Grape trees1/5/2024 This parasitoid can be highly effective late in the season to reduce mealybug populations present after harvest before they return to the roots or lower trunk to overwinter. This species has provided up to 20% parasitism in some vineyards in the Coachella Valley and up to 90% parasitism of exposed mealybugs late in the season in the San Joaquin Valley. The most successful of these has been Anagyrus pseudococci. The parasites that attack Pseudococcus mealybugs do not attack the vine mealybug therefore two potential candidates for biological control have been imported and released in California. Vine mealybug does not diapause during the winter, and it appears to be more sensitive to cold temperatures than grape mealybug. During summer when vine mealybugs are in the canopy, they can be located well above the fruit zone and will lay eggs on the leaves, while Pseudococcus mealybugs do not. In addition, the vine mealybug is much more likely to be found on leaves during the growing season than the other mealybugs. Other mealybugs found infesting grapes are only found on the aboveground portions of the vine. In the North Coast, vine mealybug has not been found on vine roots however, in other regions with sandy soils it spends the winter almost exclusively on the root system. Ants may transport vine mealybug from the roots to above ground plant parts where they continue to tend vine mealybugs throughout the remainder of the growing season. By late spring and summer, vine mealybugs are found on all parts of the vine: hidden under bark and exposed on trunks, cordons, first- and second-year canes, leaves, clusters, and roots. In other regions during the winter months, vine mealybug eggs, crawlers, nymphs, and adults are under the bark, within developing buds, and on roots.Īs temperatures warm in spring, vine mealybug populations increase and become more visible as they move from the roots or trunk to the cordons and canopy. In the North Coast during winter months, the only life stages found are nymphs located under the bark predominately at the graft union, on trunk pruning wounds, and below the base of spurs. There are three to seven generations a year.Īll or most life stages of the vine mealybug can be present year-round on a vine depending on the grape-growing region. The adult male is smaller than the female, has wings, and flies short distances to mate. ![]() The waxy filaments that protrude from the body of the vine mealybug are shorter than those on the Pseudococcus mealybugs, and the vine mealybug does not possess long tail filaments. The vine mealybug has a pinkish body that is visible through the powdery wax, and it is slightly smaller than the Pseudococcus mealybugs. Vine mealybugs are small (adult females are about 1/8 inch in length), soft, oval, flat, distinctly segmented, and covered with a white, mealy wax that extends into spines (filaments along the body margin and the posterior end).
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