Filename USA CUE14 MBTOC REPLIES PART II 08-2012 Page 1

NOMINATING PARTY: The United States of America

DATE: AUGUST 20, 2012

FILE NAME: USA CUE14 MBTOC REPLIES PART II 08-2012

BRIEF DESCRIPTIVE TITLE:

Methyl Bromide Critical Use Nomination for 2014, U.S. Replies to MBTOC Report (Submitted 

in 2012 for 2014 Use Season)

CROP NAME (OPEN FIELD OR PROTECTED): Dried Fruit Products

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: Teung Chin, Ph.D. 

Title:

Address: U.S. Department of Agriculture

Office of Pest Management Policy

1400 Independence Ave., S.W.

Room 3871 (Mail Stop 0314)

Washington DC, 20250 U.S.A.

Telephone: (202) 222-8619

Fax:

E-mail: teung.chin@ars.usda.gov

Dried Fruit Products

MBTOC (TEAP 2012) recommends 0.487 tonnes for use in dried fruit and walnuts in 2014, 

a 34% decrease of the Party’s nominated amount. The recommendation is disaggregated into 

the following amounts: California walnuts 0.161 tonnes; dates 0.325 tonnes and dried plum 

board 0.001 tonne. 

U.S. Reply

As explained in more detail below, we believe additional time is necessary for the industry to 

transition to the most appropriate alternatives in this sector. The United States is therefore 
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requesting that MBTOC recommend 254 kg, the full amount nominated for dried fruit (dried 

plums, figs, and raisins) in the 2014 U.S. critical use nomination. The U.S. response to 

MBTOC’s suggested alternatives are discussed individually below. 

Alternative #1 – Phosphine

Because rapid throughput is needed, particularly during peak harvest periods to feed the processing lines, 

Sulfuryl Flouride (SF) or Methyl Bromide (MB) are the fumigants of choice due to their shorter 

fumigation times. The industry has already transitioned as much as it can to SF and phosphine. 

However, research by Walse et al. (2009) indicates that under low temperatures and current label rates, 

the efficacy of SF is inadequate against the eggs of the major stored product pests (dried fruit beetle, red 

flour beetle, and Indianmeal moth). Control of the egg stages of target pests is imperative. The USDA 

Agricultural Research Service is currently undertaking research to enhance the efficacy of SF on eggs 

using propylene oxide. The facilities that still require methyl bromide need more time for their transition 

as they are waiting for the outcome of this research, including a possible need for a regulatory review by 

EPA. A transition to SF, if egg control could be improved, rather than phosphine would allow the 

remaining facilities to avoid the need to purchase the chambers and other equipment retrofits needed for 

phosphine fumigation 

Alternative #2 Cold Storage Following Heat Drying to Prevent Reinfestation.

Total new cold storage construction costs for prunes, raisins and figs would be substantial, even assuming 

the producer would not have to incur costs in acquiring land for that purpose. Cold storage also involves

reoccurring costs related to consumption of electricity for cooling and maintenance in addition to those 

fixed construction costs. Because of the need for staff to continually enter and exit the storage area 

throughout the shift (with two to three shifts per day) to feed the processing line, stored product insects 

cannot be totally prevented were cold storage to be constructed. Furthermore, even with cold storage, 

methyl bromide is needed because of the ineffectiveness of SF at cooler temperatures. 

Alternative #3 - Propylene Oxide

The current propylene oxide (PPO) label limits the size of chambers to 10,000 cubic feet, a size 

impractical for the tons of dried fruit involved. In addition, there is a 200 foot buffer requirement for use 

of PPO in 10,000 cubic foot chambers, which would negatively impact ongoing plant operations. 

Furthermore, the label requirement1for 8% PPO includes a minimum heat treatment of 100 oF (37.8 oC), 

which would be costly. 

PPO is more effective on the egg stage of many insect pests of dried fruit than SF. As noted above, a

combination treatment of PPO and sulfuryl fluoride is being researched by the USDA Agricultural 

Research Service that could minimize disruption to the current dried fruit processing flow and retain 

current processing equipment without major modification. This effort is being undertaken to establish an 

effective treatment using SF and PPO against eggs at 20 oC and under, i.e., during the cooler season. 

Changes in use patterns such as a fumigation with a combination of SF plus PPO or the use of PPO in 

larger chambers could require regulatory review by the EPA to allow for label revisions. 

 

1

http://www.epa.gov/pesticides/chem_search/ppls/047870-00003-20100519.pdf
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Alternative #4 Sulfuryl Fluoride (SF)

Sulfuryl fluoride (SF) is currently used on dried fruits and is effective during the warmer months. 

However, at the current label rate, SF exerts inadequate control at cooler temperatures (20 o C and under) 

during the cooler months against stored product pests such as the dried fruit beetle. This is confirmed in 

the Technology and Economic Assessment Panel’s 2011 Progress report, which notes that “the target 

dosage rate of SF, typically a ct-product of 1500 g h m-3 over 24h at 26 °C, is insufficient to fully control 

eggs of some common species of stored product insect pests” and that the “temperature range of the 

current Fumiguide is limited to temperatures above 20°C and below 40°C.” (United Nations 

Environment Programme (2011). Special review on achieving control of pest eggs by sulfuryl fluoride. 

