NOMINATING PARTY: The United States of America

NAME USA CUN12 SOIL TOMATOES Open Field 

BRIEF DESCRIPTIVE TITLE OF NOMINATION: 

Methyl Bromide Critical Use Nomination for Pre-plant Soil Use for Tomato Grown in Open 

Fields (Submitted in 2010 for 2012 Use Season) 

CROP NAME (OPEN FIELD OR PROTECTED): Tomatoes Open Field

QUANTITY OF METHYL BROMIDE REQUESTED: 

TABLE 1: QUANTITY OF METHYL BROMIDE REQUESTED IN EACH YEAR OF NOMINATION

Year NOMINATION AMOUNT (KILOGRAMS) 

2012 54,423 kg 

NOMINATING PARTY CONTACT DETAILS: 

Contact Person: John Thompson 

Title: Division Director 

Address: Office of Environmental Policy 

U.S. Department of State 

2201 C Street, N.W. Room 2658 

Washington, D.C. 20520 

 U.S.A. 

Telephone: (202) 647-9799 

Fax: (202) 647-5947 

E-mail: thompsonje2@state.gov 

Following the requirements of Decision IX/6 paragraph (a)(1) The United States of America has determined that the 

specific use detailed in this Critical Use Nomination is critical because the lack of availability of methyl bromide for 

this use would result in a significant market disruption. . ■ Yes  No 

 

Signature Name Date 

Title: 

(Details on this page are requested under Decision Ex. I/4(7), for posting on the Ozone Secretariat website under 

Decision Ex. I/4(8).) 

This form is to be used by holders of single-year exemptions to reapply for a subsequent year’s exemption (for 

example, a Party holding a single-year exemption for 2005 and/or 2006 seeking further exemptions for 2007). It 

does not replace the format for requesting a critical-use exemption for the first time. 

In assessing nominations submitted in this format, TEAP and MBTOC will also refer to the original nomination on 

which the Party’s first-year exemption was approved, as well as any supplementary information provided by the 

Party in relation to that original nomination. As this earlier information is retained by MBTOC, a Party need not 

re-submit that earlier information. 

CONTACT OR EXPERT(S) FOR FURTHER TECHNICAL DETAILS: 

USA CUN12 SOIL TOMATOES Open Field Page 1 of 27
Contact/Expert Person: Jack Housenger 

Title: 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) 308-8200 

Fax: (703) 308-7042 

E-mail: Housenger.Jack@epa.gov

 

LIST OF DOCUMENTS SENT TO THE OZONE SECRETARIAT IN OFFICIAL NOMINATION PACKAGE: 

1. PAPER DOCUMENTS: 

Title of paper documents and appendices 

No. of pages Date sent to Ozone 

Secretariat 

USA CUN12 SOIL TOMATOES Open Field 27 

2. ELECTRONIC COPIES OF ALL PAPER DOCUMENTS: 

*Title of each electronic file (for naming convention see notes above) 

No. of 

kilobytes 

Date sent to Ozone 

Secretariat 

USA CUN12 SOIL TOMATOES Open Field 

* Identical to paper documents 

USA CUN12 SOIL TOMATOES Open Field Page 2 of 27
METHYL BROMIDE CRITICAL USE RENOMINATION FOR 

PREPLANT SOIL USE (OPEN FIELD OR PROTECTED ENVIRONMENT) 

TOMATOES 

1. SUMMARY OF THE NEED FOR METHYL BROMIDE AS A CRITICAL USE 

This nomination is for methyl bromide use in the production of tomatoes in Florida, Georgia, 

The Mid-Atlantic (Maryland, and Virginia), and the Southeast. U.S. tomato growers have been 

reducing methyl bromide use rates in all production areas. 

The USG has reviewed all factors affecting transition rates in this sector. Based on this 

assessment the transition rate has been greatly increased for most portions of this sector. For the 

area covered in this nomination, the USG believes that the narrative discussion included in this 

document is technically valid. The USG has nominated amounts of methyl bromide based only 

on those sub-sectors that cannot transition away from methyl bromide at the accelerated rate. 

The primary fumigant alternatives for methyl bromide that have shown promise against key 

tomato pests the spring application of the fumigant combination of 1,3 D, followed by 

chloropicrin alone, followed by metam-sodium and the newly registered fumigant iodomethane. 

Current research has demonstrated that in many cases iodomethane (MIDAS®) formulated with 

chloropicrin can be an efficacious methyl bromide alternative, however, transition time will be 

needed for many tomato producers to adapt production to using this material. Growers will need 

this time to adapt to the use of new application equipment appropriate to the lower flow rates 

typical with iodomethane, to retro-fit equipment in order to avoid corrosion by iodomethane, etc. 

Increased costs due to using iodomethane are described in the "economic assessment" section 

below. 

For 2009, crop experts at the University of Georgia reported that the price of iodomethane went 

up so dramatically that they did not advise growers to use the product, despite its good efficacy. 

It is not clear whether or not these high prices affected other tomato growing regions included in 

this nomination, or how long the high prices will persist. However, at the very least, this 

information does suggest that adoption of iodomethane by tomato growers will be significantly 

affected by price fluctuations. Application protocols have not been sufficiently established due to 

limited results of long term on-farm research. A major concern with the use of iodomethane is 

the potential increase of plant-back timing to avoid potential crop injury and loss. 

In other recent work, some research results with dimethyl disulfide (DMDS) indicate that this 

fumigant is promising. However, preliminary research results from a single year of fumigation in 

pepper production demonstrate that, as a stand-alone product, the efficacy of DMDS is not 

comparable to methyl bromide and will require chloropicrin (MacRae and Culpepper, 2008). 

Treatments with DMDS plus chloropicrin and/or metam-sodium are not significantly different 

from methyl bromide + chloropicrin. In any case, this fumigant is not registered in the US and 

therefore cannot at this time be considered a practical methyl bromide alternative. 

USA CUN12 SOIL TOMATOES Open Field Page 3 of 27
The application of a sequential 3 way fumigant combination, the “Georgia 3 Way” (consisting of 

1,3-D, followed by chloropicrin, followed by metam-sodium or metam-potassium), continues to 

be evaluated. It is considered to be useful 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 applications. Trials evaluating the “Georgia 3 Way” show that it can be as efficacious 

against key southern US tomato pests as methyl bromide and/or iodomethane + chloropicrin. An 

exception to this is a study by Chellemi (2008) where, in some trials, pepper plant height and 

yield was reduced due to crop injury. However, the injury was later correlated with high levels of 

soil potassium and probably not a direct result of the fumigation. Weed and nematode control 

for the “Georgia 3 Way” as compared to methyl bromide were not different. Adding to the slow 

adoption of this system is the lack of established protocol that will be based on mitigating 

potential problems such as plant-back timing, soil moisture, and location/edaphic variability. 

The increased production costs, and cost of new or altered equipment needed for application will 

also be an impediment to adoption of the three fumigant mix. 

