USA CUN11 SOIL Sweet Potato Slips Open Field Page 1 of 11



### NOMINATING PARTY: The United States of America

FILE NAME: USA CUN11 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 2009 for 2011 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


### 2011 14,515 kilograms

NOMINATING PARTY CONTACT DETAILS: Contact Person: Hodayah Finman Title: Foreign Affairs Officer 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) 647-1123 Fax: (202) 647-5947

E-mail: finmanhh@state.gov

Following the requirements of Decision IX/6 paragra ph (a)(1) The United States of America has determin ed that the specific use detailed in this Critical Use Nominati on is critical because the lack of availability of methyl bromide for

this use would result in a significant market disru ption. 

## ■ Yes  No

Signature Name Date

Title:

(Details on this page are requested under Decision Ex. I/4(7), for posting on the Ozone Secretariat w ebsite under Decision Ex. I/4(8).)

This form is to be used by holders of single-year e xemptions to reapply for a subsequent year’s exempt ion (for example, a Party holding a single-year exemption fo r 2005 and/or 2006 seeking further exemptions for 2 007). It does not replace the format for requesting a critic al-use exemption for the first time.

In assessing nominations submitted in this format, TEAP and MBTOC will also refer to the original nomi nation 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 Pa rty need not re-submit that earlier information.USA CUN11 SOIL Sweet Potato Slips Open Field Page 2 of 11



### CONTACT OR EXPERT(S) FOR FURTHER TECHNICAL DETAILS:
Contact/Expert Person: Jack E. Housenger Title: Director, Acting 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 CUN11 SOIL SWEET POATO SLIPS Open Field

2. ELECTRONIC COPIES OF ALL PAPER DOCUMENTS: *Title of each electronic file (for naming conventi on see notes above) No. of kilobytes Date sent to Ozone

Secretariat USA CUN11 SOIL SWEET POTATO SLIPS Open Field

* Identical to paper documentsUSA CUN11 SOIL Sweet Potato Slips Open Field Page 3 of 11



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

SWEET POTATO SLIPS

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

Sweet potato production in California has two disti nct production components: transplant production and field production. This cultural req uirement is similar to many other crops, e.g. strawberries, vineyards, and orchards, but for swee t potatoes the production of transplants and harvested roots is done by the same grower. Transp lant and field production both utilize fumigation when possible, however, greater weed and disease control is required in the transplant nursery. This requirement is currently being met by using methyl bromide flat fumigation with plastic tarp. Field production uti lizes low rate (12 to 15 gallons per acre) of 1,3- dichloropropene without tarping to control nematode s. Field production of sweet potatoes in California is concentrated in a relatively small ge ographic area in the central part of the state, and

because of this exceeds the current use allotment o f 1,3-dichlropropene allowed within a township (640 acres). Growers cannot use 1,3-dichr lopropene in January and the township cap restrictions on 1,3-dichlropropene require an appli cation factor of 1.9 in December, and the cap being exceeded in November (Cal DPR, 2002). Thus t he choice of fumigants available to growers for the transplant production is limited by state regulations, 1,3-dichlropropene is essentially unavailable for use in the fall when fu migation occurs. Thus, growers use methyl bromide + chloropicrin combinations for the transpl ant production (nursery) areas.

This request is for the sweet potato transplant pro duction area only, where plant production of sweet potato slips occurs. These areas are usually fumigated from November through January. Transplants are grown between February – May, and t he cuttings (slips) from the transplant production area are transplanted between late April 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 th at are transplanted between late April and early June. The majority of sweet potato roots are harve sted in September and October.

2. SUMMARISE WHY KEY ALTERNATIVES ARE NOT FEASIBLE:

This request is only for those growers who cannot u se 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 market window. In addition, those growers who fumigate in November do not have 1, 3-dichloroprope ne available because the township cap has been exceeded by other crops that fumigate earlier in the year (see Trout 2005). The combination of 1, 3-dichlropropeme plus chloropicri n is highly rated for control of nematodes, certain diseases and some weed species. This is ba sed upon years of grower experiences on other crops using the respective ingredients alone and in combinations. Prior to the delabeling of 1, 3-dichloropropene by Cal DPR in the early 1990’s , tarped 1,3-dichloropropene + chloropicrin was the main fumigation choice for the sweet potato nursery area. This combination would alsoUSA CUN11 SOIL Sweet Potato Slips Open Field Page 4 of 11



### be the preferred drop-in replacement for MeBr if it were no longer available and 1,3- dichloropropene restrictions were not in place. R esearch results from the first year of a three year study are described in part 7 below.

