1 METHYL BROMIDE CRITICAL USES NATIONAL MANAGEMENT STRATEGY UPDATE SUBMISSION BY THE UNITED STATES OF AMERICA

OCTOBER 30, 2009
This document updates the National Management Strategy the US Government (USG) prepared in 2005 as called for in Decision XX/5

. It provides the most current information on Critical Use Exemption ( CUE ) sectors that have successfully transitioned from methyl bromide use to alternatives , and those that have reduced their use within the U nited S tates

. Additionally, it describes the ph ase

- in process once an alternative is determined feasible, with respect to research programs

. This document is not meant to replicate the detailed technical information in the Critical Use Nominati ons (CUN) submitted by the USG.


# Introduction

Methyl bromid e use for the CUE de clined significantly since 2005. C urrently , MBTOC recommendations for critical use nominations are at 8 % of the 1991 baseline , a 7 6% reduction as compared to 40% of the 1991 baseline in 2005 (see Figure 1)

. Th e U nited S tates continues striv ing toward developing technically and economically feasible alternatives for the remaining

uses.

Figure One: Methyl Bromide Nominations and Authorizations

The US E nvironmental P rotection A gency (EPA) has completed assess ments for four soil fumigant s : methyl bromide, dazomet, metam sodium/potassium, and a new active ingredient,2

iodomethane. EPA considered 1,3

- dichloropropene (1,3

- D) along with the other soil fumigants for comparative purposes. As a result
, EPA requir es a number of mitigation measur es such as buffer zones, buffer zone posting, respiratory protections, restrictions on the timing of tarp perforation and removal operations, entry restrictions, and f umigant management plans (FMPs). These mitigation measures affect the use of methyl bromi de as well as alternatives to methyl bromide and affect the continued transition efforts. All product labels will be amended to reflect the changes by 2011. 

# Successfully Transitioned Sectors

Some of the sectors previously nominated for CUEs have transit ioned from methyl bromide in the last few years. They are listed below:



### Post

- harvest uses The registration of sulfuryl fluoride led to the successful transition for post

- harvest uses for goods such as dry beans, her bs and spices, cocoa beans, dried milk
, a nd pistachios

. Effective 2010, b akeries will transition away from methyl bromide use. These bakeries a re operated by large food processing corporations. They have significantly reduced their fumigations by investing in additional personnel and building and equipment modifications (such as building sealing) to improve their integrated pest management (IPM) strategies. In addition to the improvements in their IPM strategies, they are using spot treatments, heat
, and sulfuryl fluoride to manage their pest pres sures. The applicant for cocoa bean fumigations, National Pest Management Association ( NPMA)
, funded a feasibility analysis which demonstrated that sulfuryl fluoride was cost

- effective for use. As a result, cocoa beans are no longer fumigated with methyl bro mide. Pistachios have also transitioned from methyl bromide to propylene oxide
, a very effective treatment for salmonella

. T his transition was prompted by concern over salmonella contamination, which cannot be treated with methyl bromide

. Large capital in vestments are necessary to enable facilities to transition from methyl bromide for post

- harvest commodities

. Since us ing heat requires changing sprinkler systems to avoid an inadvertent start below 145°F, some facilities must be designed specifically to al low heat
treatment

. T he corrosiveness of phosphine requires some facilities to have sealed metallic equipment with plastics to protect it during fumigations. Larger, more profitable companies increase staff to conduct labor

- intensive micro

- sanitation, whi ch includes thorough vacuuming, cleansing with cotton swabs, sanitation, and daily inspection

. 

### Pre

- plant uses The US has seen successful transitions in a number of pre

- plant uses

. G inger ha s transitioned to using 1, 3

- D (telone)

. T omat oes grown in the Eas tern U nited States have transitioned to using a combination of 1,3

- D + chloropicrin, followed by chloropicrin, then metam

- sodium or metam potassium (the G eorgia 3

- way ) and iodomethane

.3 

# Sectors Using Methyl Bromide

Commodities Methyl bromide CUE s for commo dities declined by 89% since 2005, with a dramatic 80% decline in the US nomination between 2009 and 2011

. Fumigations of stored commodities typically occur over a very short period, during the peak production season when the bulk of the harvest is moving into the storage and shipping channels. These periods can be compressed when harvest occurs close to key market windows, such as holiday markets for certain types of nuts.

Figure 2. Commodities reduction in CUEs (Note: 2011 amount represents recommenda tion by MBTOC prior to Parties’ authorization )

. Dry beans. Rapid fumigation at harvest time and during shipping continues to be the primary justification for the use of methyl bromide on dry beans to primarily target the indianmeal moth. It is used at a rate of 2.75 lb/1,000 cubic feet.

Dates. Methyl bromide control s the carob moth and other insects infesting dates. Sulfuryl fluoride is currently labeled for use on dried dates, but most dates grown in the California are harvested fresh.

Dried fruit. D uring harvest
, methyl bromide yields a quick turnaround time for dried fruit , at the rate of 1.5 lb/1,000 cubic feet. Phosphine gas and sulfuryl fluoride are used for stored dried fruit fumigation.

Walnuts. In walnuts
, codling moth eggs are somewhat more tolerant than larvae t o sulfuryl fluoride fumigation. Although they do not occur naturally on walnuts at the time of harvest , navel orangeworm is a pest of concern. The navel orangeworm
, primarily a scavenger, also infest s walnuts after hull split, espec ially in areas that support high orangeworm populations. Occasionally, larvae emerging from eggs laid directly on4

walnuts before harvest may penetrate and infest the nutmeat through cracks in the hull

. Sulfuryl fluoride is not effective on this pest when the treatment occurs under vacuum conditions.
While sulfuryl fluoride appears to have potential as a methyl bromide replacement, various economic and technical issues ( e.g., inadequate egg kill) remain unresolved. USDA/ARS is investigating its efficacy on dried fruit beetle, as well as i ndianmeal moth and red flour beetle, on dried fruit. Preliminary results have indicated that sulfuryl fluoride has not demonstrated the same efficacy that the registrant achieved, especially on the dried fruit beetle eggs. Dried fruit beetles must be controlled as they can be very damaging to dried fruit in storage. B ased on USDA/ARS research with navel orangeworm eggs on in

- shell walnuts
, the CT (concentration and time cross

- product) alone may not an accurate predictor o f mortality

. Sulfuryl fluoride is more sensitive to lower temperatures than m ethyl bromide, which results in the need for greater amounts of sulfuryl fluoride when temp erature drop s. Research with sulfuryl fluoride indicates promise as a potential methyl bromide alternative for commodities. These early studies have shown that, under vacuum or atmospheric conditions, sulfuryl fluoride is effective against adult, pupal, and larval stages of insects infesting walnuts, but less effective against the egg stage. USDA/ARS researchers ran comparative efficacy tests with sulfuryl fluoride and methyl bromide in 2008. Users are investigating the feasibility of using sequential or combined treatments with sulfuryl fluoride and propylene oxide (PPO) as a methyl bromide alternative for control of pests in stored products. This will determine if combinations of sulfuryl fluoride and PPO will be more efficacious and cost effective than methyl bromide, especially regarding the egg stage of several economically important in sects that infest tree nuts and dried fruit

. 

