The Seasonal Incidence of Brinjal Shoot and Fruit Borer, Leucinodes orbonalis G.

Abstract

The present field investigation was conducted at Sirohi, Rajasthan, to study the seasonal incidence of brinjal shoot and fruit borer (Leucinodes orbonalis Guenee) in relation to prevailing weather parameters. Weekly observations were recorded from transplanting to final harvest on shoot and fruit damage, along with maximum and minimum temperature, relative humidity, and rainfall. During the crop period, the maximum temperature ranged from 32.4°C to 44.8°C, minimum temperature from 15.1°C to 30.9°C, morning humidity from 9.2% to 27.85%, evening humidity from 25.28% to 80.70%, and weekly rainfall up to 9 mm. The initial infestation was very low (0.2-0.5%) during the early vegetative stage (10th - 12th SMW) and gradually increased thereafter. A sharp rise in shoot damage (up to 3.0%) was observed during the 17th - 25th SMW, while fruit infestation increased markedly from 3.3% in the 16th SMW to a peak of 30.6% in the 23rd SMW. Pest incidence correlated positively with maximum temperature and evening relative humidity, showing that these variables have a positive impact on pest proliferation.  The infestation pattern revealed migration from shoots to fruits as the crop matured, resulting in substantial yield losses. The findings underscore the importance of timely monitoring and integrated pest management strategies to minimize losses caused by L. orbonalis in brinjal cultivation under Rajasthan’s climatic conditions.