VIA EMAIL: dpr12001@cdpr.ca.gov

June 4, 2012

Linda Irokawa-Otani

Regulations Coordinator

Department of Pesticide Regulation

1001 I Street, P.O. Box 4015

Sacramento, California 95812-4015

RE: DPR 12- 001 Volatile Organic Compounds in the San Joaquin Valley Ozone Nonattainment Area 

Dear Ms. Irokawa-Otani:

On behalf of California Grape & Tree Fruit League, a nonprofit agricultural trade association representing 

fresh grape, berry, and deciduous tree fruit grown in California, I write to comment on the proposed 

action on nonfumigant use prohibitions on certain crops in the San Joaquin Valley ozone nonattainment 

area when using products with agricultural uses containing abamectin, chlorpyrifos, gibberellins, or 

oxyfluorfen during May 1 through October 31 if the volatile organic compound (VOC) emission limit is 

triggered. For fresh table grapes, growers need the flexibility to utilize an array of plant health materials 

to produce a marketable crop in the face of weather related challenges and pest pressures. The proposed 

action to limit the use of the liquid form of gibberellins will disrupt cultural practices employed by fresh 

grape growers in the San Joaquin Valley. As you may know, gibberellins have multiple beneficial uses in 

a table grape vineyard. For example, gibberellins are applied in a vineyard before bloom to stretch the 

berry cluster. The pre-bloom application creates a looser berry cluster, allowing for better air circulation 

which can reduce incidences of fungal disease. Gibberellins are also applied at bloom as a thinning spray 

to reduce the number of berries in a bunch, which serves to aid the growth and maturation of remaining 

berries. Following berry set, sizing sprays are applied to promote growth and development. Stretch, 

thinning, and sizing sprays directly contribute to proper growth and development by enhancing the 

architecture of the grape bunch to create spacing and sizing benefits while reducing the need to use 

additional fungicide materials to combat disease. The current proposal to limit use of liquid formulations 

to 8 grams AI/acre widely underestimates table grape needs for proper development.

The proposed limitation to 8 grams AI/acre for all table grape varieties overlooks variety specific cultural 

practices. According to the survey used to support the 8 grams AI/acre recommendation, Proposed 

Exemptions to San Joaquin Valley Ozone Nonattainment Area Use Restrictions, emphasis was placed on 

thinning and sizing “needs” for the varieties Ruby Seedless and Crimson Seedless, while all other 

varieties were combined under “Other.” Thinning application recommendations for use of gibberellins 

suggested rates as low as 0.5 to 1 grams AI/acre, and up to 16 grams AI/acre for sizing applications for 

Ruby Seedless as sufficient to ensure proper development and maturation. Of concern, the survey 

influenced the decision to set the exemption rate at 8 grams AI/acre; a rate which does not account for the 
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full range of gibberellins uses and use rates, within cultural practices for table grape production. Label 

language on gibberellins ranges from 8-24 grams AI/acre as a pre-bloom application, 0.5 grams AI/acre to 

20 grams AI/acre as a thinning application, and 20-128 grams AI/acre for sizing applications. 

Application rates of gibberellins vary depending on grape variety and growers are careful to calculate the 

amount requisite for optimal development and maturity knowing that both under and over application of 

gibberellins can delay development on color and sugar, negatively affect maturation, and/or reduce 

fruitfulness which can severely impact the marketability of the crop. The proposal’s potential impact is 

further compounded by the challenges that exist with measurement of non-liquid formulations, as 

conversion from liquid to power is not easily measurable. Table grape growers cannot supplant 

assumption for precision in identifying the requisite amount(s) for applications to support the 

development of a crop. The potential for altering gibberellins programs, under a proposal that woefully 

underestimates use rates required for stretch, thinning, and sizing sprays, is highly concerning given the 

devastating effects from restricting use of liquid gibberellins on table grapes to no more than 8 grams 

AI/acre, regardless of application purpose. Moreover, the proposal’s potential to affect cultural practices 

by restricting use away from liquid gibberellins also has the potential to increase labor costs if growers 

are left with fewer options and are forced to bear the added expense of manual thinning.

The need for nonfumigant use prohibitions in the San Joaquin Valley ozone nonattainment area when 

using products with agricultural uses containing abamectin, chlorpyrifos, gibberellins, or oxyfluorfen 

during May 1 through October 31 if the volatile organic compound (VOC) emission limit is triggered 

should be re-examined in light of the correction for bifenthrin VOC emissions, lowering the 2010 

emissions average from 16.8 to 15.5 tons per day, 24% less than the State Implementation Plan reduction 

goal of a 12% reduction from 1990 levels, or an 18.1 tons per day average. As a result of the adjustment, 

we ask DPR to re-consider the continued development of the current form of the draft regulation and 

engage affected stakeholders to incorporate greater flexibility for nonfumigant use. The current draft 

regulation should rectify the inability to remove an active ingredient as a regulated material, for purposes 

of the draft proposal, if use patterns demonstrate it no longer fits the selection criteria for top nonfumigant 

VOC contributor. If use patterns change resulting in a reduction in pesticide VOC emissions for a 

particular active ingredient it would not be fair to continue to apply use restrictions in light of updated 

data. 

Thank you for the comment opportunity. The scope of any such regulation should strive to be effective in 

reducing risk of reaching the trigger limit while only focusing on what is absolutely necessary to remain 

below the trigger. The California Grape & Tree Fruit League views this as an occasion to provide 

information to DPR to assist in the understanding of the benefits of important materials, such as 

gibberellins, and needs for optimal table grape development. Should you have additional questions please 

do not hesitate to contact me at the League by email (cvaladez@cgtfl.com) or by calling the League 

office.

Sincerely,

Christopher Valadez

Director, Environmental & Regulatory Affairs