Florida 

Some production areas in Florida are located above karst topographic formations which places 

restrictions on the use of 1,3-D. Stinging nematode problems require either methyl bromide or 

1,3-D. Some fields with key disease problems have achieved good control with chloropicrin, 

although there may be regulatory restrictions on its use at high rates. Where 1,3-D is allowed, 

the application of the three fumigant mix continues to be evaluated but is not considered a viable 

alternative. 

Preliminary research has demonstrated that iodomethane can be an efficacious methyl bromide 

alternative, but protocols have not been sufficiently established. Given sufficient time to 

transition this fumigant can be worked into the production system. 

Georgia 

The three way fumigant combination (the ‘Georgia 3 Way’) continues to be evaluated, and has 

proven to be efficacious for spring application in Georgia. However, the lack of established 

protocol and the cost of new or altered equipment have been a limiting factor in the adoption of 

this fumigant combination. 

Preliminary research has demonstrated that iodomethane can be an efficacious methyl bromide 

alternative, but protocols have not been sufficiently established. Given sufficient time to 

transition these fumigants can be worked into the production system. 

Mid-Atlantic 

Current research in this region has not been submitted and it is thus assumed that the use of 

iodomethane as a methyl bromide replacement, given time to transition, will be sufficient. 

However, just as in many areas of the country, the establishment of protocols will slow farmer 

USA CUN12 SOIL TOMATOES Open Field Page 4 of 27
adoption. Until results from on-farm research projects have established a protocol a period of 

transition will be needed. 

Southeast 

The “Georgia 3 Way” fumigant combination continues to be evaluated in the southeast. In a 

comment by Craig Anderson of the University of Arkansas, the cool temperatures and wet soils 

in early spring will extend the plant back timing due to the additional time needed for soil 

fumigant levels to dissipate to avoid crop injury and subsequent yield loss (Toth, 2008) 

Preliminary research conducted in states other than those in the southeast have demonstrated that 

iodomethane can be an efficacious methyl bromide alternative, but protocols have not been 

sufficiently established. Concerns in the southeast about injury and delayed planting have lead 

some to question their usefulness in this region. Currently, there are several 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. 

2. SUMMARIZE WHY KEY ALTERNATIVES ARE NOT FEASIBLE 

Our review of available research on other methyl bromide alternatives discussed by MBTOC for 

tomatoes suggests that, of the registered (i.e., legally available) chemistries, iodomethane, and 

combinations of metam sodium, 1,3-D, and/or chloropicrin have shown some potential as 

commercially viable replacement to methyl bromide. Non-chemical alternatives are either not 

viable for US tomatoes or require more research and commercial development before they can be 

technically and economically feasible. For some areas in the state of Georgia, a 3 way fumigant 

combination of 1,3 D, followed by chloropicrin alone, followed by metam-sodium, has shown 

promise against key tomato pests in spring season only fumigation. However, the 

aforementioned fumigant combination has not met with success in other areas of the southeast. 

The transition rate included in the BUNNIE incorporates an estimate of projected use of this 

strategy as well as the use of iodomethane. 

Many of the alternatives require the evaluation of their relationship between fumigant 

alternatives, various mulches, and herbicide systems under different growing conditions. From 

this information on-farm protocols can be established. 

Alternatives are considered not feasible where: 

1) they have not been sufficiently tested or protocols have not been sufficiently developed for 

their use 

2) costs are excessive 

3) application difficulties exist due to such factors as equipment requirements 

4) pest pressure is so high that alternatives are not effective 

5) not registered for use in the US (such as DMDS). 

6) There are significant restrictions on which crops can be rotated through after use of a given 

alternative (e.g., halosulfuron has rotational restrictions that prevent its use in southeastern 

US tomatoes). 

USA CUN12 SOIL TOMATOES Open Field Page 5 of 27
7) Resistance management prevents use of the alternative (e.g., glyphosate resistant weeds, such 

as Amaranth, in the southern US, prevent use of this alternative as a post-emergent weed 

control in those regions). 

The US nomination is only for those areas where the alternatives are still under extensive 

evaluation and pest pressure is high. In US tomato production there are several factors that make 

some of the assumed alternatives, other than iodomethane, unsuitable. These include: 

1) Pest control efficacy of alternatives: the efficacy of alternatives may not be 

comparable to methyl bromide in some areas, making these alternatives technically 

and/or economically infeasible for use in tomato production. 

2) Geographic distribution of key target pests: i.e., some alternatives may be comparable 

to methyl bromide as long as key pests occur at low pressure. The US is only 

nominating a CUE for tomato where the key pest pressure is moderate to high such as 

nutsedge in the Southeastern US. 

3) Regulatory constraints: e.g., in Florida due to the presence of karst topographical 

features. 

4) In Virginia and much of the mid-Atlantic, high water tables and the close proximity of 

production areas to environmentally sensitive estuaries makes the use of 1,3-D 

limited. 

5) Delay in planting and harvesting: e.g., the plant-back interval for telone+chloropicrin 

is two weeks longer than methyl bromide+chloropicrin. Delays in planting and 

harvesting result in users missing key market windows, and adversely affect revenues 

through lower prices. 

6) Alternatives that are nonselective are restrictive as a preplant burndown only. 

3. IS THE USE COVERED BY A CERTIFICATION STANDARD? 

Not used to meet a certification standard. 

4. IF PART OF THE CROP AREA IS TREATED WITH METHYL BROMIDE, 

INDICATE THE REASON WHY METHYL BROMIDE IS NOT USED IN THE OTHER 

AREA, AND IDENTIFY WHAT ALTERNATIVE STRATEGIES ARE USED TO 

CONTROL THE TARGET PATHOGENS AND WEEDS WITHOUT METHYL 

BROMIDE THERE. 

In the areas where methyl bromide is not currently used there is often low weed and/or pathogen 

pressure and/or no restrictions on 1,3-D use. In areas where 1,3-D can be used, there are a many 

growers have cooperated with universities and others on developing application protocols 

specific to their conditions for the 3 way fumigant combination (1,3 D, followed by chloropicrin 

alone, followed by metam-sodium). 

USA CUN12 SOIL TOMATOES Open Field Page 6 of 27
5. WOULD IT BE FEASIBLE TO EXPAND THE USE OF THESE METHODS TO 

COVER AT LEAST PART OF THE CROP THAT HAS REQUESTED USE OF 

METHYL BROMIDE? WHAT CHANGES WOULD BE NECESSARY TO ENABLE 

THIS? 

No, areas that use methyl bromide do so because environmental sensitivity and/or heavy pest 

pressure preclude the use of fumigants that are employed when these conditions are not present. 

The USG has reviewed all factors affecting transition rates in this sector. Based on this 

assessment the transition rate has been greatly increased for most portions of this sector. For the 

area covered in this nomination, the USG believes that the narrative discussion included in this 

document is technically valid. The USG has nominated amounts of methyl bromide based only 

on those sub-sectors that cannot transition away from methyl bromide at the accelerated rate. 

