author(s)
M Baruah and BC Dutta

abstract
The field experiment was conducted in the rice field of Regional Agricultural Research Station, Assam Agricultural University, Titabar, Assam in randomized block design sowing the seeds in three dates at an interval of twenty days between each sowing, viz., early (15^th May), normal (5^th June) and late (25^th June) separately. Early sown was the least damaged crop ( 9.6% dead heart (DH) and 10.3% white ear head (WEH) as compared to normal (15.5 % DH and 16.7% WEH) and late (24.6% DH and 25.3% WEH) with a yield of 5.3t/ha in early, 4.5 t/ha in normal and 2.4t/ha in late sown crops. Spider population was significantly higher in early than that of normal and late planting, whereas the population of coccinellid beetles and the egg parasitoid, Trichogramma japonicum were non-significantly higher in early than that of normal sown crop, but the population of these natural enemies were significantly lower in late sown rice. The stem borer infestation was significantly higher in late sown crop with increased maximum temperature, morning humidity having a significant positive effect in all the dates of planting. There were a non- significant positive effect on population with minimum temperature (r = 0.34 for DH and r = 0.22 for WEH) and average rainfall (r = 0.20 for DH and r = 0.07 for WEH) at early sown. Maximum temperature and morning relative humidity had a significant positive effect on borer infestation as dead heart and white ear head in connection with a significant positive effect of spider population in three dates of planting. The variation in the planting times work as a means of cultural control by creating asynchrony between crop and insect pests’ phenology along with crop-weather-pest interaction help in developing forewarning system to warn the farmers in advance to avoid manageable yield loss by stem borer incidences.