### Cucurbits Methyl bromide CUE s for cucurbits has declined by 82% from 2005 levels (see Figure 3)

. Growers have switched from a 98% methyl Bromide formulation to a 67 % formulation

. The United States nominated for CUEs only the cucurbits grown in areas where the alternatives are not efficacious or are under regulatory restrictions.
Alternatives may be comparable to methyl bromide as long as key pests occur at low pressure

. I n such cases
, the United States nominat es areas where the key pest pressure is moderate

- to

- high such as nutsedge in the Southeastern U nited S tates

. Regulatory restrictions due to karst geology in Georgia limit the use of Telone. Substantial losses in yield render 1,3

- D +chloropicrin and
metam

- sodium technically infeasible for control of nut

- sedge in cucurbits in Georgia and the Southeastern US. In Michigan, Maryland, and Delaware
, 1,3

- D + chloropicrin are technically feasible yet economically prohibitive for use in melon production. Additional ly, their use would significantly lower the price of the produce due to the changes in the harvest schedule caused by the longer plant

- back interval for telone+chloropicrin (two weeks longer than methyl bromide+chloropicrin). Additional delays would also o ccur in Michigan since the soil5

temperature must be higher to fumigate with alternatives. These soil temperature complications and extended plant back intervals when using 1,3

- D + chloropicrin result in users missing key market windows, and adversely affec t revenues through lower prices. The ability to sell produce at these higher prices makes a significant contribution toward the profitability of cucurbit operations

.

Figure 3. Cucurbits reduction in CUEs

.
U sers have been experimenting with significant in creases in the level of chloropicrin and reductions in the level of methyl bromide. While these new mixtures have generally been effective at controlling target pests at low to moderate levels of infestation, their long

- term efficacy is unknown. Tarpaulin (high density polyethylene) is also used to minimize use and emissions of methyl bromide. In addition, cultural practices are utilized by cucurbit growers.
Reduced methyl bromide concentrations in mixtures, cultural practices, and the extensive use of tarp aulins to cover land treated with methyl bromide have resulted in reduced emissions and an application rate that is among the lowest in the world for the uses described in this nomination. Research is underway to develop use of a 50% methyl bromide formula tion in Michigan commercial production systems. 

### Eggplants Methyl bromide CUEs for eggplants declined 7 2 % from 2005 (see Figure 4)

. In Florida, Georgia, and Michigan (primary eggplant

- producing states), adoption of alternatives is limited by regulatory co nstraints, high pest pressures, and longer planting and harvesting periods.6

Figure 4. Reduction in Eggplant CUEs

.

• In Florida and to a lesser extent in Georgia, use of 1,3

- D is prohibited in areas overlying karst topographical features because of ground water contamination concerns.

• In Florida and Georgia, where nutsedge is the main methyl bromide target pest, neither 1,3

- D nor metam sodium, alone or in combination with chloropicrin, adequately control moderate to high nutsedge populations. Additionally
, use of products containing 1,3

- D and metam sodium in the fall may be impractical because of the required longer waiting periods for planting following application (28 days for 1,3

- D and 21 days for metam sodium, compared to 14 days for methyl bromide).

• I n Michigan, where soil

- borne pathogens are the key methyl bromide target pests, neither 1,3

- D nor metam sodium is effective against soil

- borne fungi.

• In Michigan delays are associated with the need for higher soil temperature to fumigate with alternatives . Delays in planting and harvesting may result in narrower market windows and reduced farm revenues. Until 1999, the chemical formulation primarily used was 98 percent methyl bromide and two percent chloropicrin. Since then, growers have shifted to formula tions with lower concentrations of methyl bromide and higher amounts of chloropicrin due to the phase

- out schedule of methyl bromide.

• In Georgia, nearly all vegetable production occurs on Coastal Plain Soils, which are subject to high temperatures and exce ss heat. This section of Georgia suffers from weed pests as well as weed pests, soil

- borne fungal pathogens
, and plant

- parasitic nematodes
, and nearly all production areas have severe infestations, necessitating annual treatment with a soil fumigant.7



### Nu rsery Stock Fumigation is necessary to meet certification requirements (CDFA, 2003) for nursery stock. Use rates of methyl bromide have been reduced from previous years (see Figure 5) . Some nurseries have reduced the methyl bromide proportion in the formul ation with chloropicrin

.

Figure 5. Reduction in CUEs for Nursery Stock
Key alternatives in use include combinations of 1,3

- D, chloropicrin, metam

- sodium, and dazomet. These chemicals and other strategies, like low permeability tarps, have reduced the us e rate for methyl bromide. However, the need for methyl bromide still exists. Reasons for critical use of methyl bromide include:

1,3

- D is not an approved treatment for fine

- textured soils
G reater inputs are required for soil preparation and moisture mana gement
T ownship caps and buffer zone requirements

W eed management efficacy

A ir quality standards related to volatile organic compounds
The requested amount of methyl bromide in the U S nomination includes those areas where 1,3

- D would not meet the certifica tion requirements or would be limited by township caps. Iodomethane has been registered for use in 47 of the 50 states. I t is important to note that iodomethane , like methyl bromide, is a restricted use pesticide requiring pesticide applicator training, a s well as an applicator license . Once training has been provided, iodomethane application must be under the direct (observed) supervision of these trained personnel.