Researchers are continuing to evaluate fumigant concentration and mulch interaction using the 3 

way fumigation combination and iodomethane (Culpepper et al, 2007). However, there is still 

the need for more research to determine the fumigant rates and mulch combinations needed for 

pest control and crop safety where there is heavy pest pressure. In a study by Culpepper 

(Georgia CUE appendix 2011; see Appendix A for a reproduction of this submission), the 3 way 

fumigant combination resulted in tomato plant heights that were lower than the methyl bromide 

treated plots. When using the Blockade mulch (low permeability tarp) injury was severe with 

plant damage and tomato yields being reduced even when the soil was allowed to air, but they 

have seen good results in spring applications. This is similar to information provided by growers 

and university personnel in the southeast (Toth, 2008) 

TABLE 2. TOMATO PLANT YIELDS AND HEIGHT IN RESPONSE TO TIME OF PLANTING AFTER FUMIGATING. 

Fumigant Mulch Planting days after 

fumigation 

Gas in bed at 

planting 

(ppm) 

Yield 

(#/plot, highest value 

fruit only; no difference 

noted with total fruit) 

Heights (cm) 

(3 wk after planting) 

MB LDPE 7 29 127 a 38 a 

3-WAY LDPE 7 77 127 a 32 cd 

3-WAY Blockade 7 368 55 c 14 f 

MB LDPE 7 + 1 2 117 a 37 ab 

3-WAY LDPE 7 + 1 13 132 a 33 cd 

3-WAY Blockade 7 + 1 31 99 b 27 e 

MB LDPE 14 2 142 a 37 ab 

3-WAY LDPE 14 4 132 a 34 bc 

3-WAY Blockade 14 38 114 a 30 de 

MB LDPE 14 + 1 0 133 a 35 abc 

3-WAY LDPE 14 + 1 3 127 a 33 cd 

3-WAY Blockade 14 + 1 27 119 a 30 de 

Source: Georgia CUE Appendix; see Appendix A for a reproduction of this submission. 

Developing a protocol for this system includes the titration of rates for field and strip 

applications (table 3). In preliminary data comparing the 3 fumigant combination, results have 

demonstrated that methyl bromide and iodomethane do not significantly differ in efficacy. 

However variability among results across locations demonstrates the need for further research 

(Toth, 2008). An exception to these findings was a study by Chellemi (2008) where pepper plant 

USA CUN12 SOIL TOMATOES Open Field Page 7 of 27
height and yield was reduced due to crop injury; however, the injury was later correlated with 

high levels of soil potassium and probably not a direct result of the fumigation. On the other 

hand, in three of the trials weed and nematode control for the three fumigant combination and 

methyl bromide were low; less than 0.01 weeds / foot of row and nematode concentration was 

less than 1.0 / 100 cc of soil. 

TABLE 3. UGA Three FUMIGANT COMBINATION Adjusted Rates 11-2008. 

Fumigant(s) Rate 

(lb/acre) 

Rate Adjusted for Strip 

Treatment (lb / acre) 

Method 

Methyl Bromide 143 

Chloropicrin 143 

83 

83 

bedded, shank, standard tarp 

Methyl Bromide 143 

Chloropicrin 143 

83 

83 

bedded, shank, 

high barrier tarp 

1,3-Dichloropropene 171 

Chloropicrin 150 

Metam Sodium 320 

99 

87 

186 

bedded, shank, standard tarp 

1,3-Dichloropropene 171 

Chloropicrin 150 

Metam Sodium 320 

99 

87 

186 

bedded, shank, 

high barrier tarp 

Source: Rates and application methods represent likely scenarios based on information from USDA NASS, EPA 

proprietary data, and/or stakeholder-submitted comments. 

Table taken from Georgia CUE Appendix; see Appendix A for a reproduction of this submission. 

Tomato growers in Maryland have again requested methyl bromide. These growers have 

historically used methyl bromide in their tomato production, purchasing it from the stockpile 

since the 2005 ban. Maryland growers, in common with other tomato growers in the midAtlantic 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. 

Techniques such as grafting, resistant rootstocks immune to target fungal pathogens, plant 

breeding, soil-less culture, organic production, substrates, plug, are not commercially feasible. 

Availability of such transplants is further hampered by the lack of infrastructure to make grafted 

tomato plants available on a large scale, concomitant with this is the high premium associated 

with these transplants at this time. Grafting and plant breeding are thus also rendered technically 

infeasible as methyl bromide alternatives for control of fungal pathogens, nutsedges and 

nematodes. Grafting of solanaceous plants is relatively new to US growers, and has met with a 

great deal of concern regarding the potential for the establishment of off-type plants developing 

from the rootstock and/or fruit seeds. N. Burell et al. (2008) evaluated various grafted tomato 

cultivars in fields where iodomethane, DMDS, or methyl bromide were applied. The results of 

their research demonstrated that regardless of rootstock, yields of tomato plants responded 

equally without regard to fumigant type. In this case it would seem that the steady pace of on 

going transitioning to alternative herbicides such as iodomethane would be more advantageous to 

pursue. 

USA CUN12 SOIL TOMATOES Open Field Page 8 of 27
6. SUMMARY OF RECENT RESEARCH 

As mentioned earlier in this document, 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). Iodomethane had time limitations removed from its federal 

label in October, 2008, and has received state-level approval in 47 US states (California, 

Washington, and New York are the exceptions at this time). However, other important 

constraints must be considered when assessing the feasibility of iodomethane as a methyl 

bromide alternative. These include: (1) the cost of iodomethane formulations is higher than 

methyl bromide, and will probably remain so for the next several years, (2) growers and 

researchers will need time to evaluate iodomethane use in the various local production conditions 

covered by this nominations, and (3) growers and applicators will need to make some equipment 

modifications to adapt to the lower flow rates typical with less expensive iodomethane 

application rates and to avoid the corrosion of some metals that can occur with iodomethane

(Sumner 2005, Noling et al. 2006). The economic impact of using iodomethane is further 

described in item 7 in this document (below). A consideration of these aspects has led the USG 

to conclude that while iodomethane appears to be technically feasible to manage key tomato 

pests in all parts of the US where it has been registered, time will be needed for growers and 

extension service experts to adapt its use successfully. Therefore, the amount of methyl bromide 

nominated for tomato has been adjusted downward while also considering the time needed to 

transition to iodomethane. 

Performance data presented by B. Olsen at the November 2008 MBAO conference reported 

tomato yield data from 12 field sites where the average increase in yields from iodomethane 

treated plots over methyl bromide treated plots was 11 percent. Ten of the 12 study sites were in 

the southeast. It must be noted that there was no statistical analysis present with this data and as 

such there is no confirmation on whether this reported average increase in yields is significant. 

Despite these results, representatives of the southeast tomato growers’ consortia are currently 

cautious about recommending iodomethane as a methyl bromide replacement (Toth, 2008). 

Research conducted in Georgia demonstrated that, in small plots, purple nutsedge control for 

methyl bromide, iodomethane, and DMDS were not significantly different under LDPE, 

metalized, or VIF mulch (table 4). Yields of pepper and cucumber plants fumigated with 

iodomethane under VIF were not different from yields for untreated plots (Culpepper et al, 

2007). The reader should keep in mind here that DMDS is not registered for use in the USA. 

In a study by Chellemi (2008), pepper plant height and yield was reduced due to crop injury. 

