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NOMINATING PARTY: The United States of America

DATE: MARCH 27, 2013

FILE NAME: USA CUE15 DATES

BRIEF DESCRIPTIVE TITLE: U.S. Response to MBTOC February 14, 2013 Questions on 

Dates

SITE NAME (OPEN FIELD): Dates 

NOMINATING PARTY CONTACT DETAILS:

Contact Person: Federico San Martini, Ph.D.

Title: Foreign Affairs Officer

Address: Office of Environmental Policy

U.S. Department of State

2201 C Street, N.W. Room 2657

Washington, D.C. 20520 U.S.A.

Telephone: (202) 647-3819

Fax: (202) 647-1052

E-mail: SanMartiniFM@state.gov

CONTACT OR EXPERT(S) FOR FURTHER TECHNICAL DETAILS:

Contact/Expert Person: Mark Hartman

Title: Acting 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) 308-0734

Fax: (703) 308-7042

E-mail: Hartman.Mark@epa.gov

BACKGROUND

The United States government nomination is for 310 kilograms of methyl bromide to fumigate

freshly harvested dates. These dates are marketed for immediate consumption within 3 to 5 days 

of harvest (not held in storage). The eggs of dried fruit beetle and carob moth may be present at 

harvest, and only methyl bromide can kill these eggs within 24 hours.

Questions concerning moisture content of dates:

Information concerning the moisture content of dates, and also how to stabilize it, is key to the 

quality of dates during a fumigation, and of the choice of a fumigant. Understanding the moisture 
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content of dates leads to an understanding of the true restriction to fumigation with phosphine. 

That is why we really need to understand it thoroughly. 

MBTOC Question 1a. What is the range and the maximum Equilibrium Relative Humidity 

(e.r.h) or moisture content (m.c.) acceptable at harvest intake? Does e.r.h or m.c. vary over the 

harvest period and if so what are the contributing factors to this variation? 

U.S. Reply

“Fresh” Deglet Noor and Medjoul varieties grown in the Coachella Valley CA have a lower 

moisture content at harvest , 17-23% , relative to the same varieties grown in Algeria and 

Tunisia, which have a 35-40% moisture content (Ciesla et al, 2009). Dates in California 

ripen on the tree (i.e., we harvest at the mature tamar stage of the date), which results in a 

lower moisture content, higher sugars and less tannins than if the fruit is artificially ripened. 

Other countries may harvest dates at the khalal stage and then freeze or expose the dates to 

acetaldehyde/ethanol to ripen the fruit. 

Harvest in the Coachella Valley begins initially in more northern plantations and transitions 

toward the south, mainly due to the composition of the soil and cooler climate, over the 

course of mid-October to early-December. Dates harvested outside this period are not sold 

as fresh market dates (i.e, with a moisture content of 17-23%) but are stored, dried, and 

fumigated with phosphine (not methyl bromide). The U.S. critical use nomination for dates 

is only for those dates harvested between mid-October through early-December that are sold 

as fresh market dates (for immediate consumption). Fresh market dates account for 

approximately 30% of the California date harvest.

MBTOC Question 1b. Aerating the freshly harvested dates to even out differences in moisture 

content would avoid fumigation and allow phosphine to be used (with its longer treatment time). 

Do the dates ever have to be artificially dried to make them dry enough for ambient air storage? 

U.S. Reply

Dates are frequently dried to make them suitable for ambient air storage. Those dates are 

fumigated with phosphine, not methyl bromide. The U.S. critical use nomination is not for 

dates that are dried but only for freshly harvested dates, i.e., dates that are sold with a

moisture content between 17-23% and sent to the market in 3-5 days. 