I odomethane is not registered in California. Under California regulatory laws, nursery cr ops must be “free of especially injurious pests and disease symptoms” in order to qualify for a CDFA Nursery Stock Certificate for Interstate and Intrastate Shipments (CDFA, 2003). Washington has8

similar regulations (WDA, 2007). If an approved fumigation i s not used in the nursery, CDFA imposes a nematode sampling procedure ; if nematodes are found
, all nursery stock in an area are destroyed resulting in a complete loss. If nematodes are found and the nursery stock is not “free of especially injurious pests and disease symptoms
, ” then a total loss is likely because the nursery stock: 1) would not qualify for a CDFA Nursery Stock Certificate for Interstate and Intrastate Shipments, 2) would likely not be marketable since resale for planting is severely restric ted by the CDFA, and 3) should be destroyed to prevent further infestation. Some nurseries have reduced the methyl bromide proportion in the formulation with chloropicrin. In addition, where soil conditions and regulations allow, 1, 3

- D may be used as an a lternative to methyl bromide, but it appears to have a relatively limited use due to regulatory restrictions and soil moisture requirements. Remaining u ses include: raspberry nurseries, deciduous tree nurseries, and rose stock.
Raspberry nurseries in the western United States provide raspberry stock to most of the growers in North America. Dry climates and soils make these areas ideal for production of high quality plant stock. Although there are relatively few raspberry nurseries, they provide all of th e stock used by commercial growers, and therefore, have an impact on raspberry production overall.

For n ursery production the industry must meet a 99.9% control and provide stock for orchards that is pest

- free (particularly nematode

- free)

. In California deciduous tree nurseries, approximately 30% have silt or clay loam soils requiring methyl bromide. The remaining 70% have sand or sandy loam soils. Approximately one half of these areas have a critical need for methyl bromide due to moisture requirements. According to the applicant, 65% of nursery soils in California have a critical need for methyl bromide. Township caps for 1,3

- D may further limit the use of the best alternative.
Research trials in strawberry nurseries (a model for raspberries) indicated t hat methyl iodide with chloropicrin, chloropicrin followed by dazomet, and 1,3

- D with chloropicrin followed by dazomet are potentially effective alternatives to methyl bromide. Transitioning to these potential alternatives will require addressing regulato ry issues (e.g., methyl iodide is not registered for use in California, chloropicrin at high rates is restricted in California, township caps restrict the use of 1,3

- D in some areas of California) and certification requirements.
Advances are being made in technology for low permeable and colored films. Broadcast application continues to experience difficulty in gluing high barrier films ; although
, progress is apparently being made. Protocols of the already identified alternatives (1,3

- D, chloropicrin, dazo met, and metam

- sodium) are being developed primarily to identify the most effective combination or sequence of applications (e.g., chloropicrin followed by dazomet). Because of certification requirements, however, standards of efficacy are stricter than fo r other commodities.
Raspberry nurseries have spent $100,000 on research, including $20,000 on screening resistance for Phytophthora and Verticillium, and over $60,000 over the last decade studying various9

alternatives in the large Watsonville, California area. There are regulatory limitations to the use of 1,3

- D, yet growers must meet certification requirements. In addition, 1,3

- D does not control Verticillium dahilae, Pythium spp., which are pests of raspberry and roses nurseries. Studies are also ongoing to discover how application methods can improve efficacy of chemical alternatives such as 1,3

- D and metam

- sodium, and mixes of chemicals. Moisture constraints, both too much and too little, can reduce efficacy of effective chemicals such as 1,3

- D, especia lly when soil textures are not optimal for their physical chemistry.



### Food Facilities

Since 2005 , the CUEs for rice mill s ha ve been reduced by 90%, pet food facilities by 75%, and flour mills by about 60% . Th ese result in a 75% overall sector reduction in t he requested methyl bromide use. Food processing facilities in the United States have reduced the number of methyl bromide fumigations by incorporating a variety of different techniques to control pests. The most critical strategy implemented is IPM, espec ially sanitation, and equipment design modifications to enable cleaning and inspection in all areas of a facility. Facilities are now being monitored for pest populations, using visual inspections, pheromone traps, light traps
, and electrocution traps. Whe n insect pests are found, facilities will attempt to contain the infestation with treatments of low volatility pesticides applied to surfaces as well as cracks and crevices; spot treatments with heat or phosphine are also used where suitable. Incoming ingr edients are inspected for insect pests and may be treated with phosphine if temperature and time are sufficient ; otherwise contaminated ingredients may be rejected. These techniques do not disinfest a facility but are critical in monitoring and managing pe sts, and hopefully preventing outbreaks. However, when all these methods fail to control a pest problem, facilities must rely on fumigation, to kill insects within the processing equipment, bins, storage spaces and even within the walls of the structure. M ethyl bromide and sulfuryl fluoride are the two primary fumigants used in food facilities

.

Figure 6. Reduction
, food facilit y CUEs

.10

Although sulfuryl fluoride has helped in the reduction in methyl bromide use in food processing facilities, the label does not include all foods that are in these facilities. Because pet food, pasta, potato chips
, and cake mixes are not listed on the product label , for example, facilities storing any of these commodities may not fumigate with sulfuryl fluoride. For rice and f lour mills, and pet food manufacturing facilities with electronic components and with machinery with copper and copper alloy parts, methyl bromide is the sole fumigant available. These facilities are under intense pressure from many insect pests. The flour millers do not directly target their commodities with fumigation, although some may be present in the equipment or in storage areas. However, rice millers and pet food manufacturers may target some of their products during fumigations with methyl bromide.
Methyl bromide is used in facilities, or portions of facilities, that are unsuitable for the alternatives, and where the alternatives are not economically feasible. Because the efficacy of sulfuryl fluoride is highly dependent upon temperature, its use ma y not be cost

- effective during cold temperatures . Also sulfuryl fluoride requires higher dosages for egg kill, but in some facilities killing eggs is paramount, again contributing to higher costs. Phosphine is corrosive to many metals that are present in f acilities, especially in the computers and other electronic process control instrumentation; and it is flammable. Heat is dependent on several parameters: the structural composition, as different components expand and contract at different rates; the build ing design/layout factors, which affect the ability to evenly distribute heated air; and the availability of convenient and economical sources of heat. In addition, heat may not be a viable option for treatment of food products or commodities.



