Population dynamics, weather parameters interaction of insect pests on Indian bean, Lablab purpureus and prediction analysis using ARIMAX model

Abstract

Aim: The present study was conducted to find out the dynamics of insect pests in Indian bean, Lablab purpureus during different season at Lower Pulney hills in Tamil Nadu and to predict the occurrence of insects/pests for management practices. Methodology: Field trial was conducted in the rain fed Hill Avarai, Lablab purpureus (Linn.) at Thandikudi village of Lower Pulney hills to study the population dynamics and weather factors interaction with sucking pests, leaf, flower eating insects and pod borers. Forecast modeling of major pests of hill avarai were done with ARIMAX analysis. Results: Around 21 insect species belonging to four major insect orders viz., Hemiptera, Lepidoptera, Coleoptera, Orthoptera with division of three categories namely sucking insects, leaf, flower eating insects and pod borers. Among them the occurrence of sucking pests was maximum and damage followed by leaf, flower eating insects and pod borers. All sucking pests, leaf, flower-eating insects and pod borers showed positive correlation with maximum and minimum temperature, while relative humidity, rain fall and wind speed had negative correlation with sucking pests, however, positive correlation was observed with leaf, flower-eating insects and pod borers. Interpretation: Under temperate conditions biotic factors such as maximum and minimum temperatures have an important impact in Indian bean pest population fluctuation. ARIMAX model created in this work could be used to forecast the appearance of significant major pests of bean such as A. craccivora, L. trifolii, and M. vitrata in the subtropical areas of Tamil Nadu, India.