Apr 26, 2012 | View All Issues
We continue to find mainly 1st instar GMB in vineyards we are monitoring from Pope Valley to Oak Knoll. We found all of our GMB under the bark of spurs and/or canes. We have not yet found GMB on the leaves, although we could expect to see them on the leaves with next week's warmer weather.
If you are planning to use an insect growth regulator (Applaud) to treat this overwintering generation of GMB, it will be important to make your applications while we still have young instars in the field (in the next couple of weeks).
According to Lucia Varela, UC IPM Advisor, these applications for GMB usually occur when there is between 6 and 10 inches of shoot growth--while we have mainly 1st and some 2nd instars in the population. It is not necessary to have all of the population exposed on the leaves, as there should be some activity of Applaud against a population on the canes or spurs.
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