Immediately after harvest, all incoming field bins of dates are fumigated in chambers, 

predominately with sulfuryl fluoride, to disinfest field pests. Key field pests include the 

carob moth and the dried fruit beetle and their eggs, which sulfuryl fluoride does not 

completely control with the labeled dose and/or exposure maximums within a treatment 

period of less than 3 days. Methyl bromide fumigation, which provides complete control of 

all life stages of carob moth and dried fruit beetle with a 24-h treatment, is used to disinfest 

shipments of “fresh” CA dates (17-23% moisture) that must be expedited to domestic 

markets. Dates from Coachella Valley CA that are not processed and shipped immediately 

after harvest (October – March) must be dried for storage. Stored dates are fumigated with 

phosphine in “stacks” of bins. As orders are filled throughout the year, stored dates are 
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rehydrated to 20% moisture content, processed, and distributed to market. Those dates are 

not treated with methyl bromide, but with sulfuryl fluoride.

Questions concerning comparative volumes of product to be MB treated:

MBTOC Question 2. EPA proposed rule (Federal Register, 77 FR 74435, December 14, 2012) 

describes the Limiting Critical Conditions for methyl bromide use in 2013. These conditions 

report, among other things, that MB use for dates is only for California dates in Riverside 

County. We are wondering if it is this Limiting Critical Condition which explains the variance 

we see in data on total date harvest.

U.S. Reply

MBTOC is correct: the United States critical use nomination is only for California dates 

grown in Riverside County. The nomination represents roughly one-third of the total 

production from Riverside County, which is the amount of freshly harvested dates that are 

rapidly fumigated and shipped for immediate consumption.

MBTOC Question 3. For example, the CUN (Table 4) reports total date harvest of 19,396 

tonnes. But, recently released data by USDA-NASS gives 2012 California production as 31,100 

tons (28,213 MT). Please provide the total harvest of dates for the entire State and/or county that 

is included in this CUN.

To assist you to understand the reasoning for this request, the CUN requests MB for 15,500 m3 

of dates, which MBTOC has to convert to tonnes and then determine the percentage of the total 

date harvest for which MB treatment is requested. 

U.S. Reply

The production figure in the CUN, 19,396 MT (21,380 short tons), is based on a five-year 

average of NASS data for total production of dates in the state of California from 2006-2010. 

EPA generally averages production and price data so that policy decisions are not based on 

information from an atypical year. For more detail see Table 1. 

MBTOC Question 4a. Converting dates from m3 to tonnage requires knowledge of the date 

storage bins and the stowage factors. The CUN requests MB for 15,500 cu m of dates. At this 

point, MBTOC has estimated 400kg of dates in the storage boxes (assumed 1 m3 capacity) and 

assuming 'under tarp' fumigation. With a 20% allowance for extra fumigated space for stacking 

and dunnage, 15,500 m3 of dates, as handled, is equivalent to about 5000 tonnes of dates. 

Sources in California can supply more accurate figures and if so, we would appreciate receiving 

them. 

U.S. Reply

Based on USG calculations, 15,500 cubic meters of dates would be equivalent to 8,276 

metric tonnes of dates. The calculations are as follows:
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15,500 cu m ÷ 1.2 (space allowance) = 12,917 cu m dates = 456,148 cu ft = 18,245,911 lbs1

= 9,123 short tons = 8,276 metric tonnes

The value of 15,500 cubic meters (8,276 metric tonnes) was nominated based on historic 

acreage for dates and, in order to account for natural variability in yield, a high potential 

yield. Table 1 shows dates production, bearing acres, and yield for the years 2000-2012. As 

acreage and production have increased, the U.S. nomination has decreased.

Dates production (i.e., yield per acre) varies each year based on the age of the trees and 

environmental conditions (rain, temperature), so the amount of fumigant needed in a given 

year will vary. However, the amount nominated is based on production acreage around the 

time of the first nomination. Table 1 shows the bearing acreage, yield per acre, total 

production, and the U.S. nomination for methyl bromide. To avoid market disruption, the 

U.S. nomination allows for slightly less than one-third of maximum yield of historic bearing 

acreage to be fumigated. The U.S. nomination for dates has decreased substantially, with the 

2015 nomination representing an almost 90% reduction from our initial nomination. 

