Population dynamics of rice yellow stem borer and sheath blight

Abstract

Field experiments were conducted on the seasonal incidence of yellow stem borer (Scirpophaga incertulas) and sheath blight (Rhizoctonia solani). These revealed that maximum deadheart incidence (5.32 and 5.64%) was observed in the 33rd and 34th standard meteorological week (SMW) in 2018 and 2019, respectively. The incidence of white earhead was maximum (4.96 and 5.28%) during 40th SMW. Maximum incidence of sheath blight (50 and 46.67%) was noticed during 36th SMW. A significant positive correlation of minimum temperature and evening relative humidity was found with deadheart incidence. Conversely, maximum temperature and morning relative humidity had significant positive correlation with incidence of sheath blight. The model developed for ascertaining effect of weather factors on incidence of pest and disease showed a good relationship between predicted and observed data of % deadheart (R2=0.996), white earhead (R2=0.992) and diseased plants (R2=0.986).