EVALUATION OF SOME CHEMICAL INSECTICIDES IN CONTROLLING MAJOR INSECT PESTS OF OKRA (A belmoschus esculentus)

Abstract

An experiment was conducted at Sher-e-Bangla Agricultural University (SAU). Dhaka. during April to July. 2006 to evaluate the effectiveness of' different chemical insecticides against three major insect pests: Jassid (Arnrasca devastans), Whitefly (Bernisia tabaci) and Okra Shoot and Fruit Borer (OSFB) (Earias vine/Ia) of okra, which are serious problem for its production. At vegetative stage against Jassid and Whitefly three treatments comprising Admire 200 SL. Aetara 25 WG and control were tested. Lowest number of virus infected plants and leaves and also the lowest avenge population of Jassid (133) and White fly (1.86) were found in Admire 200SL treated plots and the highest in control plots (6.75 and 7.36). For the management of OSFB nine treatments comprising seven insecticides (eg; Cymbush 10 EC, Decis 2.5 EC. Shohicron 425 EC, Karate2.5 EC, Regent 50 SC, Fenfen 20 EC & Suntap 50 WP); mechanical control and untreated control, were evaluated using 'BAR!Dherosh-1' laid out in RCBD with 3 replications. Highest infestation of shoot (27.35%) and fruit at early, mid and late reproductive stages (13.82%. 12.64% and 24.60% by number) and (26.06%, I 3.78%& 27.67% by weight) was observed in the control plots, which was significantly highest from all other treatments. Fenfen 20 EC @ 0.5 mI/I of water gave the best performance resulting lowest shoot infestation (3.95) and fruit infestation at early. mid & late reproductive stages (1.09%, 1.61% & 4.11 % respectively by number) and (3.92%, 2.29% & 8.37% respectively by weight) and provided highest yield (12.97 ton/ha). Thus the lowest number (0.26, 0.43 & 0.83) and weight (17.13, 11.38 & 32.67gm) of infested fruit per plant, maximum fruit length (15.54. 16.01, 14.10 cm) and breadth (1 .89, 1.82 & 1.74 cm) at early, mid & late reproductive stages and maximum height of okra plant (109.88cm) were observed in fenfen 20 EC treated plots. Decis 2.5 lx @ I mi/of water at 7 days interval also gave statistically similar results for different parameters tested.