Table 1. Dates: Acreage, Yield, Production, and US Nomination, 2000-2012

Year Bearing 

Acreage1

Yield

(tons/acre)

Production

(1,000 tons)

MeBr CUN 

(kg)2

2000 4800 3.63 17.4

2001 4900 4.02 19.7

2002 4800 5.04 24.2

2003 5200 3.46 18.0

2004 5500 3.13 17.2

2005 5700 3.02 17.2

2006 5500 3.22 17.7 3,016

2007 5300 3.08 16.3 3,016

2008 5700 3.67 20.9 2,009

2009 6700 3.54 23.7 2,009

2010 7700 3.77 29.0 2,009

2011 8400 3.96 33.3 2,009

2012 8400 3.70 31.1 1,063

2013 361

2014 325

2015 310

1 Acreage based on the USDA NASS survey, not the five-year census. The 2007 

agriculture census indicated there were also 1,600 acres of dates in Arizona. 

2

Sulfuryl Flouride (Profume) commercial introduction in the United States in April 

2004, for cereal grain, dried fruit, and tree nuts. Federal label amended to include other 

commodities, such as coffee beans, cocoa beans, rice flour, etc. on July 15, 

2005. California approved the initial label in June of 2005 and the amended label in the 

summer of 2006. The earliest these label changes would be reflected for California use 

 

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The value is calculated using a conversion factor of 40 lbs per cubic foot based on estimate submitted by dates 

growers and http://www.aqua-calc.com/calculate/food-weight-to-volume. 
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would be for the 2008 critical use nomination.

Sources: USDA NASS, Noncitrus Fruits and Nuts Summaries; USG Critical Use Nominations

MBTOC Question 4b. We believe the plastic boxes used for field storage of California dates 

may allow for more weight per cu m than does the wooden boxes used for other dried fruit in 

California, but seek confirmation of this.

U.S. Reply

Calculations would be based on the density of the fruit and not on the size or weight capacity 

of the fumigation bin. Dates have an average density of approximately 40 lbs per cubic foot. 

Even if the boxes used in California were larger or could hold more weight, the weight per 

cubic meter of the fruit would be the same, and the 20% space allowance would be 

proportionately the same. 

Questions concerning the impact of market timing on fumigation needs:

The CUN notes, ‘Commodity fumigation with methyl bromide is used primarily at harvest time, 

when rapid fumigation is needed to keep up with the large volumes of incoming commodities 

that need to be shipped to market in three days for maximum value.’

MBTOC Question 5. By this statement does the US actually mean that some portion of the 

harvest has to be quickly fumigated to get their crop to market within three days to achieve 

premium prices? When does the need for rapid marketing occur?

We ask this because other sources do not indicate a need for immediate marketing of dates, or a 

short market window. 

We are basing our statement on the following sources:

“Harvest Season: October 1 – December 15. This is reported in California Agricultural 

Statistics 2011 Crop Year. Issued by USDA National Agricultural Statistics Service, California 

Field Office, October 31, 2012. USDA-NASS also reported the following in 2006 for California 

dates:

Usual Harvesting Dates

Begins August 15

Most Active October 1 - December 15

Ends March 1

Usual Marketing Dates

Begins August 15

Most Active October 1 - December 20

Ends March 15

Source: Fruits and Tree Nuts: Blooming, Harvesting, and Marketing Dates, Agriculture, 

Handbook Number 729. USDA, National Agricultural Statistics Service. December 2006. 
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Marketing Year: October 1 through September 30 of the following year. This is established by 

the California Date Commission Law and is consistent with Federal Marketing Order 987: 

California Dates.”

Therefore we ask for more detailed substantiation of this CUN statement, since it forms a key 

basis for the CUN.

U.S. Reply

The United States nomination is for "fresh" dates shipped to market for immediate 

consumption by those consumers who prefer freshly harvested dates. The purpose is to meet 

consumer demand for fresh dates, not to obtain a higher price. Prices received for dates may 

vary based on fresh or processed or by time of year, but the economic analysis was based on 

average annual price per ton for all dates from USDA, National Agricultural Statistics 

Service (see Table 1). 

Questions concerning treatment parameters:

MBTOC Question 6. Is fumigation with MB restricted to a particular time of year and/or 

variety?