### Forest Seedl ings Methyl bromide CUEs for forest seedlings has declined by 45% from 2005 levels (see Figure 7)

. Forest seedling nurseries in the U nited States supply conifer and hardwood seedlings that are used for reforestation, forest establishment, fiber production, Christmas tree production, wildlife and conservation. Nurseries must ensure that they produce high quality, disease

- free tree stock. Depending on regional regulations government certification requirements may vary
, but nearly all jurisdictions have regula tions in place to ensure quality stock plants. Most nurseries implement a zero

- tolerance criterion for pathogens and nematodes and apply quality control and grading requirements in order to minimize the possibility of spreading nematodes and diseases from state to state or throughout a state.
The Forest Seedlings sector has reduced its methyl bromide consumption through several techniques developed over the past several years. The sector has incorporated the use of high density polyethylene (HDPE) tarp mat erial that has helped increase fumigation efficiencies and reduced application rates. HDPE increases methyl bromide soil residence time, increasing efficiency and reducing application rates. Methyl bromide fumigation in the forest seedlings sector increasi ngly has been made using deep injection that places the material deeper into the soil , contributing to longer residence time and greater application efficiency. This has been11

accomplished at considerable capital investment on the part of applicators

. Fores t seedling nurseries have increased the percentage of chloropicrin in fumigation mixtures. While 98% methyl bromide and 2% chloropicrin was the most widely used compound a few years ago, a 66:33 formulation is now more common, especially in areas without h eavy nutsedge infestations.

Figure 7. Reduction in methyl bromide CUE for forest seedlings

. Methyl bromide has been a critical treatment because of its contribution in enabling nurseries to meet state regulatory standards of pest

- free status. The use pr otocols for the available alternatives have not been developed sufficiently to provide effective control of the key pests to depths of 1m. T here are few, if any, markets for plants that do not meet the certification standards, meaning that losses up to 100 % are possible when inadequate pest control occurs. Failure to adequately manage pests in transplants will jeopardize the viability of the planted forests. This sector is covered by certification standards as plant material is transported and transferred t o various locations throughout the U nited S tates

. All states have certification standards and all nurseries have additional internal quality control standards as well. USDA

- APHIS has guidelines for the movement of nursery material to contain diseases ( i.e
., sudden oak death). The key alternatives are 1,3

- dichloropropene (1,3

- D)/chloropicrin, 1,3

- D/chloropicrin/metam

- sodium, 1,3

- D/metam

- sodium, dazomet ( as a follow

up application to 1,3

- D/chloropicrin or chloropicrin ) , and iodomethane. Few growers have expe rience using iodomethane. They are developing the experience selecting a dose and determining which cultural practices are necessary to obtain the best results for the iodomethane application.
Methyl bromide is particularly effective where moderate or high nutsedge populations are endemic. The forest tree nursery industry in the U nited S tates is diverse in tree species that are grown and large in overall scale. Nurseries produce seedlings adapted to their respective regional areas, taking into account such variables as climate, elevation, and soil type. Nutsedge species12

are generally considered among the major pests of forest seedling nurseries, especially in S outheast ern U nited S tates

. Fumigation is relied on to manage pests that interfere with the growth of healthy seedlings. Chloropicrin is an effective fungicide, and is being examined as an overall fumigant when used alone, but weed management issues have to be addressed. Additionally, California has local restrictions on such high rates of chloropicrin. For areas where pest pressure is moderate or high, methyl bromide provides sufficient protection for three successive seedling crops, with one fumigation treatment (one treatment every four years).
Until protocols are developed to improve efficacy of alt ernative treatments, there may be a need to provide additional fumigation treatments, or use a combination of chemicals and other effective treatments that may increase costs, beyond what is feasible. Dazomet and metam

sodium are not reliable in cooler cli mates ( e.g., Michigan). Metam

- sodium does not consistently dissipate in heavy soils due to low vapor pressure. For high i mpact sites, dazomet and metam

sodium show inconsistent results with weeds, especially with moderate

- to

- high weed pressure. They do not consistently provide acceptable levels of nutsedge control, nor does it manage some diseases associated with fungal pathogens ( e.g., root rot and damping

- off pathogens).
Container production has been cited as a way to reduce methyl bromide in this sector

. It is used for seedling production in a limited capacity throughout the forest nursery sector. Less than 10% of the national forest seedling production is containerized. Container production is used for specialty purposes, for example, to reforest mine

- s poil sites which are extremely harsh edaphic environments requiring a soil plug system to obtain adequate seedling survival. A large investment would be necessary to shift the national production to containers, as well as a shift for many nurseries in the well

- established protocols of growing seedlings. According to the US Forest Service, 48% of all reforestation in the U nited S tates is done on non

- industrial private lands, 42% on industrial lands, and 10% on government lands. The result of container produc tion would be a significant increase in reforestation costs and a decrease in the rate of reforestation.
Research is ongoing to develop commercially feasible protocols for likely alternatives like 1,3

- D and metam

- sodium, low permeability films, and integra ted methods with chemicals and non

chemicals. A recent study found that virtually impermeable film (VIF) with methyl bromide used at 168 kg/hectare provided comparable results to methyl bromide used at 392 kg/hectare with high density film. Technical probl ems still exist when gluing VIF during broadcast applications, which is the standard application method for the industry. Technical, economic, and regulatory consideration s affect that transition times for alternatives. Combinations of chemicals such as ch loropicrin, metam

- sodium, or 1,3

- D appear to be effective for some nurseries in reducing pest infestations, including some weed problems. Combinations of these compounds and application techniques (such as deep injection) to achieve the same pest control e fficiencies as methyl bromide are being studied along with non

- chemical treatments, such as bed

- fallow or cover crops.13

In research plots, the reduction of methyl bromide from 98:2 to 65:35 or 50:50, increased periods of cover crop growth, use of herbicides , and an increased use of mechanical cultivation might reduce pest populations, and the overall use of methyl bromide. However, nursery managers are unlikely to adopt the use of glyphosate immediately since it kills both hardwoods and conifers. Experiments have indicated that some soil amendments can reduce possible adverse growth effects of some alternatives (e.g., dazomet). Work in Wisconsin suggested that white pine seedlings subjected to dazomet, but supplied with various nutrients, could reduce chloros is sometimes observed in dazomet treated beds. Large scale trials will be necessary to confirm this effect. For disease control, studies comparing cultivation practices, such as till vs. no

- till and organic amendments indicate that effects vary according t o the species grown

. Therefore, each nursery may have to consider alternatives with species and local environment in mind, unlike the more consistent effects of methyl bromide fumigation. Promising results in disease management have been observed with orga nic amendments, but successful weed management has not been adequately achieved.



