site (20)

R. solanacearum race 3 biovar 2 See “Sanitation” and “Registered places of production” above

Inspected in the greenhouse 

and found free from evidence of 

quarantine pests by an APHIS 

inspector or an inspector of the 

NPPO of Mexico, no more than 

30 days prior to the date of 

export to the United States (21)

All pests Phytosanitary inspections are widely recognized as an important part of a 

pest management program (Kahn and Mathur, 1999). Many insects, 

mites and pathogens have visible stages and symptoms that are readily

detected upon inspection. Inspection is the foundation of pest exclusion 

used by APHIS to prevent pests from entering the United States.

Adult Liriomyza females feed on leaf tissues resulting in a stippled or 

speckled appearance when they puncture the leaf surface with their 

ovipositors. Females also puncture leaf tissue to lay their eggs. Larvae 

feed on leaf tissue creating a serpentine leaf-mine. The mines gradually

increase in size as larvae feed and grow (Bográn, 2005). 

Stippling and leaf mines are readily detected by plant inspection. Careful 

inspection of all plant material before it is brought into the greenhouse 

and destruction of any infested plants helps to exclude leafminers. The 

European and Mediterranean Plant Protection Organization (EPPO) has 

recommended inspection of plants for planting at least every month as a 

means to prevent the spread of Agromyzidae leafminers in exported 

plants (CABI, 2014). 
Mexico Tomato PIGM RMD Ver. 1.16 October 9, 2014 15

Table 1. Efficacy of risk management requirements for S. lycopersicum plantlets in growing media from Mexico (number in 

parentheses refers to mitigations list above)

Measure(s) Pests Efficacy

Regular testing of each lot for 

Ralstonia (22, 23)

R. solanacearum race 3 biovar 2 All plant material must be free of Ralstonia solanacearum. The sampling 

protocol and diagnostic methods must be approved by APHIS. Records 

of disease testing are to be maintained and made available to APHIS 

upon request. In addition, plants are scouted regularly for signs of wilt, 

and tested for R. solanacearum as necessary. All plants that are to be 

discarded must be tested prior to destruction. Where positive results are 

attained, all plants in the greenhouse are to be destroyed, and the 

greenhouse decontaminated. The infested facility is to be quarantined, 

until such time that APHIS and the Mexican NPPO are satisfied that the 

infestation has been eliminated (USDA, 2007).

Consignments accompanied by

a Phytosanitary Certificate 

indicating the requirements of 7 

CFR 319.37-5(a) [potato cyst 

nematode], 7 CFR 319.37-

5(r)(3) [Ralstonia] and 7 CFR 

319.37-8 (e) [growing media] 

have been met (24)

All pests Provides assurance that NPPO has verified that plants in any given 

consignment have been produced in accordance with the cited 

regulations. “Phytosanitary certification is used to attest that consignments 

meet phytosanitary import requirements and...contributes to the 

protection of plants, including cultivated and uncultivated/unmanaged 

plants and wild flora (including aquatic plants), habitats and ecosystems in 

the importing countries.” (IPPC, 2011)

Safeguarding of plants during 

importation and transportation

(25)

All pests As noted above, sanitation and exclusion are highly effective in controlling 

most pests (Dreistadt, 2001). “Strict adherence to good sanitation 

practices is essential to the management of bacterial diseases” (Dicklow, 

2013).

Growth and inspection of 

imported plants under 

compliance agreement (25)

All pests Phytosanitary inspections are widely recognized as an important part of a 

pest management program (Kahn and Mathur, 1999). Postentry

inspection will provide additional opportunity to detect pests that develop 

as the plant matures from the very young age and stage of development 

at the time of import. Growth under compliance agreement will provide 

safeguards on the production ofplants, and, in the unlikely event of a pest 

detection, will ensure that the plants are disposed of in a manner that 

does not result in dissemination of pests. 

Growth under compliance agreement will also ensure that fruit from the 

plantlets that is moved from the nursery for commercial distribution does 

not disseminate plant pests.
Mexico Tomato PIGM RMD Ver. 1.16 October 9, 2014 16

Summary

APHIS concludes that commercial shipments of grafted tomato plantlets established in APHISapproved growing media produced using the integrated pest risk management measures 

described in the preceding section of this document in Mexico may safely be imported into the 

continental United States for the intended use of commercial fruit production without the risk of 

introducing Ralstonia solanacearum race 3 biovar 2 or the seven arthropod pests noted above or 

other pests of quarantine significance as listed in the PRA conducted to inform this market access 

request (USDA, 2013). Most of the measures included in this risk management document are 

already required by APHIS for importation of other plants in growing media. Additionally, if the 

measures listed above are adhered to, there is a negligible risk of tomato fruit from such plantlets 

introducing pests of quarantine significance into the United States. 

Authors 

W. Gould

Senior Risk Manager, Regulations, Permits and Manuals

C. Marasas

Senior Risk Manager, Regulations, Permits and Manuals

E.V. Podleckis

Senior Risk Manager, Regulations, Permits and Manuals

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