In Report of the Technology and Economic Assessment Panel. Pages 109 and 112. 

http://ozone.unep.org/Assessment_Panels/TEAP/Reports/TEAP_Reports/TEAP_Progress_Report_May_2

011.pdf ) Research is ongoing on how to apply lethal dosages to the insect eggs at lower temperatures. 

The costs of raising the temperature in the storage warehouses to allow for more effective treatment of 

dried fruit with SF under the current conditions would be expensive and additional time would be 

required to gain experience with their use and to resolve logistical issues. 

Alternative #5 Carbon Dioxide Under Pressure 

The dried fruit industry has previously evaluated the use of controlled atmosphere (CA) storage. While an 

efficacious treatment, the additional costs render it not economically viable. According to Dr. James 

Thompson, Agricultural Engineering, UC Davis, construction costs for CA are 10% more than 

conventional Normal Atmospheric Pressure (NAP) storage. Newer storage chambers could be retrofitted

at the additional costs but most of the industry’s chambers are too old to be retrofitted. 

Alternative #6 Aerosol Applications in Sites Where Products Are Processed, Bagged, and Stored. 

The dried fruit industry has been using aerosol applications to control insects for several years. 

Consequently, the numbers of fumigations required have been reduced as a result of aerosol use in 

conjunction with pheromones and sanitation. For example, dried plums now typically require only one 

fumigation per year instead for three. Aerosol applications are effective to keep flying adult populations 

down but are unable to penetrate into the centers of bins, which is problematic. Aerosol applications of 

pyrethroids are applied when flying insects are detected, typically using pheromone traps. A mating 

disruption pheromone for Indian Meal moth is also used but there is none currently registered for dried 

fruit beetle or red flour beetle. In addition, producers follow good hygiene practices to reduce the risk of 

infestation. (For example, it is common practice to clean floors at least once a week with commercial 

floor cleaners.)

Summary of Research Projects and Results

Johnston, J.A.; Walse, S.S; Gerik, J.S. 2012. Status of Alternatives for Methyl Bromide in the United 

States. Outlooks on Pest Management. 2012, 23(2), 53-56. 

Walse, S.S.; Tebbets, S.; Leesch, J.G. Multifactorial exploration of the insecticidal efficacy and 

degradation of sulfuryl fluoride in stored walnuts. Journal of Stored Product Research (in press) 

BRIEF

The navel orangeworm (NOW), Amyelois transitella, is a pest of concern to countries that import 

inshell walnuts from California. The individual and interactive effect(s) of pressure, temperature, 

time, and sulfuryl fluoride (SF) dose on NOW egg mortality and residue off-gassing from stored 
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walnuts are quantitatively delineated; a multifactorial experiment was generated and the results 

were analyzed using Design Expert 7.0 (Stat-Ease, Inc.). The mathematical models generated in 

this study can be used as predictive tool for ensuring that targeted mortality and minimum 

residues levels are achieved during individual fumigation events. This should be particularly 

useful to industry when “quarantine” control of insects (i.e., 99.9986% mortality) and MRL 

verification is required to move commodity through foreign trade and marketing channels.

Walse, S.S.; Tebbets, S.; Leesch, J.G. 2012. Ovicidal efficacy of sulfuryl fluoride to insect pests of 

California dried fruit and nuts. California Agriculture (in press) 

BRIEF

Amyelois transitells (navel orangeworm), plodia interpunctella (Hübner)(indianmeal moth), 

Tribolium confusum (red flour beetle), and Carpophilus hemipterus (dried fruit beetle) were 

fumigated at 60 F for 24 h under normal atmospheric pressures as well as for 4 hours at a reduced 

pressure of 100 mmHg. Dose-mortality responses for each species under both scenarios are 

presented and discussed in the context of the technical efficacy of sulfuryl fluoride as a 

postharvest methyl bromide alternative.

Walse, S.S; Hurley, M.; Wample, R.L.; Hartsell, P.; Pena, B.; Muhareb, J.; 2012. Efficacy of sulfuryl 

fluoride, propylene oxide and carbon dioxide fumigant mixture toward red flour beetle, T. castaneum. 

Journal of Stored Product Research (in press) 

BRIEF

A practical strategy is presented for overcoming the ovicidal deficiency of Sulfuryl Fluoride in 

stored product disinfestations. Sulfuryl Fluoride (SF), Propylene Oxide(PPO), and Carbon 

Dioxide(CO2) mixtures were used for the control of T. castaneum eggs and ovicidal activity was 

directly compared to fumigation with methyl bromide and sulfuryl fluoride alone.

Phillips, T., E. Thoms, J. DeMark, and S. Walse. 2012. Fumigation, Chapter 14. In Stored Product 

Protection. KState Research and Extension publication S156. (In press). 

Hall, W.; Walse, S.S.; (2011) The capture and destruction of methyl bromide vapors following 

postharvest fumigation, Proceedings of Methyl Bromide Alternatives and Emissions. Summary 

available at: http://mbao.org/2011/Proceedings/55HallW.pdf