STUDY ON HOST PLANT PREFERENCE OF APHID (Aphis gossypii) IN DIFFERENT FIELD CROPS AND THE PREDATION EFFICACY BY LADYBIRD BEETLE (Coccinella septempunctata) ON APHID

Abstract

The study on host plant preference of aphid and predation efficacy of ladybird beetles on aphid was conducted at Sher-e-Bangla Agricultural University central farm and the laboratory of the Department of Entomology, SAU during November 2020 to April 2021. Two experiments were conducted to explore the host plant preference of aphid and the predator efficiency of ladybird beetle. They were laid out in Randomized Complete Block Design (RCBD) for field condition and Complete Randomized Design (CRD) for laboratory condition with 3 replications. There are six different crops as treatment-wheat, brinjal, tomato, potato, country bean and mustard. The highest number of aphid (54.51 plant -1 ) was recorded in Country bean at 7 DAS and the lowest (8.00 plant -1 ) number of aphid was recorded in Brinjal plant at 35 DAS. The highest number of aphid (29.67 leaf -1 ) was recorded in Country bean at 35 DAS and the lowest (8.00 leaf -1 ) number of aphid was recorded in Wheat plant at 14 DAS. The highest number of aphid (9.67 inflorescence -1 ) was recorded in Country bean at 14 DAS and the lowest (3.00 inflorescence -1 ) number of aphid was recorded in Wheat plant at 14 DAS. The highest number of aphid (15.67 twig -1 ) was recorded in Country bean at 7 DAS and the lowest (11.00 plant -1 ) number of aphids was recorded in Brinjal plant at 35 DAS. The highest number of aphid (6.00 pod -1 ) was recorded in Country bean and the lowest (5.94 pod -1 ) number of aphids was recorded in Brinjal plant. The highest consumption of aphid (3.10 aphid) by Ladybird beetle was recorded in Country bean at 12 hours interval and the lowest consumption of aphid (1.10 aphid) by Ladybird beetle was recorded in Wheat at 6 hours interval. The adult ladybird beetles was more efficient in predating aphid and the highest consumption of aphid was recorded from adult ladybird beetles.