California growers produce their transplants (slips ) for propagation in open fields and initially cover plants with clear plastic row covers supporte d by hoops. Prior to being used for transplant production, fields are either fallowed or planted t o rye or sweet potatoes the previous season. The transplants (slips) must be watered during esta blishment and the low rainfall amounts and public water restrictions that exist in the product ion areas make it imperative that fields are situated near private irrigation wells, which signi ficantly limits the land available for growing transplants.

Growers of sweet potato slips face a difficult situ ation with the township caps because all of the fumigated areas fall within just four townships in Merced County. Merced county has already exceeded a 2x cap allowance, so growers have alread y reverted to the lower 1,3 -dichloropropene use limit. Additional evidence that the 1,3 -dichl oropropene cap will be exceeded in 2011 is that in 2002, the California Department of Pesticide Reg ulation (CDPR) gave a special allowance to one of the Merced county townships, where sweet pot ato was the primary 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 t hese sweet potato slips are grown.

There are over 5,000 hectares (> 12,500 acres) acre s in sweet potato production, 53 ha (131acres) of plant beds of which are fumigated with methyl br omide, and 1987 ha (4908 acres), open field treated with 1,3-D. When the banked allowance is e xpended 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 allowed for 316,554 pounds of 1,3-dichloropropene while there was demand for 583,807 pounds.

3. IS THE USE COVERED BY A CERTIFICATION STANDARD?

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

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 W HAT ALTERNATIVE STRATEGIES ARE USED TO

CONTROL THE TARGET PATHOGENS AND WEEDS W ITHOUT METHYL

BROMIDE THERE.

Organic sweet potato growers do not use methyl brom ide, or any other fumigants, in their transplant beds. It has been observed that fewer a nd less vigorous transplants result. Since data are not available to address these options, the ext ent of these differences cannot be quantified. In addition, in order to produce their crops, organic producers of sweet potatoes must use significant amounts of hand weeding. Current costs are not available.USA CUN11 SOIL Sweet Potato Slips Open Field Page 5 of 11



### 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?

The 1, 3- dichloropropene township cap limitation e ffectively limits the amount of 1, 3- dichloropropene that can be used on a sliding scale . This scale is a function of amount, method of fumigation, and time of year. To the extent tha t 1, 3- dichloropropene or a 1, 3- dichloropropene plus chloropicrin mixture can be us ed, it is being used. California growers prefer to use 1, 3- dichloropropene when possible ( 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- dichloropropene township caps and regulations. Solarization is undergoing evaluation, however, it is not likely that solarization can completely replace fumigation. Solarization can only take pla ce during the same time period as cropping (the non-cropping season is not warm enough to allo w soils to reach the temperatures necessary to kill key pests to the required soil depths.

6. SUMMARY OF RECENT RESEARCH:

Scott Stoddard presented data from the first year o f 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 seco nd year has begun by implementing the fumigation treatments with data collection in 2009. 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 (Table 7) the only alternatives that would provide adequate p est control and crop safety also contain 1,3- dichloropropene (Telone) whose label restrictions a nd townships caps are already a constraint on its use. There were no significant differences bet ween treatments for Pythium sp. control (number of colony forming units) or root rotting. The methyl bromide: chloropicrin treatment had the fewest weeds. Weed control was improved wh en napropamide or Valor were added. 1,3-dichloropropene plus metam sodium and Valor cau sed some phytotoxicity but did not lead to significant yield reduction.

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. Devrin ol (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.USA CUN11 SOIL Sweet Potato Slips Open Field Page 6 of 11

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.