However, the injury was later correlated with high levels of soil potassium and probably not a 

direct result of the fumigation. In this same study, three of the four trials reported weed and 

nematode control for the three fumigant combination and methyl bromide at less than 0.01 weeds 

/ foot of row and nematode concentration at less than 1.0 / 100 cc of soil. 

USA CUN12 SOIL TOMATOES Open Field Page 9 of 27
TABLE 4. PURPLE NUTSEDGE PLANTS IN SMALL PLOT PEPPER CROP (20 SQ FT) 

Mulch 

*Fumigant(s) LDPE Metalized VIF 

Methyl Bromide 0.5 a 0.0 a 0.3 a 

Iodomethane 0.8 a 0.3 a 0.8 a 

DMDS 2.5 a 0.5 a 0.0 a 

Untreated 84 d 76 d 54 c 

*All fumigation treatments contain chloropicrin.Table taken from Culpepper et al (2007) 

Hausbeck and Cortright (2007) measured cucurbit plant vigor to determine fumigant/mulch 

interactions using either LPDE or VIF plastic mulch for the control of Fusarium oxysporum. Of 

the fumigants used in the study, the methyl bromide and iodomethane treatments resulted in 

cantaloupe plants with the highest vigor (Table 5). In general, treatments under LPDE had 

higher plant vigor when compared with plants grown under VIF. It is noteworthy that in this 

study VIF tarps were prone to wind removal, which reduced their reliability under some growing 

conditions. 

TABLE 5: EVALUATION OF FUMIGANTS AND PLASTIC MULCHES FOR MANAGING FUSARIUM IN 

CUCURBIT CROPS 2007 

Treatment (time after treatment to planting) Rate of 

formulated 

product 

Vigor* 

Untreated control under LDPE (5 days) 1.0-1.3 a

**

Iodomethane+chloropicrin 50:50 under LDPE (10 days) 196 kg/ha 1.0 a 

Iodomethane+chloropicrin 50:50 under VIF (10 days) 196 kg/ha 3.0 c 

Methyl bromide+chloropicrin 67:33 under LDPE (10 days) 280 kg/ha 1.0 a 

Methyl bromide+chloropicrin 67:33 under VIF (10 days) 280 kg/ha 2.7 bc 

1,3 D + chloropicrin 65:35 under LDPE (21 days) 187 liters/ha 2.3 bc 

1,3 D + chloropicrin 65:35 under VIF (21 days) 187 liters/ha 4.7 d 

Chloropicrin under LDPE (14 days) 187 liters/ha 2.7 c 

Chloropicrin under VIF (14 days) 187 liters/ha 3.3 cd 

*

Vigor rating of plant health; 1=healthy plants with no stunting, 5= moderated plant stunting with variable stand, 

10=complete plant death. 

**Column means with a letter in common are not significantly different (Fisher LSD Method; P=0.05). 

From Hausbeck and Cortright 2007. 

In addition to the limitations of VIF discussed above, the USG notes that the plant vigor in 1,3 D 

treatments in these new trials is lower than that seen in methyl bromide treatments. This is 

similar to what was seen in previous years’ tests (Hausbeck and Cortright 2004; see also 

discussion in the cucurbit nominations). 

USA CUN12 SOIL TOMATOES Open Field Page 10 of 27
USA CUN12 SOIL TOMATOES Open Field Page 11 of 27

As far as the USG has been able to determine, no other studies have been conducted since 2007 

to evaluate the technical and commercial feasibility of fumigant alternatives to methyl bromide 

for controlling F. oxysporum subtypes under production conditions relevant to the 

Maryland/Delaware regions. 

7. ECONOMIC FEASIBILITY OF ALTERNATIVES 

The following economic analysis is organized by methyl bromide critical use application 

regions. 

Readers should note that in this study net revenue is calculated as gross revenue minus operating 

costs. This is a good measure as to the direct losses of income that may be suffered by the users. 

It should be noted that net revenue does not represent net income to the users. Net income, which 

indicates profitability of an operation of an enterprise, is gross revenue minus the sum of 

operating and fixed costs. Net income should be smaller than the net revenue measured in this 

study. Fixed costs were not included because they are often difficult to measure and verify. 

Summary of Economic Feasibility 

The economic analysis of the tomato application compared data on yields, crop prices, revenues 

and costs using methyl bromide and using alternative pest control regimens in order to estimate 

the loss of methyl bromide availability. The alternatives identified as technically feasible - in 

cases of low pest infestation1

 – for different regions by the U.S. are: (a) iodomethane and (b) 1,3-

dichloropropene and chloropicrin followed by chloropicrin, followed by metamsodium/potassium (otherwise referred to as the Georgia 3-Way). 

The economic factors that drive the feasibility analysis for fresh market tomato uses of methyl 

bromide alternatives are: (1) yield losses, referring to reductions in the quantity produced, (2) 

increased production costs, which may be due to the higher-cost of using an alternative, 

additional pest control requirements, and/or resulting shifts in other production or harvesting 

practices (3) quality losses, which generally affect the quantity and price received for the goods, 

and (4) missed market windows due to plant back time restrictions, which also affect the quantity 

and price received for the goods. 

The economic reviewer then analyzed crop budgets for pre-plant sectors to determine the likely 

economic impact if methyl bromide were unavailable. Various measures were used to quantify 

the impacts, including the following: 

(1) Loss per Hectare. For crops, this measure is closely tied to income. It is relatively easy to 

measure, but may be difficult to interpret in isolation. 

(2) Loss per Kilogram of Methyl Bromide. This measure indicates the value of methyl 

bromide to crop production. 

 

1 It should be noted that the USG does not request methyl bromide for use in areas of low to moderate pest pressure. 

Only cases where key pests are present at moderate to high levels require methyl bromide for pest pressure. 
(3) Loss as a Percentage of Gross Revenue. This measure has the advantage that gross 

revenues are usually easy to measure, at least over some unit, e.g., a hectare of land or a storage 

operation. However, high value commodities or crops may provide high revenues but may also 

entail high costs. Losses of even a small percentage of gross revenues could have important 

impacts on the profitability of the activity. 

(4) Loss as a Percentage of Net Operating Revenue. We define net cash revenues as gross 

revenues minus operating costs. This is a very good indicator as to the direct losses of income 

that may be suffered by the owners or operators of an enterprise. However, operating costs can 

often be difficult to measure and verify. 

(5) Operating Profit Margin. We define operating profit margin to be net operating revenue 

divided by gross revenue per hectare. This measure would provide the best indication of the 

total impact of the loss of methyl bromide to an enterprise. Again, operating costs may be 

difficult to measure and fixed costs even more difficult, therefore fixed costs were not included 

in the analysis. 

These measures represent different ways to assess the economic feasibility of methyl bromide 

alternatives for methyl bromide users, who are tomato producers in this case. Because producers 

(suppliers) represent an integral part of any definition of a market, we interpret the threshold of 

significant market disruption to be met if there is a significant impact on commodity suppliers 

using methyl bromide. The economic measures provide the basis for making that determination. 

