Seasonal incidence of grape mealy bug, Maconellicoccus hirsutus (Green) and its relation with weather parameters

Seasonal incidence ofgrape mealy bug, Maconellicoccus hirsutus (Green) was studied during 2005–2007 in relation to the prevailing as well as the previous (antecedent) four weeks (one/two/three/four lead weeks) weather. It was observed that the insect was prevalent throughout the year. Peak populations of 14.5 and 32.4 colonies per vine were observed during 36^th standard week in the vegetative and 10^th standard week in the fruiting season respectively. Mealy bug incidence correlated significantly and negatively with minimum temperature, bright sunshine hours and rainfall during real time and at three lead (previous) weeks, but positively with morning and afternoon relative humidities at two and three lead weeks respectively during pre-monsoon season. During the monsoon season, the mealy bug incidence correlated negatively and significantly with maximum and minimum temperatures at four and two lead weeks respectively. During post-monsoon season, the incidence of mealy bug correlated negatively and significantly with maximum temperature during real time. During winter season, which coincides with fruiting period, the association of mealy bug incidence was significant and positive with maximum temperature during the week of observation and at one and two leed weeks and negative with morning and afternoon relative humidity during the week of observation as well as at all individual lead weeks.