In 1996 Congress passed the Food Quality Protection Act (FQPA). FQPA replaced the “zero tolerance” standard of the Delaney Clause for pesticide residues in processed food with the standard of “reasonable certainty of no harm” which applies to all pesticides used on all foods. Under the FQPA, the Environmental Protection Agency will review all pesticide registrations for food crops under a three tier “priority” system, equivalent to high (I), medium (II), and low (III) risk categories.

The FQPA Grape Partnership, made up of wine, raisin, and table grape growers and organizations, federal and state regulators [US-EPA, California Environmental Protection Agency’s Department of Pesticide Regulation (DPR), California Department of Food and Agriculture], university researchers (SAREP, UC Statewide Integrated Pest Management Project, California Pesticide Impact Assessment Program), and environmentalists (Natural Resources Defense Council), was convened in 1998 by the California Association of Winegrape Growers (CAWG) and funded by US-EPA.

The major objectives of the partnership are to: 1) help satisfy US-EPA and USDA data needs for FQPA implementation; 2) generate crop-pest profiles for wine, raisin and table grapes, and to assist the grape industry in developing alternatives to FQPA Priority I and II pesticides; 3) identify critical research needs, demonstration needs, and field validation work on alternatives to FQPA Priority I and II pesticides; and 4) serve as a model pro-active approach to FQPA transition within the agriculture industry.

An executive summary as well as the 100-page winegrape pest profile is available on the CAWG web site at www.cawg.org. This review summarizes the key pests, non-chemical cultural and biological controls, Priority I (highest risk) FQPA pesticides used by the California winegrape industry, FQPA Priority II and III alternative chemicals, new alternative reduced-risk chemicals pending registration, and short and long term research priorities needed in light of implementation of FQPA.

Summary of Important Pests

1. Insect and Mite Pests. Grape vines are eaten by dozens of insect and mite species, but only about 12 species in six distinct pest categories [leafhoppers, spider mites, phylloxera, omnivorous leafrollers (OLR), sharpshooters and mealybugs] cause enough consistent and significant damage to be considered major pests in California. Of these, just three groups (leafhoppers, spider mites and OLR) are responsible for 85 percent of all insecticide/miticide chemical treatments on winegrapes.

2. Diseases. About two dozen diseases attack grapes, but only about 12 species in six distinct pest categories (powdery mildew, Botrytis and other bunch rots, Pierce’s disease, Phomopsis, Eutypa and other canker diseases and measles) cause enough consistent and significant damage to be considered major pests in California. The fungus powdery mildew alone is responsible for over 80 percent of all chemical treatments for diseases on grapes.

3. Nematodes. Five categories of nematodes (root knot, citrus, root lesion, ring and dagger) are responsible for most of the damage done to California grapevines. Root knot and ring nematodes are responsible for most of the chemical treatments for nematodes on grapes.

4. Weeds. Over two dozen species of weeds are commonly found in California vineyards, and they are a major pest throughout the state.

5. Vertebrate Pests. Vertebrate pests fall into four categories (birds, rodents, deer and coyotes). Overall, they are considered minor pests and receive few chemical treatments.

California Winegrape Pest Management System and the FQPA

The crop profile submitted to the USDA emphasizes the nine major grape pest categories which receive the majority of FQPA Priority I and II chemical treatments: weeds, powdery mildew, Botrytis bunch rot, spider mites, leafhoppers, OLR, mealybugs, nematodes and sharpshooters. Each of these pest categories has at least one FQPA Priority I or II material registered, none is completely dependent on these materials, and in the short term, six out of the nine pests can be effectively controlled using currently registered materials as substitutes. The three exceptions are late-season OLR, root knot nematode and mealybugs. In the long run, there are several alternative materials pending registration for powdery mildew and spider mites, and at least one for weeds, leafhoppers, sharpshooters, Botrytis, root knot nematode and OLR.

The pesticide use data in the profile is from DPR’s 1997 Pesticide Use Report. Cost estimates are based on expenses per acre per application, and are categorized as low (<$10/acre), medium ($15-30/acre), high ($35-45/acre) and very high (>$50/acre).

The following three tables summarize information in the 1999 winegrape pest profile.

Table 1 outlines three scenarios of possible future research priorities for the industry targeting key pests prioritized by: 1) the percentage of acreage treated with FQPA Priority I and II materials; 2) the number of effective, registered substitutes for FQPA Priority I and II materials; and 3) for comparison the 1997 American Vineyard Foundation (AVF) survey of priorities for research funding.

Table 2 details the important winegrape pests, registered chemicals broken out by FQPA priority status (Priority I vs. Priority II and III), and new alternative chemical controls pending registration. It includes the percentage of acreage treated with the currently registered material in 1997.

Table 3 outlines the same key winegrape pests and their current cultural, biological and other integrated pest management (IPM) practices, and a more detailed outline of possible short- (1-5 year time frame) and long- (5-10 years) term research priorities into alternative control methods for these pests.