Eastern US 

We conclude that, at present, iodomethane would be the economically feasible alternative to 

methyl bromide for use in Eastern US tomato production in areas exhibiting karst topographical 

features. However, see the technical discussion above for a description of reasons why time will 

be needed for growers to transition to routine, commercially feasible iodomethane use. In areas 

where karst features are not present it appears that tomato growers can use a combination of 

three fumigants applied sequentially (1,3-D, chloropicrin, and metam-sodium/potassium) and 

achieve yields that are comparable to those produced by using methyl bromide for spring crops 

only. The USG factored this new technique into their request by adding a four year transition 

(assuming that all non-karst spring fumigations for tomatoes in the Southeast will transition 

away from methyl bromide over four years) for spring fumigations. 

USA CUN12 SOIL TOMATOES Open Field Page 12 of 27
TABLE 6. VIRGINIA: ECONOMIC IMPACTS OF METHYL BROMIDE ALTERNATIVES 

VIRGINIA TOMATO GROWERS METHYL 

BROMIDE

Iodomethane GA – 3 WAY 

METHOD

PRODUCTION LOSS (%) 0% 0% 0% 

 PRODUCTION PER HECTARE (CWT) 920 920 920 

* PRICE PER UNIT (US$) $ 33 $ 33 $ 33 

= GROSS REVENUE PER HECTARE (US$) $ 29,902 $ 29,902 $ 29,902 

- OPERATING COSTS PER HECTARE (US$)* $ 26,907 $ 28,354 $ 27,687 

= NET REVENUE PER HECTARE (US$) $ 2,995 $ 1,548 $ 2,215 

1. LOSS PER HECTARE (US$) $ - $ 1,447 $ 780 

2. LOSS PER KILOGRAM OF METHYL BROMIDE 

(US$) $ - $ 17 $ 9 

3. LOSS AS A PERCENTAGE OF GROSS REVENUE 

(%) 0% 5% 3% 

4. LOSS AS A PERCENTAGE OF NET OPERATING 

REVENUE (%) 0% 48% 26% 

5. OPERATING PROFIT MARGIN (%) 10% 5% 7% 

*Note that the measures in the tables below must be interpreted carefully. Operating costs do not include fixed costs 

and net revenue equals gross revenue minus operating costs.

TABLE 7. MARYLAND: ECONOMIC IMPACTS OF METHYL BROMIDE ALTERNATIVES

MARYLAND TOMATO GROWERS METHYL 

BROMIDE

Iodomethane GA – 3 WAY 

METHOD

PRODUCTION LOSS (%) 0% 0% 0% 

 PRODUCTION PER HECTARE (BOX 25LBS) 4,953 4,953 4,953 

* PRICE PER UNIT (US$) $ 7 $ 7 $ 7 

= GROSS REVENUE PER HECTARE (US$) $ 35,287 $ 35,287 $ 35,287 

- OPERATING COSTS PER HECTARE (US$)* $ 30,269 $ 31,969 $ 31,888 

= NET REVENUE PER HECTARE (US$) $ 5,018 $ 3,319 $ 3,399 

1. LOSS PER HECTARE (US$) $ - $ 1,699 $ 1,619 

2. LOSS PER KILOGRAM OF METHYL BROMIDE 

(US$) $ - $ 23 $ 22 

3. LOSS AS A PERCENTAGE OF GROSS REVENUE 

(%) 0% 5% 5% 

4. LOSS AS A PERCENTAGE OF NET OPERATING 

REVENUE (%) 0% 34% 32% 

5. OPERATING PROFIT MARGIN (%) 14% 9% 10% 

*Note that the measures in the tables below must be interpreted carefully. Operating costs do not include fixed costs 

and net revenue equals gross revenue minus operating costs.

Error! Bookmark not defined.

USA CUN12 SOIL TOMATOES Open Field Page 13 of 27
TABLE 8. SOUTHEASTERN US: ECONOMIC IMPACTS OF METHYL BROMIDE ALTERNATIVES

SOUTHEASTERN TOMATO CONSORTIUM 

** 

METHYL 

BROMIDE

Iodomethane GA – 3 WAY 

METHOD

PRODUCTION LOSS (%) 0% 0% 0% 

 PRODUCTION PER HECTARE (BOX 25LBS) 4,942 4,942 4,942 

* PRICE PER UNIT (US$) $ 7 $ 7 $ 7 

= GROSS REVENUE PER HECTARE (US$) $ 35,830 $ 35,830 $ 35,830 

- OPERATING COSTS PER HECTARE (US$)* $ 33,913 $ 35,428 $ 34,762 

= NET REVENUE PER HECTARE (US$) $ 1,918 $ 402 $ 1,069 

1. LOSS PER HECTARE (US$) $ - $ 1,516 $ 849 

2. LOSS PER KILOGRAM OF METHYL BROMIDE 

(US$) $ - $ 20 $ 11 

3. LOSS AS A PERCENTAGE OF GROSS REVENUE 

(%) 0% 4% 2% 

4. LOSS AS A PERCENTAGE OF NET OPERATING 

REVENUE (%) 0% 79% 44% 

5. OPERATING PROFIT MARGIN (%) 5% 1% 3% 

*Note that the measures in the tables below must be interpreted carefully. Operating costs do not include fixed costs 

and net revenue equals gross revenue minus operating costs.

** Includes: South-Eastern United States (Alabama, Arkansas, Kentucky, Louisiana, Mississippi, North Carolina, 

South Carolina, and Tennessee). 

TABLE 9. GEORGIA: ECONOMIC IMPACTS OF METHYL BROMIDE ALTERNATIVES

GEORGIA FRUIT & VEGETABLE 

GROWERS ASSOCIATION 

METHYL 

BROMIDE

Iodomethane GA – 3 WAY 

METHOD

PRODUCTION LOSS (%) 0% 0% 0% 

 PRODUCTION PER HECTARE (BOX 25LBS) 6,830 6,830 6,830 

* PRICE PER UNIT (US$) $ 9 $ 9 $ 9 

= GROSS REVENUE PER HECTARE (US$) $ 58,342 $ 58,342 $ 58,342 

- OPERATING COSTS PER HECTARE (US$)* $ 56,522 $ 57,763 $ 58,178 

= NET REVENUE PER HECTARE (US$) $ 1,820 $ 578 $ 164 

1. LOSS PER HECTARE (US$) $ - $ 1,241 $ 1,656 

2. LOSS PER KILOGRAM OF METHYL BROMIDE 

(US$) $ - $ 8 $ 11 

3. LOSS AS A PERCENTAGE OF GROSS REVENUE 

(%) 0% 2% 3% 

4. LOSS AS A PERCENTAGE OF NET OPERATING 

REVENUE (%) 0% 68% 91% 

5. OPERATING PROFIT MARGIN (%) 3% 1% 0% 

*Note that the measures in the tables below must be interpreted carefully. Operating costs do not include fixed costs 

and net revenue equals gross revenue minus operating costs.

