Filename: US reply to MBTOC on CA strawberry fruit Page 1

NOMINATING PARTY: The United States of America

DATE: AUGUST 29, 2013

BRIEF DESCRIPTIVE TITLE: Response to questions from MBTOC bilateral of June 26, 

2013 on strawberry fruit

SITE NAME (OPEN FIELD): Strawberry Fruit 

NOMINATING PARTY CONTACT DETAILS:

Contact Person: Federico San Martini, Ph.D.

Title: Policy Advisor

Address: Office of Environmental Policy

U.S. Department of State

2201 C Street, N.W. Room 2657

Washington, D.C. 20520 U.S.A.

Telephone: (202) 647-3819

Fax: (202) 647-1052

E-mail: SanMartiniFM@state.gov

CONTACT OR EXPERT(S) FOR FURTHER TECHNICAL DETAILS:

Contact/Expert Person: Yu-Ting Guilaran 

Title: Acting Director 

Address: Biological and Economic Analysis Division

Office of Pesticide Programs

U.S. Environmental Protection Agency

1200 Pennsylvania Avenue, N.W. Mailcode 7503P

Washington, D.C. 20460 U.S.A.

Telephone: (703) 308-0052 

Fax: (703) 308-7042 

E-mail: Guilaran.Yu-Ting@epa.gov

Strawberry Fruit

The United States is requesting that MBTOC recommend the full amount requested of 373,660 

kg for strawberry fruit for the U.S. Critical Use Nomination for 2015. We have been working 

closely with this industry sector for a number of years on their transition and, as you know, they 

face a range of barriers to phasing out methyl bromide, in particular given the overlapping State 

and Federal regulations that apply to alternatives. Nevertheless, we believe that this sector will 

be able to fully phase out of methyl bromide by 2017 to allow time to ensure the successful 

adoption of alternatives. The U.S. government is willing to commit to ensuring that the phaseout of controlled uses of methyl bromide for California strawberries will be completed by the 

end of 2016 (in other words, that 2016 will be the last use year for which we intend to request a 

methyl bromide CUE for this sector). It is vital that MBTOC recommend CUEs for these final 
Filename: US reply to MBTOC on CA strawberry fruit Page 2

two years to ensure we can make the transition we need to without putting growers out of 

business simply because they were not allowed enough time to fully complete the transition.

A transition time to 2017 is needed because, despite the recently approved higher use rates of 

chloropicrin, the regulatory landscape California strawberry growers face is uncertain. In 

particular , there are pending label changes that have been proposed by the California 

Department of Pesticide Regulations (Cal DPR) this year to the two key methyl bromide 

alternatives in California, chloropicrin and 1,3-dichloropropene. We anticipate that those 

regulations will be finalized next year or in 2015. The lack of a clear understanding by growers 

of when and how they can use these alternatives will hamper the ability of growers to transition 

more quickly to the alternatives than envisioned in our transition plan.

Furthermore, we believe this transition plan will ensure that sufficient time is available for 

practices and procedures to be developed, refined, and tested so that growers can use 

chloropicrin at these higher rates safely and effectively. The final transition will provide time to 

develop standard procedures for high rates of chloropicrin targeting Macrophominia or 

Fusarium; control of these pests is still causing significant difficulties and loss of crops in 

California at this time. This will also allow additional development of practices using straight 

chloropicrin to ensure consistent performance on different soil types, soil temperatures, pest 

pressure, and other conditions. The additional time will also be used to develop educational 

materials to help growers choose the appropriate fumigant alternative(s) within the California 

regulatory constraints, select the appropriate cultivar when single or multiple pathogens are 

present, as well as develop better sampling and identification processes when pathogens are first 

discovered in fields. Work continues to be conducted to test for strawberry cultivars that are 

resistant to the different plant pathogens present in strawberry fields, and we believe this work 

will continue to reduce the need for methyl bromide. The California Strawberry Commission 

has supported research for many years on non-fumigant production systems such as the raised 

bed trough system and anaerobic soil disinfestation with the ultimate goal of producing a high 

quality fruit without the need for fumigants. Such work will continue but, as MBTOC knows, 

the results to date with some of these approaches have revealed significant challenges.

We agree with MBTOC that chloropicrin has been in use commercially in California for a long 

time. However, as noted above, practices and procedures need to be developed so that the high 

use rates needed to control the key pests are effective. Furthermore, time is needed to 

demonstrate that high rates of chloropicrin are effective against Macrophominia or Fusarium.

Researchers in California plan to collect data this fall on the effectiveness of chloropicrin at the 

higher use rates on fields infested with Macrophominia or Fusarium. The higher rates that are 

needed to ensure control in fields with high pest pressures—the fields with critical needs 

addressed by our nomination—have only recently been approved. A recommendation from 

MBTOC for the full amount of methyl bromide for use in 2015 will put California strawberry 
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growers on a path to successfully transition to alternatives and complete the methyl bromide 

phase-out sector by the end of 2016. 

The U.S. government would like to thank MBTOC for our bilateral meeting in the margins of the 

33rd Open-Ended Working Group. During that bilateral meeting, MBTOC asked the U.S. 

delegation a number of questions. We have reproduced and answered those questions below.

1. Question from MBTOC - In the bilateral meeting between MBTOC and the California 

Strawberry commission Edgar Kelly (strawberry grower in Ventura County, CA) stated that 

he had failures when using straight chloropicrin on his farm. Could you describe any 

problems providing pathogen control using straight chloropicrin in California? 

U.S. Reply: The following table lists strawberry fruit fields in Ventura County, CA, where 

straight chloropicrin was tested and did not provide season-long control of crown and root 

pathogens. 

Table 1. Performance of straight chloropicrin in Ventura County, CA. 

