Efficacy of some compounds against Thrips tabaci Lind. infesting onion plants at Sohag Governorate, Egypt

Abstract

Onion, Allium cepa L., is one of the most valuable vegetable crops in Egypt. Thrips tabaci Lind. is the most damaging insect pest attacking onion plantations in the field. The present study was conducted at the Farm of Shandweel Agricultural Research Station, Sohag Governorate, Egypt during 2020/2021 and 2021/2022 seasons to evaluate the efficacy of some compounds against T. tabaci infesting onion plants. The effectiveness of three chemistry synthetic insecticides (emamectin benzoate, spinetoram and pyridalyl), two microbial insecticides ( Bacillus thuringiensis and Trichoderma longibrachiatum ) and two botanical extracts (garlic and chili), in addition to mineral oil against onion thrips was evaluated under field and laboratory conditions. In the field, data indicated that synthetic chemical insecticides gave higher reduction than other treatments in both seasons. Depending on the general mean, the highest reduction was observed on spinetoram in the two seasons. For safe materials, only chili extract gave reduction > 50%, with mean reduction percentage of 51.06% in 2021/2022 season. In laboratory, data clearly indicate that the tested compounds could be descendingly arranged based on LC 50 values as follows: spintoram, emamectin benzoate, pyridalyl, chilli extract, Garlic extract, Bacillus thuringensis , Trichoderama longibrachiatum , mineral oil.