### Ham Methyl bromide CUEs have been reduced by 97% since 2005 (see Figure 8)

. Currently there are no alternatives to methyl bromide for this industry. P hosphine does not control mites (a major pest)
, and heat would alter the product.

Figure 8. Reduction in CUEs for ham.

Producers of cured pork products experience pest pressure from insects such as the ham skipper, the red legged ham beetle, dermestid beetles, and mites. These pests infest and feed on meat, especially deep inside the meat along the bone, as it cures and ages. Environmental conditions (temperature and humidity) in and around the facility strongly influence the level of pest pressure. Under favorable ambient cond itions, such as those seen in silo curing, pest pressure14

increases and a regular fumigation sc hedule is recommended. In the US , the Food and Drug Administration (FDA) regulates the maximum levels of live or dead insects or insect parts that may be present in stored food products. Food commodities that exceed maximum limits allowed are considered adulterated by FDA and thus
, unfit for human consumption.
This industry is cooperating with university researchers to find technically and economically feasible al ternatives to methyl bromide. In the meantime, several companies have modified their buildings to make them more gas

- tight. Some companies are eliminating grass, trees, and shrubs from their properties and replacing it with gravel, as suggested by research ers last year. 

### Orchard Replant Methyl bromide CUEs in the orchar d replant sector have been reduced by 71 % from 2005 (see Figure 9) . Transition to alternatives has allowed an additional reduction in hectares requiring methyl bromide. The almond replant sub

- sector has significantly reduced fumigant applications for replant by treating individual tree

- planting holes or reduced strip area rather than broadcast or standard strip treatments.

Figure 9. Reduction in CUEs for orchard replant

. The Orchard Replan t sector comprises stone fruit, almond, and walnut orchards, and grape vineyards grown throughout California. Growers of these crops face the common threat s of nematodes and a poorly understood disease complex called O rchard R eplant “ P roblem” or

“ D isorder” . Methyl bromide is used in areas where alternatives are not suitable, either because of legal restrictions or physical features, such as unacceptable soil type or moisture. Since orchard fumigation occurs only once during the bearing life of the trees, th e most efficient system to produce the healthiest trees is necessary to avoid early tree removal, added costs, and lost revenue due to necessity of planting and then replanting orchards if replant disorder is not initially addressed. Typically fruit orchar ds and vineyards can produce for 20

- 25 years, walnut orchards can produce for 40 years, and almond orchards produce on average 25

- 30 years.15

The best alternatives identified for orchard replant are 1,3

- D or 1,3

- D with chloropicrin, and/or
metam

- sodium, esp ecially in coarse textured soils. Under some soil and moisture conditions (less than 12% to 1.5 meters) 1,3

- D can be an effective management tool for replant problems. However , restrictions on its use and application
, including township caps and rate reduc tions in California , limit its use. There is a critical need for methyl bromide in some orchards in California, either because of legally mandated township caps for 1,3

- D, or because surface moisture requirements cannot be met (e.g., soils cannot be adequa tely dried prior to use of 1,3

- D). Iodomethane is not registered in California.
Research studies continue to explain the causes for replant disorder affecting the orchard replant
sector

. Research is also underway into identification of non

- fumigation met hods to kill remnant roots of outgoing orchard trees, which provide nutrients for soil

- borne pests that may infest new tree plantings.



### Ornamentals Methyl bromide CUEs in the ornamentals sector ha s decreased by 67% from 2005 levels (see Figure 10) . For th e remaining areas, t ransition is expected to be slow due to the complexity of the industry ; there are numerous crop species and varieties, and new varieties constantly being developed. Iodomethane is also registered for use in F lorida ( one of the states th at use methyl bromide for this sector ) . However, since few growers have experience using iodomethane
, selecting a dose and determining which cultural practices to use are necessary to obtain the best results.
Methyl bromide is used to control plant pathog ens, nematodes, and weeds, including nutsedge and volunteer crops. These pests not only cause yield losses, but also impact quality, which is very important for this industry and can result in economic infeasibility. The use of methyl bromide is very impor tant to the economic viability of this industry, particularly considering the cost and availability of labor

. In California, the nomination includes cut flowers, cut foliage, and perennials. Production occurs in open fields, tunnels, open

- ended and closed hoop

- houses, shade houses, and permanent greenhouses. U se restrictions on chloropicrin, township caps and lowered application rates in California , do not provide sufficient control of weeds. Furthermore, Iodomethane is not registered in California

.16

Fig ure 10

. Reduction in CUEs for ornamentals

. In Florida, some of the typical cut flowers grown are snapdragons, lilies, gladiolus, lisianthus, delphinium, and sunflowers. Both in Florida and California, growers often introduce new varieties which increases t he uncertainty in the susceptibility of the plant to pests or to residual pesticide applications. In Florida, the only efficient way to fumigate post rows is to use the hot gas method which can only be done with a 98:2 formulation. Formulations with a high er concentration of chloropicrin do not have this application method on the label and the chloropicrin content makes it impossible to heat it enough to get it to vaporize.
In Michigan, perennial herbaceous nurseries, grown in open fields, have been request ing methyl bromide to control nematodes and weeds. Some of the species grown are Delphinium, Hosta, and Phlox. There is a standard for herbaceous perennials in Michigan. In Michigan, growers cannot ship product without a clean inspection and a Michigan D epartment of Agriculture certification. Although fumigating is not a regulatory requirement, nor is fumigating with methyl bromide mandatory, crops need to grow free from nematodes and certain diseases in order to meet trade requirements.

T he plant

- back in terval for 1,3

- D+chloropicrin is two weeks longer than methyl bromide+chloropicrin, and in the N orthern U nited S tates an additional delay would occur because soil temperature must be higher to fumigate with alternatives. Delays in planting and harvesting r esult in users missing key market windows, and adversely affect revenues through lower prices. Growers have experienced damage to adjacent flower crops due to off gassing of chloropicrin when using formulations with higher chloropicrin concentrations than 98:2, such as 67:33. However, it is not known what would happen with regards to phytotoxicity in this situation with iodomethane: chloropicrin 50:50. Cool
, damp weather associated with this practice has the potential to be devastating. In addition, it has also been observed that growers experience lower yields with methyl bromide: chloropicrin 67:33 compared to 98:2.17

A major concern is potential phytotoxicity. In the ornamental industry, there is a large number and diversity of crops, plus a continuous bre eding program, and there is concern about crop damage (phytotoxicity) with use of iodomethane . Growers need to develop a level of confidence in its safety. Buffer zones may also be an issue.

