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Dow AgroSciences LLC dowagro.com

9330 Zionsville Road Indianapolis, IN 46268 USA

7 December 2012

Linda Irokawa-Otani, Regulations Coordinator

California Department of Pesticide Regulation

1001 I Street, P.O. Box 4015

Sacramento, CA 95812-4015

dpr12001@cdpr.ca.gov

Re: Modifications to Text of Proposed Changes in the Regulations Pertaining to Volatile Organic

Compounds in the San Joaquin Valley Nonattainment Area.

Dear Mrs. Irokawa-Otani:

On behalf of Dow AgroSciences LLC, I am providing the following comments to DPR on the abovereferenced revision to the proposed amendment to the State Implementation Plan under the Clean Air

Act for the San Joaquin Valley Nonattainment Area.1

Dow AgroSciences appreciates and supports in concept the modification to the proposed VOC

regulations that provides an exception for use of high-VOC formulations of oxyfluorfen:

“6884. San Joaquin Valley Ozone Nonattainment Area Use Prohibitions.

(b) Notwithstanding (a), the following exceptions for use of high-VOC products are

permitted:

(3) Use of oxyfluorfen products when applied at an application rate of 0.125 (1/8)

pounds of active ingredient per acre or less.”

As mentioned in earlier comments from Dow AgroSciences and numerous industry stakeholders, the use

of high-VOC formulations of oxyfluorfen are necessary for successful postemergent control of weeds

during the summer months. However, Dow AgroSciences is concerned that the limitation of only 0.125

(1/8) pound of active ingredient would not provide consistent efficacy for the control of difficult weeds

such as Malva, morningglory, purslane, and late germinated sowthistle, particularly under a wide range

of soils, climate, irrigation practices, and weed pressure in the Central Valley. An analysis of the

California Pesticide Use Report for 2010 shows approximately 50% of post-emergent summer

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In addition to the comments in this letter, Dow AgroSciences incorporates by reference its previous

comments on the proposed regulation, submitted to DPR on June 7, 2012, and reserves all objections

then noted to the proposed regulation therein.
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applications of EC formulations of oxyfluorfen in Central Valley tree nuts were over 0.125 lbs ai/Ac (8

fl.oz./acre) (See Addendum 1, attached). Limiting the exemption to only 0.125 lb ai/acre would deprive

growers of needed postemergent and residual weed control. Raising the exclusion for EC formulations

of oxyfluorfen to a 0.25 lb ai/acre rate (1 pint/acre) in grapes and tree nuts would provide improved

efficacy, especially of hard to control weeds.

Sincerely,

Brian

Brian L. Bret, Ph.D.

Regulatory Manager

blbret@dow.com

cc: Randy Segawa, DPR Environmental Monitoring
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ADDENDUM 1.

OBJECTIVE - Determine if 0.125 lb ai/acre rate is consistent with California tree nut grower practices.

MATERIALS AND METHODS

CA DPR Pesticide Use Reporting database:

- Central Valley Counties - lbs chemical applied

- Almonds, pistachios, walnuts - Acres treated

- EC formulations of oxyfluorfen applied between May 1-October 31, 2010

Calculations:

- lbs/acre

- number and percent of applications < 0.125 lbs ai/acre

- number and percent of applications < 0.25 lbs ai/acre

RESULTS:

2010 PUR

By County

Lbs a.i.

applied MayOct

Acres

Treated

May-Oct

Lbs/acre

May-Oct

# apps.

< 0.125

lbs/A

% apps.

< 0.125

lbs/A

# apps

< 0.25

lbs/A

% apps.

< 0.25

lbs/A

Fresno 13,472.75 41,398.25 0.3254 254 43.42% 461 78.80%

Kern 25,955.72 107,427.42 0.2416 369 30.37% 775 63.79%

Kings 2,082.01 10,759.89 0.1935 76 54.68% 98 70.50%

Madera 8,324.72 42,963.28 0.1938 325 41.14% 686 86.84%

Merced 6,083.69 43,142.72 0.1410 726 66.24% 996 90.88%

San Joaquin 4,253.08 24,737.07 0.1719 378 49.09% 617 80.13%

Stanislaus 9,722.28 63,334.52 0.1535 993 57.97% 1,539 89.84%

Tulare 3,106.56 16,471.61 0.1886 171 53.44% 276 86.25%

Total 73,000.82 350,234.76 0.2084 3,292 49.67% 5,448 82.20%

 Over 50% of post-emergent summer apps of EC formulations of oxyfluorfen in Central Valley were

over 0.125 lbs ai/Ac (8 fl.oz./acre)

 Over 30% of applications were between 0.125-0.25 lbs ai/acre (8-16 fl.oz./acre)

 Up to 82% of applications were less than or equal to 0.25 lb ai/acre (16 fl. oz. or 1 pint) rate.

CONCLUSIONS:

A significant amount of EC oxyfluorfen use is above the 0.125 lb ai/acre rate exclusion.

Limiting exclusion to only 0.125 lb ai/acre (8 fl.oz.) would deprive growers of needed postemergent

and residual weed control for hard to control weeds.

Providing an exclusion for EC formulations of oxyfluorfen up to 0.25 lb ai/acre rate (16 fl.oz.) gives

better control and longer residual of hard to control weeds in tree nuts.