Seasonal incidence and prediction model of grapevine mealy bug (Maconellicoccus hirsutus Green)

Study on seasonal incidence of grapevine mealy bug revealed the reduction in its population at every pruning (September and April) but reached at its peak during full vegetative growth (2nd -12th MSW), i.e., fruiting season. The incidence of mealy bug was observed throughout the season. The incidence of parasitoids was seen throughout the season except 12^th, 14th and 16th meterological week (MSW) on mealy bugs. However, predators were found absent during fruiting season, i.e., 50th to 12^th meteorological standard week (MSW). The weather parameters viz., maximum temperature and bright sunshine hours showed significant and positive correlation, but minimum temperature, morning and afternoon relative humidity and rainfall correlated negatively with mealy bug incidence. The model (LW₁ = 68.03 -0.6X₃) developed can be used to estimate population development of mealy bugs one week early, so that one can initiate management practices to reduce the population build up.