### NOMINATING PARTY: The United States of America

FILE NAME: USA CUN12 S OIL 

### S WEET 

### P OTATO 

### S LIPS 

### O PEN 

### F IELD



### BRIEF DESCRIPTIVE TITLE OF NOMINATION: Methyl Bromide Critical Use Nomination for Preplant Soil Use for Sweet Potato Slips Grown in Open Fields (Submitted in 2010 for 2012 Use Season)

CROP NAME: Sweet Potato Slips Open Fields

QUANTITY OF METHYL BROMIDE REQUESTED:

T ABLE 1. Q UANTITY OF M ETHYL B ROMIDE R EQUESTED IN E ACH Y EAR OF N OMINATION



### Y EAR 

### N OMINATION 

### A MOUNT



### 2012 8,709kg

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 critic al 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 exem ption for 2005 and/or 2 006 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.

USA CUN12 SOIL Sweet Potato Slips Open Field Page 1 of 15

### CONTACT OR EXPERT(S) FOR FURTHER TECHNICAL DETAILS:
Contact/Expert Person: Jack E. 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: jack.housenger@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 SWEET POATO SLIPS Open Field 11

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 SWEET POTATO SLIPS Open Field

* Identical to paper documents

USA CUN12 SOIL Sweet Potato Slips Open Field Page 2 of 15

## METHYL BROMIDE CRITICAL USE RENOMINATION FOR PREPLANT SOIL USE (OPEN FIELD OR PROTECTED ENVIRONMENT)

SWEET POTATO SLIPS

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

Sweet potato production in California has two distinct production co mponents: transplant production and field production. Th is cultural requirement is similar to many other crops, e.g. strawberries, vineyards, and orchards, but for sweet potatoes the producti on of transplants and harvested roots is done by the same grower. Transplant and fiel d production both utilize fumigation when possible, however, greater we ed and disease contro l is required in the transplant nursery. This requirement is curr ently being met by using methyl bromide flat fumigation with plastic tarp. Fi eld production utilizes low rate ( 12 to 15 gallons per acre) of 1,3- dichloropropene without tarping to control nematodes. Field production of sweet potatoes in

California is concentrated in a rela tively small geographic area in th e central part of the state, and because of this exceeds the current use allotment of 1,3-dichlropropene allowed within a township (640 acres). Growers cannot use 1,3-di chrlopropene in January and the township cap restrictions on 1,3-dichlropropene require an application factor of 1.9 in December, and the cap being exceeded in November (Cal DPR, 2002). Thus the choice of fumigants available to growers for the transplant pr oduction is limited by state regu lations, 1,3-dichlropropene is essentially unavailable for use in the fall when fumigation occurs. Thus, growers use methyl bromide + chloropicrin combinations for th e transplant producti on (nursery) areas.

This request is for the sweet potato transplant production area only, where plant production of sweet potato slips occurs. These areas are usua lly fumigated from November through January. Transplants are grown between February – May, and the cuttings (slips) from the transplant production area are transplanted between late Apr il and early June. The majority of sweet potato roots are harvested in September and October. The total area Sweet potatoes are transplanted from plant propagules , called slips that are transplanted between late April and early June. The majority of sweet potato roots are harvested in September and October.

The USG has reviewed all factor s affecting transition rates in this sector. Based on this assessment the transition rate has been greatly incr eased 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 nomi nated amounts of methyl bromide based only on those sub-sectors that cannot transition away from methyl bromide at the accelerated rate.

2. SUMMARISE WHY KEY ALTERNAT IVES ARE NOT FEASIBLE:

This request is only for those growers who cannot use 1,3-dichloropropene due to regulatory constraints. Fumigation with 1, 3-dichloropropene is prohibited in California during December and January. The soil where sweet potato “slips” (transplants) is typically fumigated from November through January in order to meet a ma rket window. In addition, those growers who fumigate in November do not have 1, 3-dichloro propene available because the township cap has been exceeded by other crops that fumigate earlier in the year (see Trout 2005). The

USA CUN12 SOIL Sweet Potato Slips Open Field Page 3 of 15

### combination of 1, 3-dichlropropeme plus chloropicr in is highly rated for control of nematodes, certain diseases and some weed species. This is based upon years of grower experiences on other crops using the respective i ngredients alone and in combinati ons. Prior to the delabeling of 1, 3-dichloropropene by Cal DPR in the early 19 90’s, tarped 1,3-dichloro propene + chloropicrin was the main fumigation choice for the sweet potato nursery area. This combination would also be the preferred drop-in replacement for methyl bromide if it were no longer available and 1,3- dichloropropene restrictions were not in place. Research results from the first year of a three year study are described in part 7 below.

