Incidence and distribution pattern of leaf webber (Orthaga exvinacea Hamp.) on mango
N Kasar, JC Marak, UK Das and S Jha
A field investigation was carried out to study the incidence and distribution pattern of mango leaf webber, Orthaga exvinacea Hampson during 2012-13 and 2013-14 at mango orchard of Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, Nadia, West Bengal. The results indicated that the most active period of mango leaf webber in both years was found from August to December. The distribution study of leaf webs within the tree revealed that western and southern side had more number of webs in comparison to the northern and eastern side respectively. The differences were statistically significant. Correlation results indicated that maximum and minimum temperature had negative and significant effect (r = -0.796** and -0.755**, respectively) on the leaf webber population. However, relationship of morning relative humidity (r = +0.328**) was positively significant and evening relative humidity (r = -0.239) was negative and non-significant. Total rainfall (r = -0.370*) had negative and significant influence on leaf webber population.