Vol. 18 No. 1
Seasonal abundance of different insect pests and predatory coccinellids in association with weather factors on bitter gourd, Momordica charantia L.
Author(s): K. Sen, P. P. Dhar and A. Samanta
Abstract: Seasonal incidence of important insect pests of bitter gourd along with natural enemies was studied during the springsummer seasons (2016 and 2017) at RRSS, Sekhampur and āCā Block Farm, Kalyani, West Bengal. Maximum activity of Diaphania indica was observed during April while the population of Aulacophora foveicollis, Henosepilachna septima, Bemisia tabaci and predatory coccinellids was recorded maximum during the months of April, May and June at Sekhampur and Kalyani in 2016 and 2017, respectively. Trap catches of Bactrocera cucurbitae was found maximum which varied in different weeks during February to June at both the locations in 2016 and 2017. At Sekhampur and Kalyani, maximum temperature and evening relative humidity had significant positive and significant negative correlation with the larval incidence of cucumber moth, whereas rainfall and morning relative humidity were significant and negatively correlated at Kalyani. At Sekhampur, minimum temperature, rainfall and relative humidity (morning and evening) were significant and positively correlated with red pumpkin beetle and epilachna beetle incidence, whereas at Kalyani, minimum temperature, rainfall and evening relative humidity had significant positive correlation with red pumpkin beetle, while maximum and minimum temperature were significant and positively correlated with epilachna beetle. At both locations, correlation between whitefly population and temperature (maximum and minimum) was found significantly positive while morning relative humidity showed significant negative relation at Kalyani. Temperature (maximum and minimum) and rainfall had significant positive relationship with fruit flies at Sekhampur, whereas correlation with minimum temperature, rainfall and evening relative humidity was recorded positively significant at Kalyani. Incidence of predatory coccinellids was positive and significantly correlated with temperature (maximum and minimum) at both locations but at Sekhampur, rainfall and morning relative humidity were also exhibited significant positive association.