California growers produce their tr ansplants (slips) for propagation in open fields and initially cover plants with clear plastic row covers supported by hoops. Prior to being used for transplant production, fields are either fallo wed or planted to rye or swee t potatoes the previous season. The transplants (slips) must be watered during establishment and the low rainfall amounts and public water restrictions that exist in the production areas make it imperative that fields are situated near private irrigation wells, which significantly limits the land available for growing transplants.

Growers of sweet potato slips face a difficult situation with the township caps because all of the fumigated areas fall within just four townships in Merced County. Me rced county has already exceeded a 2x cap allowance, so growers have al ready reverted to the lower 1,3 -dichloropropene use limit. Additional evidence that the 1,3 -dichl oropropene cap will be exceeded in 2012 is that in 2002, the California Department of Pesticide Re gulation (CDPR) gave a special allowance to one of the Merced county townships, where sw eet potato was the primar y fumigant use, to exceed their cap by 16,500 adjusted pounds. Similar allowances have been given several times

since 2002.

Iodomethane is not registered in California, where these sweet potato slips are grown.

There are over 5,000 hectares (> 12,500 acres) acres in sweet pot ato production, 53 ha (131acres) of plant beds of which are fumigated with me thyl bromide, and 1987 ha (4908 acres), open field treated with 1,3-D. When the banked allowan ce is expended this will leave 2,227 acres (or 44%) that cannot use 1,3 -dichloropropene that otherwise would have. In 2003, for example, the cap (without any bank) only allo wed for 316,554 pounds of 1,3-dichloropropene while there was demand for 583,807 pounds.

The USG has reviewed all factor s affecting transition rates in this sector. Based on this assessment the transition rate has been greatly incr eased 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 nomi nated amounts of methyl bromide based only on those sub-sectors that cannot transition away from methyl bromide at the accelerated rate.

3. IS THE USE COVERED BY A CERTIFICATION STANDARD?

Methyl bromide is not used to meet a certific ation standard for sweet potato slip production.

USA CUN12 SOIL Sweet Potato Slips Open Field Page 4 of 15

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

INDICATE THE REASON WH Y METHYL BROMIDE IS NOT USED IN THE OTHER AREA, AND IDENTIFY WHAT ALTER NATIVE STRATEGIES ARE USED TO

CONTROL THE TARGET PATHOGENS AND WEEDS WITHOUT METHYL

BROMIDE THERE.

Organic sweet potato growers do not use methyl bromide, or any other fumigants, in their transplant beds. It has been observed that fewer and less vigorous transpla nts result. Since data

are not available to address these options, the extent of these diffe rences cannot be quantified. In addition, in order to produce their crops, or ganic producers of sweet potatoes must use significant amounts of hand weeding. Current costs are not available.

5. WOULD IT BE FEASIBLE TO EXPAND THE USE OF THESE METHODS TO

COVER AT LEAST PART OF THE CRO P THAT HAS REQUESTED USE OF

METHYL BROMIDE? WHAT CHANGES WOULD BE NECESSARY TO ENABLE

THIS?

The 1, 3- dichloropropene township cap limitati on effectively limits the amount of 1, 3- dichloropropene that can be used on a sliding sc ale. This scale is a function of amount, method of fumigation, and time of year. To the exte nt that 1, 3- dichlo ropropene or a 1, 3- dichloropropene plus chloropicrin mixture can be used, it is being us ed. California growers prefer to use 1, 3- dichloropropene when possibl e (where the key pests are controlled and where the township caps are not binding) as it is less co stly than mixtures using methyl bromide. The US nomination is for growers who will be denied the use of 1, 3- dichloropropene alone or in combination with chloropicrin as a result of 1, 3- dichloropropen e township caps and regulations. Solarization is undergoing evaluation, however, it is not likely that sola rization can completely replace fumigation. Solarization can only take place during the same time period as cropping (the non-cropping season is not warm enough to a llow soils to reach the temperatures necessary to kill key pests to the required soil depths.

