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European Grapevine Moth Updated Info for SJValley

Submitted By: Lewis Perdue, April 01, 2011
News Submitted by San Joaquin Valley Winegrowers Association

European Grapevine Moth Updated Info

Growers in the new revised core area (reduced from 1000 meters to 500 meters) are strongly encouraged to spray first generation EGVM, in order to ensure there are no further finds of EGVM in the quarantine zone. With no further finds, the quarantine is expected to be lifted by the end of 2011. According to the University at least two sprays are needed to cover this prolonged emergence of adults from diapause. Emergence may begin as early as the first week in April and continue through the end of May. Adult moths that emerge are not strong flyers and will lay eggs on grape flower buds, and olive flowers in this first generation.

A total 37 Day-degrees have been accumulated so far this year since March 15th in the Del Rey area. Since there really is nothing for moths to lay eggs on, or larvae to feed on if eggs were to hatch, we are probab

ly early for a bio-fix. Based on historical temperatures we will arrive close to 100 day-degrees the first week in April. Since we have not and do not want to catch any EGVM moths, we will be estimating as to when moths will begin to fly (bio-fix). If there are pupa that overwintered from last year, they will be emerging this spring and most likely be caught in the more extensive trapping program this year.

The University recommendation for EGVM treatment for the first generation spray timings is April 15th through 21st for the first application with another followed three weeks later. The second application should be applied from May 5th through the May 12th. With both treatments the first generation will be covered. Long residual ovicide/larvacide materials like Intrepid or Altacor should be the first choice based upon efficacy and cost. These materials need to be applied prior to egg-laying to be most effective. Always follow all label restrictions.

There is a University of California approved list of materials for EGVM on the UC website link: Two new additions to that list will include Kryocide/ Cryolite and agri-mek that have been shown to control EGVM. Growers should be able to able to mix these materials in with their normal fungicide or insecticide spray programs. If growers need advice on materials to use and timing, they should consult their pest control advisor (PCA), the University of California, or the EGVM coordinator for choices of materials and timing.

Olive flowers are a primary EGVM host during this first generation, but the fruit is not infested by EGVM. Olive trees in the core area have been targeted for bloom time applications.

Tree fruit is a secondary host for EGVM. Growers in the quarantine area are still required to show they have an EGVM control program, so recommended EGVM sprays need to be applied in infested areas sometime in the first generation. Growers can also target other pest such as PTB, OLR or OFM and incorporate this in an early May spray that will control EGVM.

Table grapes (and wine grapes harvested as fresh) in the quarantine area will have the same restrictions as last year, an EGVM IPM program, traps and inspections every 14 days during harvest plus compliance agreements.

Thank you to Ken Schneider, EGVM treatment coordinator for this timely information