DEVELOPMENT OF INTEGRATED PEST MANAGEMENT PACKAGES AGAINST SPODOPTERA LITURA (FABRICIUS) IN TROPICAL SUGARBEET

Abstract

Five experiments were conducted of which one in the laboratory of Entomology division of Bangladesh Sugar crop Research Institute and four in the experimental field of Sher-eBangla

Agricultural University during November 2017 to May 2021. In the first experiment, we screened resistant sugarbeet varieties against Spodoptera litura and also asses the level of sugarbeet leaf and beet infestations caused by S.litura.The result showed that Cauvery was a best suited variety and PAC-60008 was most susceptible variety against S.litura. The highest (7.73) number of bore/plant and maximum (14.66) larvae were found in PAC-60008 variety while the lowest (2.20) number of bore/plant and minimum (2.00) larvae were observed in Cauvery variety. The yield of sugarbeet and its related parameters showed positive to Cauvery variety and negative to PAC-60008 variety. The highest yield 89.96 t ha- 1 was found in Cauvery and the lowest yield 76.06 t ha- 1 was found in PAC60008

variety. The Brix (18.23%) and Pol (13.45%) was highest in Cauvery and lowest (brix-14.70%, pol-11.18%) in PAC-60008. An integrated management for S. litura control is indoor residual spraying (IRS) that represents one of the main tools for evaluation of effectiveness of insecticides on different life stages of S. litura under laboratory condition. The lowest days of adult emergence and weight of larvae were found (19±0.5) days and (17.8±0.8) mg at T6 (Nitro 505EC solution @ 2.0 ml/lit of water) treatment. The highest (92.5 %) mortality at 3rd instar larvae of S. litura was found at T treatment. To identify the most effective insecticides for managing S. litura in tropical sugarbeet and determine the effective dose of insecticides to control the pest an experiment was conducted at field condition. As a result the T 3 (Nitro 505EC) and T 5 6 treatment (Virtako 40 WG) was the best suited and effective treatment against insect larvae compared to other. In order to evaluation the effectiveness of botanicals and non-chemical approaches against S. litura and find out the eco-friendly management practices an experiment was conducted at field level. The T

treatment (Neem Oil @ 3.0 ml/ lit of water) was showed the most effective treatment in this experiment. Finally, an integrate approaches for the best possible combinations of the tools identified from the previous experiment as effective against S. litura for safe and hazards free tropical sugarbeet production. The T treatment (Pheromone trap + Hand Picking + Nitro 505EC) was the best suited treatment. The highest (78.43 %) efficacy was observed in T 10 10 treatment as compared to other. The highest Brix (19.50 %) and the Pol (12.00 %) were found in T 10 treated plots followed by 18.66 % Brix and 11.83 % Pol were found in T

treatment. The highest (814.67 g) individual beet weight was found in T treated plot followed by 807.33 g in T (pheromone trap + hand picking + Virtako 40WG) where as the lowest individual beet weight was 722.67 g in T 9 (control) plot. It indicates that as the pest infestation increased so decreased the beet yield.