The USG has reviewed all factor s affecting transition rates in this sector. Based on this assessment the transition rate has been greatly incr eased 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 nomi nated amounts of methyl bromide based only on those sub-sectors that cannot transition away from methyl bromide at the accelerated rate.

6. SUMMARY OF RECENT RESEARCH:

Scott Stoddard presented data from the first year of a three year study at the Methyl Bromide Alternatives Outreach conference (Stoddard, 2008) . In his email (Oct. 28, 2008) Scott Stoddard indicated that the first year is complete; the second year has begun by implementing the fumigation treatments with data collection in 20 09. He plans on continuing the project for three years with a completion in the fall of 2010. In hi s summary of the first years research the only alternatives that would provide adequate pest control and cr op safety also contain 1,3- dichloropropene (Telone) whose label restrictions and townships caps are already a constraint on its use. There were no significant differences between treatments for Pythium sp. control (number of colony forming units) or root rotting. The methyl br omide: chloropicrin treatment

USA CUN12 SOIL Sweet Potato Slips Open Field Page 5 of 15

### had the fewest weeds. Weed control was improved when napropamide or Valor were added. 1,3-dichloropropene plus metam sodium and Valor caused some phytotoxicity but did not lead to significant yield reduction. We have also presented additional interim data on the second year of the three year study.

T ABLE 2. S WEET P OTATO S LIP R ESEARCH IN C ALIFORNIA

– Y EAR 1 OF 3 Y EAR S TUDY

M AIN P LOTS S PLIT P LOTS 1. Methyl Bromide + Chloropicrin (53:47) at 350 lbs/acre tarped. 1. Untreated

2. Chloropicrin at 150 lbs/acre, tarped 2. Devrinol (napropamide) 4 lbs/acre 3. PicChlor 60 (60% Chloropicrin & 40% 1,3-D ) at 45 gal/acre, tarped 3. Valor (flumioxazin)at 2 oz/acre

4. Solarization 4. Botran (dichloran) at 3.5 lbs/1000 sq ft 5. Telone (1, 3- dichloropropene) 20 gal/acre + Vapam (metam sodium) 75 gal/acre 5. Mertec (thiabendazole) at 30 oz/1000 sq ft

6. Untreated control
Source: Stoddard, 2008 MBAO.

Treatments Application Dates Solarization June 26, 2007 MeBr:Pic, Chloropicrin, & PicChlor August 20, 2007 Telone & Vapam November 12, 2007 Botran & Mertec February 28, 2008 at planting Devrinol & Valor March 7, 2008

Film – Std LDPE 1.5 mil

T ABLE 3. S WEET P OTATO S LIP P LANT P RODUCTION IN 2008

S LIP T REATMENT P LANTS PER 4 SQUARE FEET 1. MeBr + Chloropicrin 160 bc 2. Chloropicrin 155 b

3. PicChlor 120 cd

4. Solarization 110 d 5. Telone & Vapam 160 b

6. Untreated control 230 a
Source: Stoddard, 2008 MBAO.

USA CUN12 SOIL Sweet Potato Slips Open Field Page 6 of 15

### F IGURE 

### 1. S WEET 

### P OTATO 

### S LIPS 

### ( PLANTS PER 

### 4 SQUARE FEET 

### )

Source: Stoddard, 2008 MBAO.

T ABLE 4. S WEET P OTATO C ROP P RODUCTION FROM T REATED S LIPS IN 2008

S LIP T REATMENT LBS / ACRE OF ROOTS
1. MeBr + Pic 65,000 c 2. Chloropicrin 72,000 ab

3. PicChlor 67,000 bc

4. Solarization 69,000 bc 5. Telone & Vapam 78,000 a

6. Untreated control 57,000 d
Source: Stoddard, 2008 MBAO.

USA CUN12 SOIL Sweet Potato Slips Open Field Page 7 of 15

### F IGURE 

### 2. S WEET 

### P OTATO 

### R OOT 

### Y IELD 

### ( POUNDS PER ACRE 

### )

Source: Stoddard, 2008 MBAO.

