Efficacy of Stem Application on Pests and Natural Enemies Associated with Cotton
2021
Prasad, B Ram | Sudarshanam, A
After advent of Bt cotton, sucking pests have become a major constraint in cotton causing 22.85% loss under rainfed conditions. Farmers use insecticides against these, which not only affect the beneficial insects but also leads to insecticide resistance. Hence, this study explores a cost effective and ecofriendly method of stem application. The application done @ 30, 45 and 60 days after sowing (DAS) has evaluated flonicamid, thiamethoxam, fipronil, acetamiprid, clothianidin, imidacloprid and monocrotophos during 2015-17. The results revealed that aphids are effectively reduced by monocrotophos, water @ 1:4 (4.4/ 3 leaves) followed by acetamiprid, water @ 1:20 (5.3/ 3 leaves). Flonicamid, water @1:20 significantly contained jassids (1.5/ 3 leaves) followed by monocrotophos, water @ 1:4 (2.0/ 3 leaves). None of the insecticides had a significant effect on thrips; acetamiprid, water @ 1:20 was found somewhat better. Against whitefly, flonicamid and fipronil were found superior. Natural enemies were significantly less disrupted by stem application method. The maximum seed cotton yield (2603 kg/ ha and 2431 kg/ ha) was obtained with monocrotophos, water @ 1:4 and flonicamid, water @1:20, followed by fipronil, water @1:4 (2413 kg/ ha).
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