BIOLOGY AND MANAGEMENT OF MEALYBUGS IN WASHINGTON WINE GRAPE VINEYARDS

• Sponsoring Institution: State Agricultural Experiment Station
• Project Status: COMPLETE
• Funding Source: STATE
• Reporting Frequency: Annual
• Accession No.: 0189650
• Project Start Date: Jul 1, 2001
• Project End Date: Jul 1, 2004
• Program Code: [(N/A)]- (N/A)

Recipient Organization
WASHINGTON STATE UNIVERSITY
240 FRENCH ADMINISTRATION BLDG
PULLMAN,WA 99164-0001

Performing Department
PROSSER IRRIGATED AG RESEARCH AND EXTENSION CENTER

Non Technical Summary
Development and registration of pest control chemistries that would serve as alternate treatments for chlorpyriphos is extremely important to the wine grape industry in Washington State. Results will be transferred to users through submission of reports to the Washington grape growing organization, Extension Bulletins, and presentation given at fieldman/grower meetings, Washington Association of Wine Grape Growers and Washington Wine Grape Society annual meetings plus invited talks and seminars.

Animal Health Component

(N/A)

Research Effort Categories

Basic

100%

Applied

(N/A)

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
212	1131	1130	100%

Knowledge Area
212 - Pathogens and Nematodes Affecting Plants;

Subject Of Investigation
1131 - Wine grapes;

Field Of Science
1130 - Entomology and acarology;

Keywords

disease management

wine

grapes

pseudococcus maritimus

leaf roll

chlorpyrifos

pseudococcidae

plant disease control

insect biology

insect control

regional research

species composition

spatial distribution

disease transmission

performance evaluation

optimization

application timing

natural enemies

environmental impact

chemical control (insects)

non target organisms

food composition

infection

food quality

insect identification

insect collection

monitoring

Goals / Objectives
1. Determine which species of mealybug are prevalent in Washington State wine grape vineyards, their relative abundance and distribution: 2. Determine the ability of grape mealybug to transmit Grapevine leafroll associated viruses: 3. Conduct research on optimum timing and effectiveness of candidate compounds for grape mealybug control and their impact on natural enemies of the grape mealybug. 4. Determine the effect of grapevine leafroll disease on mineral composition of the grape cluster rachis, and the impact of infection on berry quality.

Project Methods
Object 1. Samples of mealybug will be collected from vineyards throughout south central Washington, preserved and forwarded to appropriate specialists for species identification. Sampling and monitoring will also be conducted to provide information on the abundance of mealybugs and leafroll disease in selected vineyards. Object 2. Grapes vines will be selected that are suspected of being affected by grapevine leafroll disease. Mealybugs located on these vines will be identified to the species level, collected and transferred to disease-free, greenhouse grown vine. The nymphs will be enclosed in gauze sleeves and allowed to remain on recipient grapevines until late summer. The vines will be monitored over subsequent seasons for the development of symptoms. Leaf petioles will be tested by molecular means to verify visual diagnoses. An equal number of vines will have no nymphs added to the sleeve and these will be the negative control vines. Object 3. a. Delayed-dormant insecticide application. We propose to establish a spray trial in a vineyard with a history of mealybug infestation. Chlorpyriphos in combination with a petroleum derived spray oil will be applied to serve as the commercial standard. b. In-season chemigation. We propose to test several systemic neonicotinyl insecticides for their ability to suppress mealybug infestation. Imidacloprid injected into the drip irrigation system in June will serve as our commercial standard. Candidate compounds that may be included are thiacloprid, thiamethoxam, and acetimiprid. c. Mealybug population abundance estimation. To determine the pre-treatment background level of mealybug infestation at out test sites, spur samples will be taken from each of the replicate plats in late-March. The spurs will be transported to the laboratory and the number of mealybug crawlers per spur will be counted. A second set of spurs will be taken and scanned at 5 days after insecticide application to determine the initial knockdown of each of the candidate compounds. Object 4. Two independent vineyards with a history of leafroll disease will be selected for study. Twenty vines will be identified in each vineyard: ten with leafroll disease and ten without. The disease status of the vines will be confirmed as will as the identity of the leafroll viruses on the basis of molecular test. Berry clusters will be collected from these vines at four times through the season, beginning at veraison, and continuing to commercial harvest date. Mineral status of the rachis will be measured. Comparison of diseased and disease-free vines in each vineyard will indicate which minerals, if any are affected by leafroll disease and at which stage of berry development at which the nutritional imbalance occurs. At commercial harvest date, clusters from diseased and disease-free will be collected and basic quality parameters measured and compared.

Progress 07/01/01 to 07/01/04

Outputs
This project has investigated the impact of mealybug feeding on wine grapes in Washington State. Mealybug feeding would have minimal effect on grape production, except for the fact that mealybugs vector grape vine leaf roll disease. GVLRD is lethal to grape in Washington State vineyards. This project has contributed to the registration of 3 effective insecticides that are highly effective at reducing or eliminating mealybug populations in vineyards. Two of the insecticides registered include the systemic neonicitinoids imidacloprid and thiamethoxam. This project has proven that both of these insecticides are most effective when they are applied via chemigation. The third insecticide registered is buprofezin. This insecticide is categorized by US-EPA as reduced risk. It is and insect growth regulating insecticide. All three of these insecticides are prefered and more effective alternatives to the orgganophosphate insecticide clorpyrihos that had been the control agent used befor the start of this project.

Impacts
This project has resulted in registering the insecticides buprofezin, imidacloprid, and thiamethoxam. The registration of thiamethoxam is pending. All of these products provide good economic control of mealybugs.

Publications

• No publications reported this period

Progress 01/01/02 to 12/31/02

Outputs
This project aided the registration of arthropod pest management tools for grape producers. Products registered for use on grapes in 2002 include buprofezin, fenpyroximate, fenpropathrin, and bifenthrin. All of these insecticide/miticide products are classified as reduced risk to humans and serve as good organophosphate insecticide replacements.

Impacts
New insecticides serve as replacements for disruptive organophosphate insecticides.

Publications

• No publications reported this period

Progress 01/01/01 to 12/31/01

Outputs
Progress has been made in understanding the biology of mealybugs in vineyards and research has begun to determine if GMB is a vector for grape vine leaf roll disease.

Impacts
This project is responsible for the Section 24C registration permitting the application of imidicloprid through drip irrigation. This could save grape producers millions of dollars in the future.

Publications

• Walsh, D., K. Eastwell, D. James, and W. Bentley. 2001. Mealybug on the rise in Washington State. 2001. Good Fruit Grower. 52(6)20-22.
• Walsh, D. 2001. Homoptera and Neonicotinyls. Imidacloprid Aids in GWSS Battle in California. Issue No. 186.
• Walsh, D. 2001. IR-4 Projects 2001 and 2002 (Insecticides and Herbicides). Issue No. 183.
• Walsh, D., K. Eastwell, D. James, and W. Bentley. 2001. Grape Mealybug. Issue No. 179