T ABLE 5. S UMMARY OF S WEET P OTATO S LIP T RIAL TO D ATE

T REATMENT W EED
C ONTROL P LANT
P RODUCTION F UMIGATION
C OST H AND
W EEDING R EGULATION
I SSUES 1. MeBr:chloropicrin A A $ 2100 100 Phase out 2. Chloropicrin BC A $ 1900 400 VOC

3. PicChlor A B $ 2100 100 VOC, Caps

4. Solarization C C $ 1200 600

--- 5. Telone + Vapam AB A $ 500 100 VOC, Caps

6. Untreated control C A 0 600

--- Source: Stoddard, 2008 MBAO.



### 2008 -2009 Methyl bromide fumigation alternatives for sweetpotato hotbeds in California. Project Period: June 2008 – December 2009 (2nd fumigation cycle/year) A cooperative research project between UC Cooperative Extension and USDA-ARS Report Preparer: Scott Stoddar d, UC Cooperative Extension

2145 Wardrobe Ave Merced, CA 95341

USA CUN12 SOIL Sweet Potato Slips Open Field Page 8 of 15

### MeBr, Pic alone, Pic Chlor 60, and solarization treat ments (main plots) were installed on July 15, 2008, using the services of Tri Cal, Inc. Plastic tarp used was 1.25 mil, standard PE plastic with UV inhibitors. Plots were 140 ft long by 25 ft wide, and were replicated three times using a randomized split-block design. Soil temperature probes were installed on the same day. Plastic and probes were removed on September 16, 2008. On December 11, 2008, the Telone + Vapam treatment were applied by Tri Cal using “rotova te and roll” equipment. Because of crop phytotoxicity concerns from year one with this treatment, rates were reduced to 15 gpa Telone and 40 gpa Vapam.

On March 9, 2009, the grower coope rator installed hotbeds into th e treated areas. Hotbeds were 8 ft wide by 85 ft long, and centered within each fumigated treatment area. Split plot treatments were imposed with the application of fungicides (Botran and Mertect) to the sweetpotato roots prior tocovering with soil. On March 16, 2009, pr e-emergent herbicides Devrinol and Valor were also applied as separate split plot treatments to each bed within the main plot fumigation area. All fungicide and herbicide treatments were made using a hand boom attached to a backpack sprayer.

On April 9 and 17, 2009, weeds were evaluated in each split plot. On April 9, visible weeds per plot (100 sq ft) were counted a nd classified: on April 17th hand weeding times were measure for the plots. Hand weeding was conducted by using grower cooperator labor.

On May 7, 2009, a field day was held to view and di scuss the treatments in the trial. About 15 people attended. Nematode and disease sampli ng also took place on this day. For both, the upper 6 inches of soil beneath th e sweetpotato roots was sampled using a standard soil probe. Inoculum density of Pythium spp. was determined by soil dilution plating onto a semiselective agar (corn meal agar amended with pimaricin a nd antibiotics). All the colonies of Pythium on the plates were enumerated. Each assay was done in triplicate.

Plant stand counts were made on May 15 by randomly tossing a 2 x 2 ft square into the center of each split plot and cutting at the soil line all sprouts within this area. 50 plant cutting from this selection were also transplanted in a produc tion field on May 19, 2009. The purpose of the field transplanting is to determine whether fumigation choice has an impact on the yield potential of the harvested root (for example, weak diseased plants would result in reduced yields as compared to healthy vigorous plants).

Results Soil temperature data at 1, 3, 6, and 12 inches under bard ground (UTC) and the solarization treatment from July 15 to September 15, 2008, are shown in Figures 1 and 2. The clear plastic tarp used in this trial signifi cant increased soil temps at all depths. At one inch, temps exceeded 125 oF with plastic, 109 oF without.

Nematodes were sampled by taking a 500 cc soil sa mple from each of the main plot (MeBR + Pic, Pic alone, Pic Chlor 60, Tel one + Pic, Solarization, UTC) trea tments in February before the beds were installed and again at plant harves t in May. No root knot nematodes (Meloidogyne incognita) or other plant parasitic nematodes we re found at either sampling event (Table 1).

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### The soil analysis for potential root rotting path ogens showed no significant differences among treatments. Pythium populations were extrem ely low in all plots (in general, Pythium populations in most soils in the San Joaqui n Valley average between 20 and 50 dfu/g).

