Seasonal Incidence of Dipha aphidivora Meyrick (Pyralidae:Lepidoptera) in Bhadra Command Areas

Investigation on the seasonal incidences of Dipha aphidivora Meyrick (Pyralidae: Lepidoptera) and its natural enemies from June 2005 to May 2006 undertaken at Agricultural Research Station, Honnavile, Bhadravathi and Shimoga district revealed an incidence ranging from 1.6 to 7.2 larvae per plant recorded at Shimoga district (Location I, Shettihalli), 1.1 to 7.9 larvae per plant at Shimoga district (Location II, Honnavile), 0.7 to 6.9 larvae per plant at Bhadravathi taluk (Location III, Barandur) and 1.2 to 6.5 larvae per plant at Bhadravathi taluk (Location IV, Tadsa). The highest incidence of 7.2, 7.9, 6.5 larvae per plant was observed during October month at Shimoga district, (Location I, Shettihalli), (location II, Honnavile) and Bhadravathi taluka (Location IV, Tadsa) and 6.5 larvae per plant was observed during September month at Bhadravathi taluk (Location III, Barandur). The lowest population of 1.6 and 1.1 larvae per plant was recorded during July month at location I, II, 0.7, and 1.2 larvae per plant was recorded at location III and location IV. The D. aphidivora population had two peaks in a year one at October and another at January. The correlation between the D. aphidivora population and weather parameters revealed that the incidence of D. aphidivora was negatively correlated with minimum temperature, maximum temperature and rainfall and positively correlated with relative humidity in all the four locations. The correlation between D. aphidivora population and SWA population showed significant positive correlation at location I, location III and location IV and non-significant negative correlation at location II. The natural enemies recorded on D. aphidivora were the field lizards and an unidentified bird, which devoured D. aphidivora. No parasites were recorded on D. aphidivora.