Evaluation of the Efficacy of Chemical Insecticides and Biopesticides against Flea Beetle in Cabbage (Brassica oleracea var. Capitata)

Abstract

Aims: This study aimed to evaluate chemical insecticides and bio-pesticides against flea beetle in cabbage. Study Design: The experiment was laid out at a randomized complete block design with three replications. Place and Duration of Study: Experimental farm of Sher-e-Bangla Agricultural University, Bangladesh during the period from October 2017 to March 2018. Methodology: The experiment consisted of nine treatments viz. T1(Sevin 85 WP @ 2g/L of water), T2 (Decis 2.5 EC @ 1.0 ml/L of water), T3 (Voliam flexi @ 0.5 ml/L of water), T4 (Ripcord 10 EC @ 1.0 ml/L of water), T5 (Dursban 20EC @ 1 ml L-1 of water), T6 (Tobacco leaf extract @ 3 g L-1 of water), T7 (Neem seed kernel extract @ 3 g L-1 of water), T8 (Bioneem plus 1 EC @ 1 ml L-1 of water) and T9 (Untreated Control) were used at 7 days interval. Results: Stripped flea beetle(Phyllotreta striolata) and white-spotted flea beetle (Monolepta signata), these two species of flea beetle were found in the experimental field. Among all the treatments T4 (Ripcord 10EC)performed the best in managing flea beetles based on the lowest percentage of leaf infestation (5.84%), lowest no. of holes per plant (6.13), lowest percentage of head infestation by number (18.04) and highest percentage of infestation reduction over control on all parameters at vegetative stage of plant. Again, the lowest leaf infestation intensity (5.73%), lowest number of holes per infested head (14.00), lowest percentage of infestation of head by number (6.69) were achieved at harvesting stage from the same treatment (T4) whereas the highest values of all these parameters were achieved from untreated control treatment (T9). T4 treatment provided the best performance in yield where yield was increased (112.51 %) over control, giving maximum yield 75.76 tons ha-1. Bioneem plus 1 EC (T8) performed the best among the biopesticides while the neem seed kernel extract showed less effectivity against flea beetle. Conclusion: It is concluded that in case of chemical insecticides Ripcord 10EC while in case of biopesticides Bioneem plus 1 EC would be effective for flea beetle management.