Weed pressure was not that high in this area, pr obably because it had been previously fumigated with MeBr. However, there were significant diff erences between the main plot treatments, with greatest number of weeds in the untreated *UTC) and solarization treatments. These treatments also required the most hand weeding time, av eraging 25 and 20 seconds per man per 100 ft2. Significant differences were also noted between the split plot trea tments for weed control. Application of either herbicide significantly reduced weed pressure as compared to not treating, with Valor having the greatest efficacy on the we eds present at this lo cation (puncture vine, malva, pigweed, mustard, barnyard grass). However, Valor caused some noticeable crop phytotoxicity with a corresponding reduction in plant production. Even with this, plant production was excellent in 2009, with 240 to 280 plants per 4 ft2 (much better than 2008 production). No crop phytotoxicity was seen between the fumigation treatments.

Table 6. Nematode, Pythium, weed counts, and plant production from the 2 nd year of the trial (2009).

Nematodes (RKN/100g) Nonparasitic Pythium Weeds #/plot Crop Phyto Weed

Time Plant

counts
Treatment 11 – Feb 7-May 7-May Cfu/g

soil 9-Apr 9-Apr Sec/ man/ plot #/4 sq

ft

1 UTC 0 0 200 3.2 47.4 1.2 25 235

2 MeBr + Pic, 350

lbs/A 0 0 94 2.1 4.4 1.2 8 268

3 PicChlor 60, 45 gpa 0 0 111 2.5 13.4 0.6 16 254

4 Vapam 40 gpa + Telone 12 gpa 0 0 134 0.5 5.6 1.6 9 306

5 Pic only, 150 lb/A 0 0 135 3.0 16.4 1.6 14 258

6 Flat solarization 0 0 190 1.8 22.4 2.0 20 264

P value Ns Ns ns 0.75 ns 0.001 0.25 ns 0.07 0.79 ns

LSD 0.05

--- 15.1

--- 12

--- CV 147.3 68.4 102 65.6 16.3

1 UTC 32.2 0 Not weeded 278

2 Devrinol (napropamide) 4 lb/A 11.9 0.6 15 281

3 Valor (flumioxazin) 1.5 oz/A 0.7 4.3 6 242

4 Botran (dichloran) 3.5 lbs/1000 sq ft/10 gals 27.3 0.4 20 268

5 Mertect (thiabendazole) 30 fl oz/1000 sq ft/10 gals 33.4 0.6 25 274

6 Devrinol + Valor tank mix 4.0 2.2 9 244

P value 0.001 0.001 0.001 0.02

LSD 0.05 8.3 0.9 6.6 28.7

CV 68.4 102 65.6 16.3

P value, Main Plot x Split plot

Interaction ND ND ND ND 0.001 0.91 ns 0.65 ns 0.47 ns

Footnote: Nematodes and Pythium were determined within main plot treatments only.

USA CUN12 SOIL Sweet Potato Slips Open Field Page 10 of 15Weed counts a re a combination of broadleaf, grass, an d yellow Nutsedge. Broadleaf spp include puncture vine, malva, pigweed, and mustard.



### 7. ECONOMIC FEASIBILITY OF ALTERNATIVES

Please 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

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### indicates profitability of an operation for an enterprise, is gross revenue minus the sum of operating and fixed costs. Net income is smalle r than the net revenue measured in this study, often substantially so. We did not include fixe d costs because they are difficult to measure and verify.

The economic reviewers analyzed crop budgets fo r pre-plant sectors to determine the likely economic impact if methyl bromide were unavailab le. 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.

(3) Loss as a Percentage of Gross Revenue. This measure has the advantage that gross revenues are usually easy to meas ure, at least over some unit, e.g. , a hectare of land or a storage operation. However, high value commodities or cr ops may provide high revenues but may also entail high costs. Losses of even a small per centage 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 ma rgin 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 di fficult, therefore fixed costs were not included in the analysis.

These measures represent different ways to a ssess the economic feasibili ty of methyl bromide alternatives for methyl bromide users, who are sw eet potato slip producers in this case. Because producers (suppliers) represent an in tegral part of any definition of a market, we interpret the threshold of significant market di sruption 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.

Slips are produced for the sole purpose of transplanting into th e open fields by growers and they are not sold commercially. Therefore, slip pr oduction is an input process to sweet potato production, with its associated cost s. Thus, the yield loss of the final product, sweet potato, is the relevant yield loss that may re sult from the use of alternative to methyl bromide. Methyl bromide is used to fumigate hot beds for s lip production. One acre of hot beds typically produces enough slips for transplanting into ab out 60 field acres to produce sweet potato.

