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University of California Cooperative Extension Site maintained at the Kearney Agricultural Center by KM Daane (UC Berkeley) and WJ Bentley (UC Statewide IPM Project) © The
Regents of the University of California |
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Seasonal abundance & distribution Monitoring Chemical controls Cultural controls
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The grape mealybug can be a serious pest throughout the San Joaquin Valley, in some regions of the North Coast, and in the warmer regions of the Central Coast. This mealybug is thought to be native to North America and is found throughout the United States. Grape mealybug is also found on apple, pear, apricot, and pomegranate. (Return to top) |
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Seasonal
abundance & distribution Grape mealybug population densities are dependent on vine vigor and pruning methods. Like several other mealybug species, this one prefers more vigorously growing vines. Spur-pruned vines tend to suffer greater damage because the fruit often rests in close proximity to woody parts of the vine where grape mealybugs exist in the largest densities.
Grape mealybugs overwinter under the bark either as eggs in a white, cottony ovisac or as first- or second-instar nymphs. As temperatures warm in spring, the young nymphs move from the old wood onto the developing green shoots and leaves to feed and develop. Once these individuals mature in early to mid summer, they return to the old wood to oviposit. Each adult female lays 100 to 300 yellow-to-orange eggs within an ovisac. These eggs hatch in 7 to 14 days, and the crawlers move out to the fruit to feed and develop. This brood develops into adulthood in late summer and early fall. Many of these females return to the old wood to lay the overwintering eggs. However, some adult females that develop in late summer oviposit in the fruit clusters. (Return to top)
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