Seasonal fluctuation and extent of losses of Leucinodes orbonalis Guen. on Solanum melongena L.

摘要

The infestation of borer was started in third week of August with peak of 83.3 to 86.6% on top shoots in third week of September, with an intensity of 1.9 to 2.0 larvae/plant. On initiation of fruiting stage, there was a continuous decline in the shoot infestation which disappeared during fruiting stage in the end of October. As the borer infestation shifted to the fruits reaching at 60.0 to 66.6% on the basis of its counts and 56.5 to 56.6% by weight in the second week of October. The infestation gradually declined with the advent of winter season and completely wiped out by the end of November. The role of temperature, rainfall, relative humidity (morning) in increasing infestation and intensity on shoots and fruits was very conducive but relative humidity (evening) responded negatively. The apparent losses caused by borer on fruits were 19.4 to 20.2% whereas total losses were up to the tune of 35.2 to 36.4%, out of which avoidable losses were 34.0 to 36.1% but 0.3 to 0.4% losses were unavoidable as could be controlled even after application of protection technology.