Florida 

We conclude that, at present, iodomethane would be the economically feasible alternative to 

methyl bromide for use in Florida tomato production in areas of karst topography. Where karst 

USA CUN12 SOIL TOMATOES Open Field Page 14 of 27
features are not present the USG assumed that the sequential application of the three chemicals 

(discussed above) would have results that are similar to the performance of methyl bromide for 

spring plantings. Consequently, as described above, the transition was adjusted to account for 

the new combination

TABLE 10. FLORIDA NORTH: ECONOMIC IMPACTS OF METHYL BROMIDE ALTERNATIVES

FLORIDA FRUIT & VEGETABLE 

ASSOCIATION – NORTH FLORIDA 

METHYL 

BROMIDE

Iodomethane GA – 3 WAY 

METHOD

PRODUCTION LOSS (%) 0% 0% 0% 

 PRODUCTION PER HECTARE (BOX 25LBS) 3,548 3,548 3,548 

* PRICE PER UNIT (US$) $ 10 $ 10 $ 10 

= GROSS REVENUE PER HECTARE (US$) $ 34,874 $ 34,874 $ 34,874 

- OPERATING COSTS PER HECTARE (US$)* $ 30,804 $ 32,515 $ 31,848 

= NET REVENUE PER HECTARE (US$) $ 4,070 $ 2,359 $ 3,026 

1. LOSS PER HECTARE (US$) $ - $ 1,711 $ 1,044 

2. LOSS PER KILOGRAM OF METHYL BROMIDE 

(US$) $ - $ 20 $ 12 

3. LOSS AS A PERCENTAGE OF GROSS REVENUE 

(%) 0% 5% 3% 

4. LOSS AS A PERCENTAGE OF NET OPERATING 

REVENUE (%) 0% 42% 26% 

5. OPERATING PROFIT MARGIN (%) 12% 7% 9% 

*Note that the measures in the tables below must be interpreted carefully. Operating costs do not include fixed costs 

and net revenue equals gross revenue minus operating costs. 

TABLE 11. FLORIDA RUSKIN PALMETTO: ECONOMIC IMPACTS OF METHYL BROMIDE ALTERNATIVES

FLORIDA FRUIT & VEGETABLE 

ASSOCIATION – RUSKIN PALMETTO 

METHYL 

BROMIDE

Iodomethane GA – 3 WAY 

METHOD

PRODUCTION LOSS (%) 0% 0% 0% 

 PRODUCTION PER HECTARE (BOX 25LBS) 3,548 3,548 3,548 

* PRICE PER UNIT (US$) $ 10 $ 10 $ 10 

= GROSS REVENUE PER HECTARE (US$) $ 34,874 $ 34,874 $ 34,874 

- OPERATING COSTS PER HECTARE (US$)* $ 32,722 $ 33,452 $ 32,785 

= NET REVENUE PER HECTARE (US$) $ 2,152 $ 1,422 $ 2,089 

1. LOSS PER HECTARE (US$) $ - $ 730 $ 63 

2. LOSS PER KILOGRAM OF METHYL BROMIDE 

(US$) $ - $ 7 $ 1 

3. LOSS AS A PERCENTAGE OF GROSS REVENUE 

(%) 0% 2% 0% 

4. LOSS AS A PERCENTAGE OF NET OPERATING 

REVENUE (%) 0% 34% 3% 

5. OPERATING PROFIT MARGIN (%) 6% 4% 6% 

*Note that the measures in the tables below must be interpreted carefully. Operating costs do not include fixed costs 

and net revenue equals gross revenue minus operating costs.

USA CUN12 SOIL TOMATOES Open Field Page 15 of 27
TABLE 12. FLORIDA PALM BEACH: ECONOMIC IMPACTS OF METHYL BROMIDE ALTERNATIVES

FLORIDA FRUIT & VEGETABLE 

ASSOCIATION – PALM BEACH 

METHYL 

BROMIDE

Iodomethane GA – 3 WAY 

METHOD

PRODUCTION LOSS (%) 0% 0% 0% 

 PRODUCTION PER HECTARE (BOX 25LBS) 4,666 4,666 4,666 

* PRICE PER UNIT (US$) $ 11 $ 11 $ 11 

= GROSS REVENUE PER HECTARE (US$) $ 50,152 $ 50,152 $ 50,152 

- OPERATING COSTS PER HECTARE (US$)* $ 48,230 $ 49,197 $ 48,530 

= NET REVENUE PER HECTARE (US$) $ 1,922 $ 955 $ 1,622 

1. LOSS PER HECTARE (US$) $ - $ 967.11 $ 300.23 

2. LOSS PER KILOGRAM OF METHYL BROMIDE 

(US$) $ - $ 8.63 $ 2.68 

3. LOSS AS A PERCENTAGE OF GROSS REVENUE 

(%) 0% 2% 1% 

4. LOSS AS A PERCENTAGE OF NET OPERATING 

REVENUE (%) 0% 50% 16% 

5. OPERATING PROFIT MARGIN (%) 4% 2% 3% 

*Note that the measures in the tables below must be interpreted carefully. Operating costs do not include fixed costs 

and net revenue equals gross revenue minus operating costs.

TABLE 13. FLORIDA SOUTHWEST: ECONOMIC IMPACTS OF METHYL BROMIDE ALTERNATIVES

FLORIDA FRUIT & VEGETABLE 

ASSOCIATION – SOUTHWEST 

METHYL 

BROMIDE

Iodomethane GA – 3 WAY 

METHOD

PRODUCTION LOSS (%) 0% 0% 0% 

 PRODUCTION PER HECTARE (BOX 25LBS) 4,666 4,666 4,666 

* PRICE PER UNIT (US$) $ 11 $ 11 $ 11 

= GROSS REVENUE PER HECTARE (US$) $ 50,152 $ 50,152 $ 50,152 

- OPERATING COSTS PER HECTARE (US$)* $ 48,230 $ 49,197 $ 48,530 

= NET REVENUE PER HECTARE (US$) $ 1,922 $ 955 $ 1,622 

1. LOSS PER HECTARE (US$) $ - $ 967.11 $ 300.23 

2. LOSS PER KILOGRAM OF METHYL BROMIDE 

(US$) $ - $ 8.63 $ 2.68 

3. LOSS AS A PERCENTAGE OF GROSS REVENUE 

(%) 0% 2% 1% 

4. LOSS AS A PERCENTAGE OF NET OPERATING 

REVENUE (%) 0% 50% 16% 

5. OPERATING PROFIT MARGIN (%) 4% 2% 3% 

*Note that the measures in the tables below must be interpreted carefully. Operating costs do not include fixed costs 

and net revenue equals gross revenue minus operating costs.