### F IGURE 

### 1. S WEET 

### P OTATO 

### S LIPS 

### ( PLANTS PER 

### 4 SQUARE FEET 

### )

Source: Stoddard, 2008 MBAO.USA CUN11 SOIL Sweet Potato Slips Open Field Page 7 of 11

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.



### 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.USA CUN11 SOIL Sweet Potato Slips Open Field Page 8 of 11



### 7. ECONOMIC FEASIBILITY OF ALTERNATIVES

Please note that in this study net revenue is calcu lated as gross revenue minus operating costs. This is a good measure as to the direct losses of i ncome 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 for an ente rprise, is gross revenue minus the sum of operating and fixed costs. Net income is smaller t han the net revenue measured in this study, often substantially so. We did not include fixed c osts because they are difficult to measure and verify.

The economic reviewers analyzed crop budgets for pr e-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 isola tion.

(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 measure, at least over some unit, e.g. , a hectare of land or a storage operation. However, high value commodities or crop s may provide high revenues but may also entail high costs. Losses of even a small percenta ge 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 goo d 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 oper ating 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 en terprise. Again, operating costs may be

difficult to measure and fixed costs even more diff icult, therefore fixed costs were not included in the analysis.

These measures represent different ways to assess t he economic feasibility of methyl bromide alternatives for methyl bromide users, who are swee t potato slip 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 me t if there is a significant impact on commodity suppliers using methyl bromide. The economic measu res provide the basis for making that

determination.USA CUN11 SOIL Sweet Potato Slips Open Field Page 9 of 11



### Slips are produced for the sole purpose of transpla nting into the open fields by growers and they are not sold commercially. Therefore, slip product ion is an input process to sweet potato production, with its associated costs. Thus, the y ield loss of the final product, sweet potato, is the relevant yield loss that may result from the us e of alternative to methyl bromide. Methyl bromide is used to fumigate hot beds for slip produ ction. One acre of hot beds typically produces enough slips for transplanting into about 60 field acres to produce sweet potato.

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 use d because of the township caps, and solarization only partially controls pathogens. Th us, chloropicrin is analyzed as the next best alternative to methyl bromide. Table 6 indicates t hat use of chloropicrin results in an 11% increase in production over methyl bromide. Hand w eeding costs are greater with chloropicrin (Table 6), but overall, production increase outweig hs the cost increases and results in positive economic impacts as shown in Table 6.

T ABLE 6. 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 Research Progress Report 2005

.



### Table 6 summarizes economic impacts of using chloro picrin. Yield increases by 11% with a gain of $1,410/hectare with the use of chloropicrin . This gain is 7% and 22% of the gross revenue and net operating revenue, respectively.USA CUN11 SOIL Sweet Potato Slips Open Field Page 10 of 11



### 8. RESULTANT CHANGES TO REQUESTED EXEMPTION QUANTI TIES

T ABLE 

### 7: N OMINATION 

### A MOUNT



### . 2011 Methyl Bromide Usage Newer Numerical Index (BUNNI) – Transition Use Reduction Description Spreadsheet

.

Sweet Potato

Council of

California Sector Total /

Average

Quantity Requested for 2010: Amount (kgs) 18,144 18,144

Quantity Recommended by

MBTOC/TEAP for 2010 : Amount (kgs) 14,515 14,515

Amount (kgs) 14,515

14,515

Area (ha) 81

81

Rate 179 179

Transition from 2010 Baseline Adjusted Value Percentage (%) -20% 0%

Amount (kgs) 

## 14,515

14,515

Area (ha) 

### 81

81

Rate 

### 180 180 SECTOR SWEET POTATO SLIPS

Quantity Approved by Parties

for 2010:



### Quantity Required for

2011 Nomination:USA CUN11 SOIL Sweet Potato Slips Open Field Page 11 of 11



### CITATIONS

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

CDFA (California Department of Food and Agriculture ). 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 Progres s Report 2005. UCCE Merced County. Provided by C.S. Stoddard.

Stoddard, C.S. 2008. Research Progress Report: Fu migation and cover crop trial on sweet potatoes. University of California Cooperative Ext ension Service, Merced County.

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

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