BIOEFFICACY OF SOME CHEMICAL AND BOTANICAL INSECTICIDES AGAINST JASSID, AMRASCA DEVAS TANS ON BRINJAL AND THEIR IMPACT ON NATURAL ENEMIES

Abstract

An experiment was conducted at the experimental farm of Sher-e-Hangla Agricultural University Dhaka, during Feb-Aug 2007 to evaluate some chemicals and botanicals against jassid. Arnrasca devastans on brinjal and their impact on natural enemies. Nine treatments such as Admire 200S12, Ripcord IOEC, Marshal 20EC. Actara 24WG. Neern seed kernel, Neem oil -Trix, Trix, Mahua leaf extract and untreated control plots were used in Randomized Completely H lock Design (RCI3D) with 3 replications. The population of jassid adult gradually increased with plant age irrespective of treatments. The lowest population of adult (2.36 before fruiting stage and 9.80 during fruiting stage) and nymph (0.73 before fruiting stage and 1.67 during fruiting stage) per 5 lcaves/ plant was observed in Marshal 20EC treated plot. The yield contributing characters such as. number of leaves and branches/plant, number of fruits/plant, length, diameter and weight of individual fruit were found the highest in Marshal 20EC @ 2 mI/I treatments. The same treatment gave the highest yield (29.58 t/ha) and increased 44.65% yield over control. The maximum net return (330071 Tk./ha) and the highest benefit cost ratio (2.28) were also observed in Marshal 20EC. Admire 200Sl1 showed the similar performance in all regards against jassid on brinjal. Ripcord IOEC also gave the satisfactory results in reducing jassid infestation and increasing brinjal yield. Among the botanieals tested, Neem oil f Trix and Neem seed kernel showed satisfactory control of jassid on brinjal. Marshal 20FC. Admire 2005;L and Ripeord IOEC reduced more than 80% population of spidcr and lady bird hecile. Botanieals also decreased the population of spider and lady bird beetle over control but their effect was moderate.