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### For hot bed fumigation, there are four alternatives to methyl bromide (Tables 4 and 5). Of these, Telone + Vapam (1,3-D + Metam-sodium) cannot be used because of the township caps, and solarization only partially controls pathogens. Thus, chloropicr in is analyzed as the next best alternative to methyl bromide. Table 6 indicate s that use of chloropicr in results in an 11% increase in production over methyl bromide. Ha nd weeding costs are greater with chloropicrin (Table 7), but overall, production increase outweighs the cost increases and results in positive economic impacts as shown in Table 7.

T ABLE 7. C ALIFORNIA S WEET P OTATO S LIPS

- E CONOMIC I MPACTS OF M ETHYL B ROMIDE
A LTERNATIVES

C ALIFORNIA S WEET P OTATO S LIPS M ETHYL B ROMIDE C HLOROPICRIN

Y IELD L OSS (%) 0 -11

Y IELD PER H ECTARE ( CWT / HECTARE ) 737 818

* P RICE PER U NIT (U.S.$) 28 28

= G ROSS R EVENUE PER H ECTARE (U.S.$) 20,632 22,902

- O PERATING C OSTS PER H ECTARE (U.S.$) 14,200 15,060

= N ET O PERATING R EVENUE PER H ECTARE (U.S.$) 6,432 7,841

1. L OSS PER H ECTARE (U.S.$) 0 -1,410

2. L OSS PER K ILOGRAM OF M ETHYL B ROMIDE (U.S.$) 0 -6

3. L OSS AS A P ERCENTAGE OF G ROSS R EVENUE (%) 0 -7

4. L OSS AS A P ERCENTAGE OF N ET O PERATING R EVENUE (%) 0 -22

Source: Sweet potato Resear ch Progress Report 2005.



### Table 7 summarizes economic impacts of using chloropicrin. Yield increases by 11% with a gain of $1,410/hectare with the us e of chloropicrin. This gain is 7% and 22% of the gross revenue and net operating revenue, respectively.

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### 8. RESULTANT CHANGES TO RE QUESTED EXEMPTION QUANTITIES

T ABLE 

### 8: N OMINATION 

### A MOUNT



### . 2012 Methyl Bromide Usage Newer Numerical

Sweet Potato

Council of

California Sector Total /
Average

Quantity Requested for 2011: Amount (kgs) 14,515 14,515

Quantity Recommended by

MBTOC/TEAP for 2011 : Amount (kgs) 11,612 11,612

Amount (kgs) 11,612 11,612

Area (ha) 81 81

Rate 179 143

Transition from 2011 Baseline Adjusted Value Percentage (%) -25% -25%

Amount (kgs) 

## 8,709 8,709

Area (ha) 

### 58 58

Rate 

### 150 150 Quantity Approved by Parties

for 2011:



### Quantity Required for

2012 Nomination: SECTOR SWEET POTATO SLIPS

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### CITATIONS

CDFA (California Department of Food and Agriculture). 2002. Recommended permit conditions for using 1,3-dichloropropene fu migants. September 12, 2002. Available online at http://www.cdpr.ca.gov/docs/enfcm pli/penfltrs/penf2002/2002atch/attach37.pdf

CDFA (California Department of Food and Agri culture). 2005. Notice of Proposed and Final Decisions and Directors Findings . December 2005. Available online at http://www.cdpr.ca.gov/docs/nod/2005-50.htm

Stoddard, C.S. 2005. Sweetpotato Research Pr ogress Report 2005. UCCE Merced County. Provided by C.S. Stoddard.

Stoddard, C.S. 2008. Research Progress Report: Fum igation and cover crop trial on sweet potatoes. University of California Coope rative Extension Service, Merced County.

Stoddard, C.S. 2008. MeBr Alternatives for Sweet Potato Hotbeds in California. Available online at: http://www.mba o.org/2008/027Stoddard.pdf

Trout, T. 2005. Impact of township caps on telo ne use in California. Annual International Research Conference on Methyl Bromide A lternatives and Emissions Reductions, 2005. http://www.mbao.org/2005/05Proceedings/ 127TroutT%20mb-pest-use-telone-rpt05- mbao.pdf