U.S. Reply

Methyl bromide fumigation of “fresh” dates for immediate consumption takes place between 

mid-October and early-December. There are no regulatory restrictions on the time of year or 

variety. 

MBTOC Question 7. What is the availability of, and size of, fixed fumigation structures?

U.S. Reply

The United States government does not have this information for the entire date industry. 

We do know that one production facility has duplicate chambers (3500 cu ft) each having a 

40 short ton capacity at normal atmospheric pressures and temperatures. This facility 

processes and fumigates approximately one third of the California date crop.

MBTOC Question 8. CUN notes that phosphine treatment takes longer than sulfuryl fluoride to 

fumigate dates (5 to 7 days), and during this time the dates ferment, resulting in an off-flavor and 

an unmarketable product. MBTOC needs to know the moisture content of the dates because it 

seems possible that the aspect of this statement pertaining to potential damage done by longer 

fumigation is incorrect. 

U.S. Reply

The United States nomination is for the freshly harvested dates going promptly (i.e., within 

3-5 days) into the marketplace for immediate consumption. Only stored dates are fumigated 

with phosphine in “stacks” of bins. Dates must be dehydrated in preparation for storage, as 

they ferment if stored with harvest-time moisture content of 17-23%. Phosphine fumigation 
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is not used to disinfest incoming bins of field pests when the moisture content of the dates is 

17-23% because treatment time required for efficacy against the target pests is too long. 

Sulfuryl fluoride’s reduced performance on the eggs of dried fruit beetle and carob moth,

which may be present on the dates, necessitates the use of methyl bromide for the rapid 

fumigation of the “fresh” dates. 

Questions concerning current and planned research on pest control for dates:

MBTOC Question 9. The CUN provides a bit of an indication of the planned research on MB 

alternatives for dates. However, we believe the CUN was written several months ago. At this 

time is it possible for the US to provide an update and more detail on the research being 

conducted this year and planned for next year on MB alternatives for dates?

U.S. Reply

Please refer to attached proposal, “Circumventing ovicidal deficiencies of sulfuryl fluoride 

and other postharvest fumigants: Optimization and technology transfer of the SF-PPO 

mixture.” The research will complete normal atmospheric pressure testing and then scale 

vacuum and normal atmospheric pressure fumigation toward commercial scale applications 

with validation for dates as well as walnuts. Research on the SF-PPO is ongoing (See 

Appendix 1).

Questions on fact checking - economics:

MBTOC Question #10. The table on page 4 of the CUN indicates a gross revenue of >US$32 

million per tonne. This seems unlikely. We note that the ‘Non-citrus Fruits and Nuts 2012 

Preliminary Summary (January 2013). USDA’s National Agricultural Statistics Service’ reports 

a 2011 price per tonne as US$1320 and a 2012 price per tonne of US$1340. Could the US please 

provide a correct number? 

U.S. Reply

MBTOC is correct that the $32 million refers to total value of production, not value per 

tonne. MBTOC is referencing the correct source for the numbers that were used in 

calculating the values. The values were calculated as an average from USDA NASS data 

over the five-year period from 2006-2010.

REFERENCES

Ciesla, Y. P. Ducom, C. Reichmuth, S. Walse. 2009. Harvest and disinfestation of Deglet Noor 

dates in the Coachella Valley (California), USA Company-guided visit of the Hadley 

Date Gardens with John Davies (Expert), and Albert P. Keck (President) 13 November 

2009. Report for MBTOC. 

USDA. 2013. National Agricultural Statistics Service. Noncitrus Fruits and Nuts Summary. 

2006-2013. Accessed online on March 1, 2013 at https://www.nass.usda.gov. 
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Walse, S. 2013. Circumventing ovicidal deficiencies of sulfuryl fluoride and other postharvest 

fumigants: Optimization and technology transfer of the SF-PPO mixture. See Appendix 

1. 
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Appendix 1.