Use of many fumigants without herbicides is likely not to suffici ently control weeds. However, contact herbicides to control post

- planting weeds may cause unacceptable damage the crop in the field, resulting in yield or quality losses. Solarization seems promising in Florida production but would take awhile to adopt. It takes several weeks to control many pests to a depth of 30cm. This length of time for a treatment is not economically feasible for many growers due to the intensive, year

- round production situation of the cut flower industry. S olarization is not feasib le under Michigan field conditions because of several factors, including the inability to generate adequate heat to allow spring planting and because the most effective time for solarization is not compatible with timing for production. Production areas in California are in mainly coastal regions where solarization is not feasible due to cool temperatures and cloud cover most of the year. Current research trials are aimed at alternatives. Chloropicrin, metam

- sodium and the other alternatives are being resea rched as both drip applied as well as broadcast applications. Research is being conducted on 1,3

- D/chloropicrin followed by an application of metam sodium one week later

. 

### Peppers Methyl b romide CUEs for peppers has decreased by 81% from 2005 levels (see Fi gure 11) . Use in the southern U nited States ha s transitioned to the three way combination of 1,3

- D followed by chloropicrin followed by metam

- sodium under VIF or metalized films, replacing spring

- time applications of methyl bromide+chloropicrin in areas wi thout 1,3

- D prohibition due to karst topographical features.

In the Southeastern U nited S tates , including Florida and Georgia, the three way combination of alternatives on spring plantings and iodomethane are considered technically (and thus economically) feasible alternatives to methyl bromide, although some limitations exist, such as regulatory restrictions. In those portions of the sector where alternatives are available, the U nited States is in the midst of a transition

. Methyl bromide remains in use for peppers grown in S outheastern U nited S tates , Florida (areas with karst topography), and Michigan. These crops generally are grown in open fields on plastic tarps, often followed by various other crops. Harvest is destined for the fresh market. 1, 3

- D u se is limited in Georgia and Florida due to the presence of karst topography. Michigan is cold and wet during the early spring thaw, and fall applications of alternative fumigants cannot be conducted. This potential for plant injury may require a longer of f

- gassing period, which may be needed to avoid phytotoxicity when using chloropicrin under VIF in cold climates. In pepper18

production additional delay in planting may result in producers missing the early, premium market. The cost of iodomethane may be pro hibitive compared to methyl bromide.

Figure 11. Reduction in CUEs for peppers

. Michigan CUE pepper farmers must plant by the first week of May to capture an early market window. This market window provides a premium crop price that remains critical for g rowers’ economic feasibility. Soil fumigation must
, therefore
, be completed by mid April to allow 14

- 21 days for aeration. However, 1
, 3

- D and metam labels recommend that applications be made when soil temperatures (at application depth) are above 4.4°C. Fu rthermore, optimum soil temperatures for 1,3

- D are in the 10°C

- 25°C range. Since soil temperatures in Michigan do not climb over 10°C until after mid to late May
, neither 1,3

- D nor metam products can be used effectively for early pepper planting in Michi gan. Metam products have the additional disadvantage that when the soil is wet and cold (below 15°C), the minimum recommended plant back period is 30 days, which would push the crop beyond the early market window.

In Southeastern United States , including F lorida and Georgia, methyl bromide is requested primarily for control of moderate to severe infestations of nutsedge weeds. M etam

- sodium offers inconsistent control of nutsedges and nematodes, while 1,3

- D + chloropicrin provides adequate control of nematod es and disease. M etam

- sodium has yield losses of up to 44 % compared to methyl bromide where weed infestations are moderate to severe . Metam

- sodium also creates a planting delay as long as 30 days to avoid risk of phytotoxic injury to crops compared to a 1 4

- day delay for methyl bromide. Furthermore, due to regulatory restrictions resulting from groundwater contamination concerns, 1,3

- D + chloropicrin cannot be used in large portions of S outheastern U nited S tates due to the presence of karst topographic feat ures, and anywhere in Dade County, Florida, where the majority of that region’s peppers are grown. There is also a 28 day planting delay due to regulatory restrictions for 1,3

- D + chloropicrin. In Florida particularly, growers are on a tight production sch edule and must place pepper transplants in fields at a certain time of the year. Relying only on metam sodium for pre

- plant treatment would force growers to19

fumigate earlier in their season, which would extend the fumigation schedule into rainy periods. Gr owers would have to fumigate earlier to avoid rain and lose a portion of the ir crop.

O nly methyl bromide can effectively control pepper target pests found in S outheastern U nited S tates , where pest pressures exist at moderate

- to

- severe levels. Most, if not all of these states, are limited in the use of the alternative 1,3

- D because of underlying karst topography throughout the region. Halosulfuron, while effective against nutsedge, is only registered for use on row middles in peppers. Metam

- sodium has limit ed pest control capabilities and sho uld never be used as a stand

- alone 

### Post Harvest ( National Pest Management Association

- NPMA) Methyl bromide CUEs in this sector has declined by 88% from 2005 (see Figure 12)

. Food processing facilities in the U nited S t ates have reduced the number of methyl bromide fumigations by incorporating many different techniques to control pests. The most critical strategy implemented is IPM, especially sanitation, in all areas of a facility. Facilities are now being monitored f

or pest populations, using visual inspections, pheromone traps, light traps and electrocution traps. When insect pests are found, facilities will attempt to contain the infestation with treatments of low volatility pesticides applied to both surfaces and cracks and crevices . S pot treatments with heat or phosphine will be used in areas that are suitable. Incoming ingredients are inspected for insect pests and may be treated with phosphine. These techniques do not disinfest a facility but are critical in m onitoring and managing pests, and hopefully preventing outbreaks.

