Alternate hosts and seasonal carry-over of eggplant shoot and fruit borer, Leucinodes orbonalis Guenee (Lepidoptera: Crambidae)

Leucinodes orbonalis causes huge losses in eggplant (Solanum melongena) making its cultivation economically difficult. During off-season insect pests survive and multiply on alternate hosts, so it is indispensable to identify all of the sources of carry-over for efficient management. This study aimed at identifying the carry-over sources of L. orbonalis and consisted of three components, namely rapid roving surveys for collecting and identifying alternate/ collateral hosts, free-choice test for host preference studies, and carry-over from eggplant crop to other hosts. During roving survey, shoot samples of the possible alternate hosts were collected from farmers’ field of the six districts to confirm the presence of the larval stages of L. orbonalis. Out of the collected alternate hosts, eight were found to harbor the L. orbonalis, four of which were vegetables and four were weed hosts with majority of them belonging to family Solanaceae. Based on free-choice test, among the eight alternate hosts identified from survey studies, Solanum nigrum, Solanum tuberosum and Solanum lycopersicum were the most preferred hosts. For the third component of the study, pheromone traps were installed in different season eggplant crops. Based on the pheromone trap catch, ratoon crop left standing as such was the major source of carry-over, followed by pruned ratoon crop and uprooted stalks. In conclusion it is imperative to manage alternate hosts, and ratoon crop and uprooted stalks of eggplant for efficient management of the L. orbonalis with least use of chemical insecticides.