USDA-ARS

San Joaquin Valley Agricultural

Sciences Center

PROJECT PLAN/RESEARCH

GRANT PROPOSAL

Project Year 2013 Anticipated Duration of

Project: 1 year

Project Leader Spencer S. Walse Location: USDA-ARS-SJVASC,

Parlier, CA Cooperating Personnel: J. Steven

Tebbets

Project Title: Circumventing ovicidal deficiencies of sulfuryl fluoride

and other postharvest fumigants: Optimization and technology transfer of the

SF-PPO mixture

Keywords

Commodity(s) walnuts, fumigation, Profume®, food security, propylene oxide,

microscopy

Relevant Project No. NA

Problem and its Significance:

Methyl bromide (MB) Critical Use Exemptions for postharvest applications are

being dissolved by MBTOC; an expiration date of 2015 has been proposed. The

dried fruit and nut industry of CA uses sulfuryl fluoride (SF) in scenarios

where disinfestations of insects are required within hours of harvesting.

However, the ovicidal deficiencies of SF toward several insect species endemic

to CA cast serious doubt on its technical merit, economic feasibility, and 

regulatory compliance when used in this capacity. Moreover, the USEPA has

proposed to revoke the SF label for use on foodstuffs, including walnuts,

with no clear resolution yet forthcoming.

The first year of the project expanded on the work of DFA of CA (Hurley &

Muhareb)by including tests on different insect species (NOW & CdM) and refining

the toxic mixture; SF was paired with propylene oxide (PPO), a potent ovicide,

to significantly reduce (~6-fold) the applied dose of SF required for adequate

kill of all life stages of the target pests. In addition, we were able to

comparatively evaluate using microscopy the egg physiology of stored product

insect pests including, dried fruit beetle, codling moth, indianmeal moth, and

navel orangeworm. The second year of the project focused on optimizing the

toxic SF- PPO mixture under vacuum and normal atmospheric pressures, as well

as evaluating the egg physiology of stored product insect pests including,

dried fruit beetle, codling moth, indianmeal moth, and navel orangeworm. In

addition, we were able to quantify the antimicrobial activity of the SF-PPO

mixture relative to MB, phosphine, and sulfuryl fluoride alone.
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The completion of this project will carry the SF-PPO mixture through commercial

validation and will yield the most effective MB alternative to date, with

the benefit of both insecticidal and anti-microbial efficacy.

Long-term goal: Ensure pest-free security and food safety of walnuts in

postharvest marketing channels via the development of efficient, economical,

and environmentally benign chemical treatments.

Short-term goal: Complete normal atmospheric pressure testing and then scale

vacuum and normal atmospheric pressure fumigation toward commercial scale

applications with validation.

Objectives:

1) Conduct insecticidal efficacy trials at Temperature < 70F (i.e., 50 &

60F).

2) Begin scaling fumigations toward commercial scenarios.

3) Determine the environmental factors (e.g., temp, air flushes, etc.)

that minimize chemical residues associated with ovicide-SF pairings,

particularly those resulting from the PPO-SF mixture. Tailor fumigantovicide application to minimize residue formation. 

4) Develop novel chemical and physical approaches to kill insect eggs

based on an understanding of egg biochemistry and/or the logistical

operations of walnut harvest and distribution.

Plans and Procedures:

Objective 1. At 70F, the optimized ratio for the SF-PPO mixture has been

identified under vacuum as well as normal atmospheric pressure. We will

follow the same experimental procedure and process at 50 and 60F.

Objective 2. At 70F, efficacy studies will transition from 1 cubic foot

chambers into nine cubic foot chambers and commodity will be included in the

testing.

Objective 3. To facilitate the detection of biomolecular conjugates,

mass-labeled propylene oxide will be synthesized via the method of Beckman. 

The mass-labeled PPO will then be used to fumigate inshell walnuts; a mass

balance will be generated. Mass-labeled residues that are likely to be

formed during walnut fumigations will be characterized in studies on

surrogate biomolecules such as: oleic acid, bovine serum albumen, and 

glutathione.

Objective 4. We will then expose eggs to fumigants, ovicides, and other

physiologically active gases to observe any morphological change that

results. Once mechanistic details are gathered, we will tailor chemical and

physical approaches to exploit weakness in egg shells. Approaches will only

be explored that are amenable to existing infrastructure of the walnut

industry.