Influence of abiotic factors on stem borer incidence and species distribution in rice (Oryza sativa L.)

Abstract

Aim: To evaluate the effect of abiotic factors such as temperature, relative humidity, wind velocity, sunshine hours and rainfall on the distribution and relative abundance of stem borer species in rice ecosystem. Methodology: Seasonal incidence of stem borer species was monitored using light trap catches and were correlated with the weather parameters. The relative abundance of stem borer species during Kharif and Rabi was estimated based on light trap catches and larval incidence. Results: Seasonal incidence revealed the occurrence of three stem borer species (yellow stem borer, pink stem borer and dark headed borer) populations in rice ecosystem. Yellow stem borer was found to dominate in rice ecosystem during Kharif, (80.61%) whereas during Rabi, pinkstem borer was found to be dominant (72.60%) than yellow stem borer (21.92%) and dark headed borer (5.48%). Weather parameters such as temperature, rainfall and wind velocity negatively influenced the occurrence of stem borer species in rice, whereas relative humidity and sunshine hours had positive effect. Regression analysis revealed the increased effect of abiotic factors such as temperature, relative humidity and wind velocityon the population of pink stem borer against yellow stem borer and dark headed borer. Interpretation: The present study reveals that, the change in weather parameter during seasons, such as temperature (25 - 27°C), relative humidity (69 - 80 %) and wind velocity (3 - 4 km hr-1) increased the fitness of pink stem borer species population than yellow stem borer and dark headed borer species in rice ecosystem, which was evidenced by the occurrence and relative abundance of pink stem borer population during Kharif 2018 and Rabi 2019 respectively.