USA CUN12 SOIL TOMATOES Open Field Page 16 of 27
TABLE 14. FLORIDA DADE: ECONOMIC IMPACTS OF METHYL BROMIDE ALTERNATIVES

FLORIDA FRUIT & VEGETABLE 

ASSOCIATION – DADE 

METHYL 

BROMIDE

Iodomethane METAM PLUS 

CHLOROPICRIN

PRODUCTION LOSS (%) 0% 0% 15% 

 PRODUCTION PER HECTARE (BOX 25LBS) 3,548 3,548 3,016 

* PRICE PER UNIT (US$) $ 10 $ 10 $ 10 

= GROSS REVENUE PER HECTARE (US$) $ 34,874 $ 34,874 $ 29,643 

- OPERATING COSTS PER HECTARE (US$)* $ 34,172 $ 34,665 $ 34,202 

= NET REVENUE PER HECTARE (US$) $ 702 $ 209 $ (4,559) 

1. LOSS PER HECTARE (US$) $ - $ 493 $ 5,261 

2. LOSS PER KILOGRAM OF METHYL BROMIDE 

(US$) $ - $ 3 $ 35 

3. LOSS AS A PERCENTAGE OF GROSS REVENUE 

(%) 0% 1% 15% 

4. LOSS AS A PERCENTAGE OF NET OPERATING 

REVENUE (%) 0% 70% 750% 

5. OPERATING PROFIT MARGIN (%) 2% 1% -15% 

*Note that the measures in the tables below must be interpreted carefully. Operating costs do not include fixed costs 

and net revenue equals gross revenue minus operating costs.

8. RESULTANT CHANGES TO REQUESTED EXEMPTION QUANTITIES 

The USG has applied an aggressive transition rate, which is reflected in the nomination amount 

and detailed in Table 15. 

TABLE 15. NOMINATION AMOUNT.

USA CUN12 SOIL TOMATOES Open Field Page 17 of 27
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Evaluation of various chemical treatment for potential as methyl bromide replacemnts for 

disinfetation of soilborne pests in polyethylene-mulched tomato. Proc. Fla. State Hort. 

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bromide plus chloropicrin doses under virtually impermeable films in pepper. Crop Prot. 

24: 285-287. 

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Combination with Herbicides on Purple Nutsedge (Cyperus rotundus) Control in Tomato. 

Weed Tech. 19: 101-104. 

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Fumigation and Pebulate Combinations in Tomato. Weed Tech. 19:575-579. 

Gilreath, J.P. B.M. Santos, J.D. Busacca, J.E. Eger Jr., J.M. Mirusso, P.R. Gilreath. 2006. 

Validation Broadcast Application of Telone C-35 Complemented with Chloropicrin and 

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Gilreath, J.P. B.M. Santos, T.M. Motis, J.W. Noling, and J.M. Mirusso. (2005) Methyl bromide 

alternatives for nematode and Cyperus control in bell pepper (Capsicum annuum). Crop 

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USA CUN12 SOIL TOMATOES Open Field Page 21 of 27
APPENDIX A 

Reproduced from the 2011 Critical Use Exemption Application submitted by the Georgia Fruit & 

Vegetable Association 

Summarized and Compiled by 

A. Stanley Culpepper, University of Georgia, Tifton 

1. Methyl Bromide Data Generated in Georgia 

Continued efforts are underway in Georgia to implement effective and economical alternatives to methyl 

bromide. During the spring of 2008, at least 40% of the land fumigated for vegetable crops in the spring 

was treated with the 3-WAY which includes a systems approach of 1,3-dichloropropene, chloropicrin, 

and metam sodium. It is likely that 30 to 40% of Georgia’s total crop will be treated with this alternative 

during 2008. Dimethyl disulfide (DMDS) plus chloropicrin also has proven to be effective in managing 

many pests and has the potential to be adopted once the price structure is known. 

Although both the 3-WAY and DMDS appear promising, neither fumigant system will stand alone in 

managing pests. A herbicide program must be developed to compliment these fumigant systems. The 3-

WAY does not provide adequate nutsedge control with summer/fall fumigations and the DMDS system 

does not adequately control grasses or Amaranthus species. Until program using fumigants and 

herbicides can be developed, having methyl bromide available is essential. 

The two aforementioned fumigant systems also pose significant challenges when determining the time 

interval needed between fumigating and planting. Initial research results suggest the plant back interval 

for the 3-WAY will be at least 3 times longer than that noted with methyl bromide (Item 3 below). For 

DMDS, the research is currently in progress with results available by September of 2008. Early 

indications suggest that the plant back for DMDS plus chloropicrin applied under a high barrier mulch 

will be similar to that noted with the 3-WAY system. 

Future research will focus on developing and implementing a herbicide program to compliment both the 

3-WAY and DMDS fumigant systems as well as determining the amount of time that must pass between 

fumigating with these alternatives and planting. 

USA CUN12 SOIL TOMATOES Open Field Page 22 of 27
2. A herbicide system must be developed for the UGA 3-WAY during summer/fall fumigation 

Introduction 

Georgia growers are adopting an effective alternative to methyl bromide during the spring fumigation 

cycle. However, research is needed to determine if this alternative is effective during the summer/fall 

fumigation period. Fumigants may be less effective in the summer/fall when compared to the spring 

because of warmer soils causing increased gas dissipation. 

Materials and Methods 

An experiment was conducted in TyTy Georgia at the University of Georiga’s Ponder Farm. The trial 

was conducted on a Tifton sandy loam soil with 92% sand, 2% silt, and 6% clay with a pH of 6.4 and 1% 

organic matter. Land was prepared by disking the trial area multiple times and then roto-tilling a 6 foot 

wide bed by 60 feet in length for each plot immediately prior to fumigating and installing mulch. 

The study was fumigated during the fall of 2007 on July 17. Soil temperature was 84 degrees at 8 inches. 

The experiment consisted of 4 treatments (Table 1) that were replicated three times. The UGA 3-WAY 

consisted of a system of Telone II (12 gal/A) followed by chloropicrin (150 lb/A) followed by Vapam (75 

gal/A). The Telone II was placed 12 inches deep using a Yetter system having 3 injection knives on a 32 

inch bed top, methyl bromide and chloropicrin were injected 8 inches deep with a super bedder using 3 

injection knives on a 32 inch bed top, and Vapam was injected 4 inches deep and 4 inches apart using disc 

blades in the final bed just prior to covering with mulch. Methyl bromide was applied at 240 lb/A. All 

fumigant rates are provided as broadcast rates but were actually only applied in the bed. Mulch used 

included low density polyethylene or Blockade high barrier mulch. 

Visual crop injury, visual weed control, and the number of nutsedge shoots penetrating the mulch were 

measured throughout the season. No visual injury was noted. Percent control and nutsedge penetrating 

the crop provided similar results thus only percent control is reported. Jumbo pepper was harvested four 

times, once a week for four weeks. 

Table 1. Comparing methyl bromide and the 3-Way for the control of nutsedge and tomato yield. 

Fumigant Mulch Late-season 

purple nutsdege 

control 

Harvests 1-2 

(Jumbo pepper) 

Harvests 1-4 

(Jumbo pepper) 

% # fruit/plot lbs/plot # fruit/plot lbs/plot 

3-WAY LDPE 48 d 34 c 16 c 44 c 19 c 

3-WAY Blockade 60 c 50 b 24 b 71b 32 b 

MB Blockade 85 b 106 a 48 a 136 a 61 a 

None LDPE 0 f 13 d 6 d 19 d 8 d 

Results and Discussion 

Poor nutsedge control was noted with the UGA 3-WAY system when applied under LDPE or Blockade 

mulch. Fumigant gas emissions occurred so rapidly that nutsedge tubers were likely not under a high 

enough concentration of gases long enough to provide adequate control as is the case in the spring. 

