Four-Year Project to Address Grape Leafroll Associated Virus

Brian German Industry, Nuts & Grapes

A research project is underway looking to answer questions related to grape leafroll associated virus and its vector vine mealybug.  The ‘Refinement and Implementation of an Areawide Program for Vineyard Pathogens and their Insect Vectors’ project seeks to develop a practical strategy for addressing vine mealybug populations and determine the most cost-effective way for mitigating damage associated with leafroll disease.

grape leafroll associated virus

“The central theme of this is trying to use the control tools that we know work to stop the spread of grape leafroll associated virus,” said Kent Daane, Cooperative Extension Specialist with UC Berkeley and leader of the project. “One of the central themes within this is that you have got to test your vines. You have to determine how much of the vineyard block is infected and decide if it’s time to rogue those infected vines out and combine this with a mealybug control program.”

The research project, funded through the Biologically Integrated Farming Systems grant program, will be conducted in collaboration with growers in the Central Coast and Lodi regions. Addressing grape leafroll disease can be a costly endeavor and Daane hopes they will be able to answer several questions to improve the overall efficacy and cost of areawide treatment and suppression approaches.

“We need to understand where these infections are coming from,” Daane noted.  “Is it from the nurseries? Is it from mealybugs in the ground that are in the root remnants? Is it from mealybugs being blown in from next-door neighbors? Until we control the source of the infection, we cannot economically constantly rogue if we’re roguing every single year.”

Many growers have noted that once infected vines have been rogued, other infected vines will be discovered the following year.  The goal of the project is to develop a workable solution for growers dealing with infected vines. “We’re never going to eradicate the mealybug; we’re never going to control it to a zero population. So, if we can remove the pathogen from those blocks than its easier to tolerate a little bit of mealybugs for the winegrape grower,” Daane explained.

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Brian German

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Multimedia Journalist for AgNet West