Tips for limiting spider mite damage in vineyards
By CnAgri
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Because mites live underneath leaves, which shield them from sprays, they can be difficult to control with sprays. He recommends growers who use miticides to apply them before the canopy gets big, which may hinder penetration of the spray through the foliage.
However, he reminds growers that, depending on the material and mite population levels, a miticide treatment may not be effective against the various stages of mites present in the population. So an additional treatment may be required. In time, that can lead to development of resistance to the material. It is important to understand optimum timing—usually earlier rather than later. Looking for predatory mites is also important, since they may already be present in many vineyards.
McGourty favors an integrated biocontrol program using natural enemies to limit numbers of both Willamette and Pacific mites. These beneficials include six-spotted thrips as well as several commercially available predatory mites, like Galendromus occidentalis.
Some growers have achieved good success with Galendromus occidentalis, he notes, adding “These predatory mites, released at the rate of 5,000 per acre and preferably in the spring, come on bean plants that are placed in the canopy,” he says. “These predators scatter quickly, hunting for the pest spider mites, and they reproduce pretty effectively.
More information on controlling spider mites is available at http://ipm.ucanr.edu