Figure 1 2. Reduction in CUEs for NPMA

. Methyl bromide is used in treatment of processed foods ( e.g., chips, crackers, cookies and pasta), spices and herbs, and cheese processing plants. Me thyl bromide is typically utilized in processed food and feed facilities as a space fumigant for treating the facility 1 to 3 times per year. As the need arises, methyl bromide is also used for trailer fumigations of product or packaging material.20

These fa cilities are under intense pressure from many insect pests as well as rodents. Sulfuryl fluoride is highly dependent upon temperature, so should a facility need fumigation during cooler temperatures, it may not be the product of choice because of increased costs. Also
, sulfuryl fluoride requires higher dosages for egg kill

. I n many facilities
, killing eggs is paramount; this also may lead to higher costs. Phosphine is corrosive to many metals that are present in facilities, especially in the computers
, and is flammable. Heat is dependent on the structural composition, as different components expand and contract at different rates. Cheese does not have a technically and economically feasible alternative to methyl bromide at this time.
Methyl bromide fumigatio n for cheese occurs to ensure pest

- free food and meet the strict requirements of the Food Sanitation Regulations. Cheese manufacturers may target their products during fumigations with methyl bromide when a mite infestation is iden tified by USDA inspection and fumigation is ordered. Cheese does not have a technically and economically feasible alternative available. Whereas sulfuryl fluoride and phosphine are the primary alternatives in most commodities, they are unsuitable for cheese facilities. Phosphine f umigations take much longer than methyl bromide fumigations and are not a feasible alternative when rapid fumigations are needed; is corrosive to certain metals; is limited by temperature, and is not effective on mites. Sulfuryl fluoride is under investiga tion to determine its efficacy on mites, especially in the low temperature environment of cheese facilities.

T his sector is treating only the portions of the facilities that contain electronic components and have machinery with copper and copper alloy part s. These facilities are under intense pressure from many insect pests. The majority of these food processors do not target any of their commodities to be fumigated with methyl bromide, although some ingredients may be present in the equipment during fumiga tion, or the ingredients and products may be separable from the processing portion of the facilities. Methyl bromide is requested for a few small mills where herbs and spices are blended into packages (such as for pizza mixes) that are then added to pre

pa ckaged goods. These facilities are similar to food processing facilities in that there are silos, mixing areas, packaging areas, etc. The y utilize methyl bromide to target pests present in inaccessible areas of the structure, such as the equipment and buil dings. The ingredients or finished products that may be stored on

- site are not targeted for fumigation. However, the problem in some of these small mills is that they are all under one roof without any way to completely segregate the different areas. In ad dition, since these are small companies they have economic constraints. Fumigants of choice for treating herb and spice commodities are ETO, PPO, irradiation
, and phosphine. These alternatives are not feasible to disinfect the facility itself. 

### Strawberry F ruit Methyl bromide CUEs has declined by 53% from 2005 in this sector (see Figure 13)

. Strawberry growers have been replacing methyl bromide or reducing its use rates in all production areas. Over 50% of California strawberries are now produced without the use of methyl bromide and21

that percent likely will increase yearly. The lowest formulation of methyl bromide that is likely to be allowed in California is 57:43 (methyl bromide:chloropicrin).
Florida growers have transitioned to chloropicrin in fields wi th key disease problems even though those with sting nematode problems still require methyl bromide. Results of several years of research trials in Florida with high barrier films led to increase in the use of VIF

- type films which allows a significant redu ction in the methyl bromide application rates (25

- 50%), while maintaining efficacy. Iodomethane has recently been registered in all of the strawberry production states, except California. Its use will likely replace a significant portion of the critical

us e area for methyl bromide. T his tr ansition from methyl bromide to iodomethane is expected to increase as protocols for effective use of iodomethane are developed. Growers continue to reduce their reliance on methyl bromide and reduce the portion of the ind ustry that has a critical need for methyl bromide.

Figure 1 3. Reduction in CUEs for strawberry fruit

. California growers have a critical need for methyl bromide to treat fields where alternatives are not available due to regulations or to complete a fum igation program that includes a once per three year treatment with methyl bromide to manage two new diseases ( Macrophomina and Fusarium oxysporum )

. Additionally, i odomethane is unlikely to be registered for use in California in the near future

. Although u se of methyl bromide has been greatly reduced since 2005, this trend is in danger of being slowed if the incidences of two new diseases continue to increase in strawberry fields. High rates of chloropicrin (greater than 225 kg/ha) are restricted by regulat ion and lower rates may not be optimally effective against plant pathogens. Township caps restricting the use of 1,3

- D may affect between 5,700 and 9,000 hectares by 2011.
In Florida sting nematode problems require the use of either methyl bromide or 1,3

- D. However, strawberry fields are located above karst geological formations with restrictions on the use of 1,3

- D to prevent contamination of ground water. In the S outheastern U nited S tates , many of the farms contend with yellow and purple nutsedges, which are significant problems in some areas22

more than others. Farmers with a low incidence of nutsedge use other chemicals, such as chloropicrin, 1,3

- D, and metam

- sodium to manage diseases such as black root rot, nematodes, and other weeds. Iodomethane has rec ently been registered in all of the strawberry production states, except California. 

### Strawberry Nursery Methyl bromide CUEs for strawberry nurseries has been reduced by 87% from 2005 (see Figure 14)

. Nurseries currently use methyl bromide on all of their land for transplants designated as quarantine pre

- shipment (QPS), which makes up 99% of methyl bromide use by nurseries. The certification requirements for strawberry nurseries located in the states requesting critical use exemptions for methyl bromide ar e strict (zero tolerance for any damaging diseases and plant

parasitic nematodes) in order to minimize the prospect of spreading these pests to other states and countries where these plants are shipped.

Figure 1 4. Reduction in CUEs for strawberry nurser ies

. There are no markets for plants that do not meet the certification standards, which mean that losses up to 100% are possible when inadequate pest control occurs. Failure to adequately manage pests in transplants will jeopardize the certification proce ss and adversely affect fruit production industries in the U nited S tates , as well as the in countries purchasing US plants (e.g., Canada, Mexico, Spain, countries in South America, and others).
Transplants produced in California are distributed widely thro ughout the U nited S tates and other countries

. Currently , only methyl bromide and 1,3

- D are accepted treatments for nursery stock certification. Regulatory restrictions in California on the use of 1,3

- D and chloropicrin h inder their use as alternatives . Tr ansplants are grown over a five

- year cycle.

Southeastern U nited S tates nurseries in North Carolina and Tennessee produce transplants for Florida grown in open fields. An individual field is planted to strawberries once every three years. Although methyl b romide is not identified as the required fumigant in North Carolina and23

Tennessee, growers have not had any experience in alternative use that can be relied upon to ensure stock certification. To attain certification of transplants, commercially feasible p rotocols must be developed and tested and sanctioned by state regulators. 