Year Field Rate of chloropicrin Impact on crop (cultivar)

2010 Ramelli BLK 1 28 gal/ac. Inline (strip trt) w/ 

VIF

60% of crop was dead by mid-May (San 

Andreas cultivar)

2010 Ramelli BLK 2 28 gal/ac. Inline (strip trt) w/ 

VIF

90% of crop was dead by mid-May (San 

Andreas)

2011 Ramelli BLK 1 200 lbs/ac. Pic broadcast w/TIF 30% dead by mid-May (San Andreas)

2011 Ramelli BLK 2 300 lbs/ac. Pic broadcast w/TIF 25% dead by mid-May (Ventana)

2012 Ramelli BLK 1 350 lbs/ac. Pic broadcast w/TIF 25% dead by mid-May (San Andreas)

2012 Ramelli BLK 2 350 lbs/ac. Pic broadcast w/TIF 30% dead by mid-May (San Andreas)

2013 Ramelli BLK 1 350 lbs/ac. Pic broadcast w/TIF Yet to be planted (planted Oct 2013)

2013 Ramelli BLK 2 350 lbs/ac. Pic broadcast w/TIF Yet to be planted (planted Oct 2013)

The United States government is working to understand why these failures occurred. We 

believe that as practices and procedures are developed, refined and tested, growers will be 

able to use chloropicrin at the high rates listed in Table 1 to effectively control pests. 

However, some time is needed for growers to complete the process and, as noted above, 

significant challenges remain. 

2. Question from MBTOC - Anaerobic soil disinfestation (ASD) works very well in Morocco. 

What types of experiences have the California strawberry growers had with ASD? 

U.S. Reply: We have had generally good results with ASD but have not seen it to be 

effective in controlling Fusarium wilt in two separate experiments. Below is a picture of the 

field trials at Monterey Bay Academy with ASD treatments. While initially the ASD 

treatment appeared to be effective, that effectiveness declined after two years. All treatments 
Filename: US reply to MBTOC on CA strawberry fruit Page 4

have plants collapsing with Fusarium wilt with year-after-year ASD treatments (personal 

communication, D. Legard). 

Figure 1. Damage from Fusarium in Anaerobic Soil Disinfestation trials at Monterey Bay 

Academy, California. 

Photo courtesy D. Legard 2013

Figure 2. Additional damage from Fusarium in Anaerobic Soil Disinfestation trials at 

Monterey Bay Academy, California (ASDRB9 = 9 tons rice bran/acre). 

Photo courtesy D. Legard 2013
Filename: US reply to MBTOC on CA strawberry fruit Page 5

The United States is encouraged by further research work the California Strawberry 

Commission is conducting on ASD as well as other non-fumigant pest control methods. In 

particular, we would like to highlight the work of the “Nonfumigant Strawberry Production 

Working Group.” This group will continue its work to develop non-fumigant alternatives, 

and we are relying on this type of work to help us complete our transition by the end of 2016.

3. Question from MBTOC - Is there any additional data on the efficacy of metam-sodium for 

pathogen control in California?

U.S. Reply: Husein Ajwa (personal communication) reports that in experiments over 630 

lbs/ac of Na-methyldithiocarbamate were needed to control Macrophomina phaseolina. 

This is equivalent to 150 gal/ac of metam sodium (1 gal of metam-Na contains 4.22 lbs a.i). 

These results are from laboratory dose-response experiments using infested plant materials 

placed in 250 g soil in closed jars over 24 hours at 22 oC. The actual LC90 was over 4300 

umol a.i/kg soil. These rates are substantially higher than those permitted in California.

The paper published by Aida Zveibil (Israel) showed results from studies conducted at 50

oC under solarization, which is much hotter than the 22 oC that is representative of 

California strawberry growing conditions. The work from Israel relies heavily on soil 

bioassays. There is no method that can determine Macrophomina in soil due to 

interferences. Husein’s lab spent 1 year trying to replicate the Israeli results but could not 

get the isolation method to work under local conditions. 

4. Question from MBTOC - Is Pic-Clor 80 registered in the United States or California?

U.S. Reply: Pic-Clor 80 is not registered in the United States or California and was not 

considered in calculating the Telone (1,3-dichloropropene) township caps.

5. Question from MBTOC - Does the United States have additional data on Telone (1,3-

dichloropropene) in terms of efficacy with shank applications, or changes in the regulations?

U.S. Reply: There is no additional information on Telone performance or regulations at 

this time.

6. Question from MBTOC - If the California Department of Pesticide Regulation reregistration 

proposal for chloropicrin has elements that are less restrictive than the US EPA Federal label 

what would happen? 
Filename: US reply to MBTOC on CA strawberry fruit Page 6

U.S. Reply: In the United States, state and local pesticide regulators can place additional 

restrictions on the use of a pesticide without additional approval from the EPA. However, to 

be less restrictive (e.g. smaller buffer distances than the EPA level) the EPA would have to 

be consulted and approve those changes. 

7. Question from MBTOC - How would the allocation rule be used to reduce the amount of 

methyl bromide produced during the year of the critical use nomination if the Cal DPR 

regulations become less restrictive in how chloropicrin can be used? 

U.S. Reply: In each year’s allocation rulemaking, EPA considers new developments on the 

registration status and availability of alternatives that occur after the approval by Parties of a 

U.S. critical use exemption. For example, EPA made specific reductions in the amount of 

methyl bromide allocated in 2006, 2007, and 2008 to account for the registration of sulfuryl 

fluoride. Were California to register dimethyl disulfide or finalize provisions that facilitate 

the use of chloropicrin, EPA would evaluate the potential uptake of that alternative on critical 

use crops and potentially make reductions to the allocation as a result.