Seasonal variations of sucking insect pests and associated natural enemies in cotton ecosystems of Odisha

This study assessed the seasonal dynamics of sucking insect pests and their natural enemies during the kharif season of 2021 at the Regional Research and Technology Transfer Station in Bhawanipatna, Odisha, from 30th to 52nd Standard Meteorological Weeks (SMW). Jassids (Amrasca biguttula biguttula) showed low initial numbers but increased significantly from the 34th week, peaking at 14.57 to 14.98 jassids per 3 leaves in the 42nd and 43rd weeks before declining, with a mean of 5.59±4.59 jassids per 3 leaves. Aphid (Aphis gossypii) populations peaked at 38.43 aphids per 3 leaves in the 34th week but then dropped to negligible levels, averaging 7.53±11.58 aphids per 3 leaves. Whiteflies (Bemisia tabaci) remained consistently low, peaking at 2.42 whiteflies per 3 leaves in the 46th week, with a mean of 1.00±0.68. Thrips (Thrips tabaci) increased from the 36th week, peaking at 10.22 per 3 leaves in the 38th week, with a mean of 3.01±3.42. Natural predators, including ladybird beetles, spiders, and green lacewings, peaked at 3.05 per plant in the 35th week, averaging 1.11±0.95. Weather factors significantly impacted pest and predator populations: minimum temperature correlated positively with jassids (r = 0.432) and predators (r = 0.673), while evening humidity correlated positively with jassids (r = 0.497) and thrips (r = 0.405). Rainfall significantly correlated with thrips (r = 0.582).