### Sweet Potato Slips Methyl bromide CUEs for the production of sweet potato slips has decreased by 94% from 2005 (see Figure 15)

.

Figure 1 5. Reduction in CUEs for sweet potato slips

. Sweet potato production in California has two distinct components: transplant production and field production. Greater weed and disease control is required in the transplant nursery. Field production utilizes low rate application (12 to 15 gallons per ac re) of 1
, 3

- D without tarping to control nematodes. Field production of sweet potatoes in California is concentrated in a relatively small geographic area in the central part of the state and results in exceeding the current use allotment of 1,3

- D allowed w ithin a township (640 acres ). T he soil where sweet potato “slips” (transplants) are grown is typically fumigated from November through January in order to meet a market window. In addition, the growers who fumigate in November do not have 1,3

- D available because the township cap has been exceeded by other crops that fumigate earlier in the year. Unfortunately, 1,3

- D is largely unavailable for regulatory reasons for use in the fall when fumigation occurs, making methyl bromide use critical.



### Tomato Methyl bromide CUEs in tomatoes ha ve been reduced by 88% from 2005 levels (see Figure 16)

. US tomato growers have been reducing methyl bromide use rates in all production areas

.24

Figure 16. Reduction in CUEs for tomatoes

. Iodomethane formulated with chloropicrin has shown good efficacy against key tomato pests, including nutsedge, in a number of trials with tomato and related vegetables such as peppers (e.g., Louws et al. 2006, Culpepper 2006, 2007, 2008, Culpepper et al. 2008, Olsen 2008). The primary fumigant alternatives for methyl bromide that have shown promise against key tomato pests include the spring application of the fumigant combination of 1,3

- D + chloropicrin, followed by chloropicrin alone, followed by metam

- sodium and the newly registered fumigant iodomethane. The application of a sequential 3 way fumigant combination, the “Georgia 3 Way” (consisting of 1,3

- D + chloropicrin, followed by chloropicrin, followed by metam

- sodium or
metam

- potassium), continues to be evaluated. It is considered to be usef ul as a spring applied fumigant mix in the state of Georgia. It should be noted that a major part of developing a commercially feasible protocol to use this system in all regions will require adjustment of rates and application timing for field and strip a pplications. The increased production costs, and cost of new or altered equipment needed for application might delay the adoption of the three fumigant mix.
Some production areas in Florida are located above karst topographic formations which places
restr ictions on the use of 1,3

- D. Stinging nematode problems require either methyl bromide or 1,3

- D. For Florida, Georgia and Mid

- Atlantic States, Maryland growers, in common with other tomato growers in the mid

- Atlantic region, have production areas with high water tables and in close proximity to environmentally sensitive estuaries; these factors make the use of 1,3

- D limited, and thus the three fumigant combination cannot be considered as an alternative.
Iodomethane can be an efficacious alternative, but prot ocols have not been sufficiently established. Given sufficient time to transition
, this fumigant can be worked into the production system. In the S outheast ern U nited S tates , there is concern about injury and delayed planting. For these regions, there are s everal economic drawbacks that include the cost of iodomethane, the cost of using VIF or metalized mulches, and an initial cost of some minor equipment alteration.25 

# Current Research

USDA has several grant programs that support research into overcoming ob stacles that have prevented the implementation of methyl bromide alternatives. National Program 308, Methyl Bromide Alternatives , supports research in soil

- borne plant pathology, post

- harvest entomology, plant pathology, and plant physiology in a national research program to develop alternatives to the agricultural uses of methyl bromide. Since currently registered, chemically based alternative systems face existing and potential problems associated with township use limitations, emission control, and buffe r zone restrictions, performance of alternative fumigants needs to be evaluated in two ways: 1) Under controlled laboratory or small plot conditions where relationships among fumigant concentration, exposure time, environmental conditions, pest species, an d growth stage need to be determined; and 2) In the field, where factors such as chemical distribution, pest population density and distribution, pest interactions, and environmental and soil conditions influence efficacy. Knowledge on emission characteri stics and efforts to control emissions through fumigant application technology needs to be expanded.

A lthough a substantial amount of work has been done with many the alternative fumigants, the lack of consistent performance across crops, pests, regions, s oil types, and soil water content reduces the likelihood of their adoption. Factors impacting efficacy are poorly characterized. New materials that are nearing registration have not been adequately tested in all crops and regions and over multiple croppi ng cycles. The USDA is funding research to i mprove understanding of the impact of fumigant concentration, movement through soil, pest exposure time, soil temperature, soil moisture, soil type, and pest species on fumigant efficacy. Improved fumigant appli cation methods to reduce emissions and enhance efficacy with less potential for negative environmental impacts.
The USDA is funding additional research on post

- harvest use of methyl bromide working to reduce the need to fumigate with methyl bromide and is developing potential chemical and non

chemical replacement treatments. Similar research is underway to define the efficacy of the newly registered alternative for use in structural fumigations. S ulfuryl fluoride has been registered for use in structural fa cilities, but efficacy studies are still needed to optimize its use in different types of facilities and to determine its economic feasibility

. For durable commodities such as dried fruit and nuts, chemical treatments being investigated include new chemica ls such as sulfuryl fluoride, propylene oxide, and new techniques using phosphine at cold temperature. Non

- chemical alternatives for durable commodities that will be researched include infrared heating, cold, a new CATTS (hot air plus controlled atmospher e) treatment of fresh fruit, and compression combined with phosphine for treatment of hay going to Japan. Other technologies are in various stages of research and may add to the growing list of potential treatments. In26

addition to chemical and physical t reatments, IPM methods that eliminate pests in the field before they infest fruit or nuts are being investigated.
Numerous options for knowledge

- sharing and research exist. USEPA and USDA continue to f und the annual meeting on methyl bromide alternatives. At th e 2008, sessions focused on

asse s sing and prioritize research needs and d evelop ing use and emission minimization agenda for methyl bromide alternatives research. The Methyl Bromide Transitions g rants program has provided over $9 million for research i n 2007, 2008, and 2009

. Additionally, the Crops at Risk program (CAR) and the RAMP prog rams have directly and indirectl y provided for methyl bromide alternative research over $17 million in 2009 alone.