Bio ecology and management of Scirpophaga fusciflua Hampson

Abstract

newline Detailed studies on white stem borer, Scirpophaga fusciflua (Hampson) were undertaken at Rice and Wheat Research Centre of CSK Himachal Pradesh Krishi Vishvavidyalaya at Malan during Kharif season 2015-2017. The studies included white stem borer annual life cycle, its population build-up, assessment of yield losses inflicted and management with suitable insecticides and biopesticides. Three generations of white stem borer were recorded under laboratory conditions. Life history of white stem borer comprised of four well-defined stages viz., egg, larvae, pupa and adult. At the end of the crop season, as the temperature decreased, the full grown larvae diapaused in rice stubbles, adult of which emerged during last week of April to first week of May under laboratory conditions. The female moths on an average laid 58.4 to 65.6 eggs in masses in different generations with pre-oviposition, oviposition and post-oviposition period of 23.8 to 24.1, 24.9 to 26.0 and 6.0 to 6.6 hours, respectively. The larva passed through five instars to complete the larval development and the head capsule width increased with each instar. Population build-up of S. fusciflua was undertaken at three locations viz., Kohala, Jia and Malan. The pest appearance initiated during the month of July and the peak activity of pest was recorded during the month of August and September. The adult population had a positive relationship with minimum and maximum temperature and relative humidity whereas, rainfall influenced adult population negatively. However, the larval population was found to be negatively correlated with minimum temperature, rainfall, relative humidity (morning and evening). The plant infestation was found to have significant negative correlation with temperature (maximum and minimum), relative humidity (morning and evening) and rainfall. Stepwise regression analysis based on the data clubbed for three cropping seasons (2015-2017) revealed that minimum temperature, maximum temperature and rainfall influenced light trap an