Methyl bromide was far more effective with nearly twice the level of control noted with the 3-WAY even 

under blockade mulch. As expected, yields followed trends in nutsedge control since it was the only pest 

impacting the crop. Yields from plots treated with methyl bromide were more than double that of the 

UGA 3-WAY applied under LDPE mulch. Although yield was improved with the 3-WAY applied under 

USA CUN12 SOIL TOMATOES Open Field Page 23 of 27
blockade mulch compared to LDPE mulch, this higher yield was only approximately half of that noted 

with the methyl bromide system. 

Conclusions 

The UGA 3-WAY is not a stand alone replacement to methyl bromide during a summer/fall fumigation in 

Georgia. Either an effective and economical herbicide system must be developed to compliment this 

alternative program or another more effective fumigant system must be developed. 

USA CUN12 SOIL TOMATOES Open Field Page 24 of 27
3. Determining plant back intervals when fumigating with the UGA 3-WAY 

Introduction 

The UGA 3-WAY system is replacing methyl bromide rapidly in Georgia. Although this system has been 

effective during the spring, the program has the potential to delay planting after fumigation. Research is 

needed to determine the time interval needed between fumigation and planting vegetable crops. 

 

Materials and Methods 

An experiment was conducted in Tifton Georgia at the University of Georgia’s Tifton Vegetable Park. 

The trial was conducted on a Tifton sandy loam soil with 94% sand, 2% silt, and 4% clay with a pH of 6.2 

and 1% organic matter. Land was prepared by disking the trial area multiple times and then roto-tilling a 

6 foot wide bed by 20 feet in length for each plot immediately prior to fumigating and installing mulch. 

The study was fumigated during the spring of 2007 on February 27. Soil temperature was 59 degrees at 8 

inches. The experiment consisted of 12 treatments (Table 1) that were replicated three times. The UGA 

3-WAY consisted of a system of Telone II (12 gal/A) followed by chloropicrin (150 lb/A) followed by 

Vapam (75 gal/A). The Telone II was placed 12 inches deep using a Yetter system having 3 injection 

knives on a 32 inch bed top, chloropicrin was placed 8 inches deep with a super bedder using 3 injection 

knives on a 32 inch bed top, and Vapam was injected 4 inches deep and 4 inches apart using disc blades 

in the final bed just prior to covering with mulch. Methyl bromide (MB) was included for comparison 

and was applied at 350 lb/A. All fumigant rates are provided as broadcast rates but were actually only 

applied in the bed. Mulch used included low density polyethylene or Blockade high barrier. Crops were 

planted 7 or 14 days after fumigating while poking the plant hole through the mulch. Crops were also 

planted on days 8 or 15 which was 1 day after poking the hole on days 7 and 14 in an attempt to air the 

bed. Crops planted included tomato, pepper and cucumber. 

Visual crop injury and crop heights (7 tomato, 20 pepper, 7 cucumber plants per plot) were measured 

throughout the season. Tomato, pepper and cucumber were harvested five, four, and nine times, 

respectively. 

Table 1. Plant heights in response to time of planting after fumigating. 

Fumigant Mulch Planting days 

after 

fumigation 

Gas in bed 

at planting 

Heights (cm) 

(3 wk after planting) 

ppm Tomato Pepper Cucumber 

MB LDPE 7 29 38 a 21 ab 30 ab 

3-WAY LDPE 7 77 32 cd 17 d 24 d 

3-WAY Blockade 7 368 14 f 4 f 12 f 

MB LDPE 7 + 1 2 37 ab 20 abc 32 a 

3-WAY LDPE 7 + 1 13 33 cd 18 cd 26 cd 

3-WAY Blockade 7 + 1 31 27 e 11 e 20 e 

MB LDPE 14 2 37 ab 22 a 32 a 

3-WAY LDPE 14 4 34 bc 20 abc 31 ab 

3-WAY Blockade 14 38 30 de 18 cd 28 bc 

USA CUN12 SOIL TOMATOES Open Field Page 25 of 27
MB LDPE 14 + 1 0 35 abc 22 a 31 ab 

3-WAY LDPE 14 + 1 3 33 cd 21 ab 31 ab 

3-WAY Blockade 14 + 1 27 30 de 19 bcd 28 bc 

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USA CUN12 SOIL TOMATOES Open Field Page 27 of 27

Table 2 . Plant yields in response to time of planting after fumigating. 

Fumigant Mulch Planting days 

after 

fumigation 

Gas in 

bed at 

planting 

Yield 

(#/plot, highest value fruit only; 

no difference noted with total 

fruit) 

ppm Tomato Pepper Cucumber 

MB LDPE 7 29 127 a 227 a 45 de 

3-WAY LDPE 7 77 127 a 195 ab 60 a 

3-WAY Blockade 7 368 55 c 114 c 40 e 

MB LDPE 7 + 1 2 117 a 212 a 47 cde 

3-WAY LDPE 7 + 1 13 132 a 193 ab 57 ab 

3-WAY Blockade 7 + 1 31 99 b 159 bc 47 cde 

MB LDPE 14 2 142 a 220 a 49 bcde 

3-WAY LDPE 14 4 132 a 190 ab 55 abc 

3-WAY Blockade 14 38 114 a 188 ab 49 bcde 

MB LDPE 14 + 1 0 133 a 204 ab 49 bcde 

3-WAY LDPE 14 + 1 3 127 a 202 ab 50 bcd 

3-WAY Blockade 14 + 1 27 119 a 190 ab 42 de 

Results and Discussion 

No visual stunting from methyl bromide was noted with any treatment at 3 wk after transplanting (data 

not shown). When planting 7 days after fumigating with the 3-WAY under LDPE mulch, crop heights 

were reduced at least 20% when compared to the methyl bromide control (Table 1). Growth reduction 

from the 3-WAY under Blockade mulch was far greater and ranged from 60 to 80%. Airing the bed for 

one day did not alleviate stunting. Waiting 14 days after fumigating before planting did alleviate 

fumigant stunting when crops were planted on the LDPE mulch. However, significant reduction in plant 

growth was still noted when planting into the blockade mulch. Airing the bed for 1 d did not eliminate 

crop stunting when planting on the blockade mulch. 

Tomato and cucumber were resilient in overcoming early season reduction in plant growth with only 

minor trends for reduced yields when planted on LDPE mulch, when compared to the methyl bromide 

control. Yield reductions were noted with tomato when planted on Blockade mulch at 7 or 8 d after 

fumigating. Pepper tended to be more sensitive than other crops with lower yields or a trend for lower 

yields when planting on both mulches at each planting date except for the 15 day plant date on LDPE 

mulch. 

Results and Discussion 

This research is the first step in determining the time interval needed between fumigating and planting. 

The most effective tactic will likely not be days after fumigating but ppm of fumigant in the bed at 

planting as the environment plays such a role in the dissipation of gas from the soil. This research 

suggests that for the UGA 3-WAY, less than 5 ppm should be in the bed at time of planting.