Seasonal Incidence of Rice Blue Beetle Leptispa pygmaea Baly (Coleoptera: Chrysomelidae) in Konkan Region

Field experiment to study the influence of weather factors on the leaves infestation by rice blue beetle, Leptispa pygmaea (Baly) were undertaken at the Agronomy farm, college of Agriculture Dapoli during Kharif season, 2013. The incidence of L. pygmaea commenced 2^nd week of July after transplanting of rice. The incidence on leaves was varied between 5.15 and 30.23 per cent during the crop season. Maximum incidence being in the 1^st week of September (30.23%) followed by 2^nd week of September (29.27%) coincided with flag leaf stage and panicle initiation stage. The correlation between weather parameters revealed that sunshine hour was significantly positively correlated (r =0.577) and rainfall were significantly negatively correlated (r =-630). The grub population reaches at peak in 35^th standard week (MW) with mean population of (11.96/hill) i.e. after seven weeks of transplanting. Maximum population of pupae (4.40/hill) and adult (4.86/hill) was found during 35^thstandard week (MW) i.e. second fortnight of August. The congenial weather factors during the high incidence viz., maximum and minimum temperature, morning and evening relative humidity, rainfall and bright sun shine hours were 28.70°C, 22.91°C, 93.14 and 85.86 per cent, 41.20 mm and 6.01 hours, respectively.