Survey and Population Density of Sesame Pests and Associated Natural Enemies

Abstract

The present studies were carried out in farmer fields cultivated with sesame Sesamumindicum L variety Shandaweelduring 2021 and 2022 seasonsat Abo Hammad district, Sharkia Governorate, Egypt, to survey the pests, natural enemies associated with sesame plants and to study the population density of the main and dominant pests. The pests recorded relatively high mean numbers were leafhoppers species, two spotted spider mites,green peach aphids, onion thrips and green stink bugpests were recorded relatively high mean numbers followed by whiteflyand last species in very low numbers. In addition, four species of insect predators and one predatory mite was found associated with pests on sesame plants in very low numbers. The occurrence periods and population fluctuation of main pestsspecies i.e., Empoasca spp., Myzuspersicae, Nezaraviridula, Thripstabaci and Tetranychusurticae were investigated.TheEmpoasca spp. infested sesame plants from June to end of September during the two seasons, with relatively highest peak of 49.5 individual/ leaf on 13 th August during 2021. The occurrence periods of the green peach aphids, were extended from April to October recorded relatively highest peak of 43.25 individual/ leaf on 27 th August during the 2022 season for the green stink bug it was infesting plants recording (7.75 and 8.25 individuals / leaf) on 16 th and 23 th Jul. during two seasons, respectively. In the same trend the Green stink bug and onion thrips infested sesame plants from June to September during the two seasons with relatively highest peaks of 8.25 individual/ plant and 22.25 individual/ leaf at 2022and 2021 seasons for the two insects, respectively. Also, the Twospotted spider mites T. urticae was occured sesame plants from June to September during the two season recorded relatively high peak of 37.5 individual/ leaf recorded at 2 nd July during 2021. The effects of metrological factors on pests population were varied where the highest significant effect of 65.29 % was recorded as combined effect (E.V