FIELD EFFICACY OF SOME SELECTED INSECTICIDES AND BIOPESTICIDE AGAINST SUCKING PESTS ON OKRA

Abstract

Okra, Abelmoschus esculentus (L.) Moench is a popular vegetable grown in Bangladesh and throughout the cropping season, the crop is vulnerable to many types of sucking pests. A field experiment was conducted in the research field of the Department of Entomology, HSTU, Dinajpur, to evaluate the field efficacy of five selected insecticides and biopesticide against sucking pests on okra during February to June, 2023. The selected insecticides and biopesticide namely imidacloprid (Imitaf 20 SL), acetamiprid (Tundra 20 SP), emamectin benzoate (Emacto 5 WDG), spinosad (Trace 45 SC), lamda-cyhalothrin (Fighter 2.5 EC) were applied at 10 days intervals in the field. The experiment were done with RCB design with three replications and data were recorded on the number of whiteflies, jassids, curled or infested leaves /3 leaves at one day before 3, 7 and 10 days after each spray. The marketable fruits were harvested at 3 days interval and weight of fruits was also recorded. The results showed that the lowest cumulative mean number of whiteflies was found (2.67, 1.33 & 0.77/ 3 leaves) in the treatment of imidacloprid (Imitaf 20SL) after 1st, 2nd and 3rd sprays, respectively. On the other hand, the highest cumulative mean number of whiteflies was found (5.00, 7.56 and 12.88 / 3 leaves) in the control. The highest percent decreased of whiteflies over control was 46.60, 82.41 and 94.02 % observed in the treatment of imidacloprid (Imitaf 20SL) after 1st, 2nd & 3rd sprays. In case of jassid population, the lowest cumulative mean number (1.44, 1.11 and 0.77/3 leaves) of jassids was recorded from the treatment of imidacloprid (Imitaf 20SL), contrarily the highest cumulative mean number (4.11, 7.11 and 5.55 / 3 leaves) of jassids was recorded from the control. Consequently, the highest percent decreased of jassids over control was found 65.00, 84.39 and 86.13 after 1st, 2nd & 3rd sprays when applied imidacloprid (Imitaf 20SL). The cumulative yield was the highest (2.22 kg/ plot) with the highest benefit cost ratio (1.50) was recorded in the treatment of imidacloprid (Imitaf 20 SL). Based on the experiment, it may suggest that okra field can be treated with imidacloprid (Imitaf 20 SL) to reduce the number of population of sucking pests like jassids and whiteflies for better yield.