Assessment of Different Modules for the Control of Whitefly Bemisiatabaci, (GENN) and Its Effect on Associated Natural Enemies in Okra

Abstract

The experiment was carried out to evaluate mechanical control and insecticides alone and in combination against whitefly Bemisia tabaci, (Genn) in okra Abelmoschus esculentus (L.) at farmer field, District Mardan Khyber Pakhtunkhwa during summer 2020.Randomize Complete Block Design (RCBD) was used with8 treatments including control (Yellow sticky traps, Yellow sticky traps + Ulala 50 WG, Yellow sticky traps + Pyriproxyfen 10.8% EC, Yellow sticky traps + Imidacloprid 25% WP, Yellow sticky traps + Ulala 50 WG+ Pyriproxyfen 10.8% EC, Yellow sticky traps + Ulala 50 WG+ Imidacloprid 25% WP, Yellow sticky traps + Pyriproxyfen 10.8% EC+ Imidacloprid 25% WP)replicated 3 times. The treatments were applied twice at 21 days interval except Yellow sticky trap which was applied weekly. All the tested treatments were found better than control in reducing whitefly population. Yellow sticky trap+ ulala+ imidacloprid was found the most effective treatment with lowest whitefly population (0.52 and 0.61 whitefly leaf^-1) and maximum percent reduction (87.4 and 68.4 %) after 1^st and 2^nd treatment application respectively, resulting in highest yield of okra (3762.3 kgha^-1) with cost benefit ratio (20.9). Results revealed that all the tested treatments where yellow sticky trap was used in combination with insecticides was comparatively more hazardous and had lowest ladybird beetle and green lacewing population than the treatment where yellow sticky trap was used alone. From the results it was concluded that yellow sticky trap used alone wasfavorable for natural enemies. Hence the use of yellow sticky trap in combination with ulala and alternate spray of imidacloprid at 21 days interval was found better at District Mardan and is recommended for sustainable management of whitefly in okra.