SPECIES DIVERSITY OF FLEA BEETLES OF CABBAGE AND ITS MANAGEMENT USING CHEMICAL INSECTICIDES AND BIO- PESTICIDES

Abstract

A field experiment was conducted in the experimental farm of Sher-e-Bangla Agricultural University, Bangladesh during the period from October 2017 to March 2018 to evaluate the available species of flea beetles and their management practices in the cabbage. The experiment was laid out in a Randomized Complete Block Design (RCBD) with three replications. Nine treatments, viz. T 1 (Sevin 85WP @ 2 g L of water at 7 days interval), T 2 (Decis 2.5 EC @ 1 ml L -1 of water at 7 days interval), (T

(Voliam flexi @ 0.5 ml L -1 of water at 7 days interval), T 4 (Ripcord 10EC @ 1 ml L

of water at 7 days interval), T 5 (Dursban 20EC @ 1 ml L -1 of water at 7 days interval), T 6 (Tobacco leaf extract @ 3 g L -1 of water at 7 days interval), T (Neem seed kernel extract @ 3 g L -1 of water at 7 days interval), T 8 7 (Bioneem plus 1 EC @ 1 ml L of water at 7 days interval) and T (Untreated Control) were used. Two species of flea beetle were found in the experimental field, stripped flea beetle (Phyllotreta striolata) and white-spotted flea beetle (Monolepta signata). It was observed that T 9 treatment performed best in managing flea beetles attacking cabbage based on the lowest percentage of leaf infestation (5.84%), lowest number 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 (T ) whereas the highest values of all these parameters were achieved from untreated control treatment (T 4

treatment provided the best performance in yield where yield was increased (112.51 %) over control, giving maximum yield 75.76 ton ha -1 . Form the study it was found that there is a strong negative relationship between leaf infestation intensity and single head weight and between leaf infestation intensity and yield (t ha ) of cabbage. Moreover a strong negative relationship was observed between number of holes and weight of individual head and between percent head infestation and weight of individual head. -1 4 9 -1 -1 ). T 3 -1 4