Bio-efficacy of Newer insecticides against diamondback moth (Plutella xylostella linn.) on Cabbage under poly house condtion

Abstract

An investigation on "Sic-efficacy of newer insecticides against diamondback moth (Piutella xy/ostella Linn.) on cabbage under poly house condition". was carried out at Sericulture Research Demonstration and Training Unit, Department of Entomology, Sardar Vallabhbhai Patel University of Agriculture and Technology, Meerut during Rabi 2012-13. The experiment was comprised of seven treatments and laid out in randomized block design with three replications. During the crop season, eight insect-pests were found attacking on the crop at different growth stages. Among them, diamondback moth, cabbage aphid, cabbage butterfly, and tobacco caterpillar were recorded as major pests. The cabbage semilooper and flea beetle were recorded as 'minor' pests. The rest of the insect pests' viz., crucifer leaf-webber and cabbage webworm in experimental period were recorded as 'stray' pests. The population of diamondback moth infesting cabbage crop was recorded during, first and second week of November and reached the peak in the third week of December and second week of January. The DBM population was negatively correlated with mean temperature and Abstract. .. .... xii positively correlated with relative humidity and rain fall. Cabbage aphid started damaging the crop initially during second week of November and reached to its peaked level in third week of December. Its population showed the significant negative correlation with temperature and relative humidity, while positive correlations with rain fall. The initial incidence of cabbage butterfly and tobacco caterpillar was observed during third week of November and subsequently reaching to while to peak level on last week of January. The efficacy of different insecticides viz, coragen 18.5 SC, spinosad 45 SC, indoxacarb 14.5 SC, lambda cyhalothrin 5 EC, thiamethoxam 25 WG and carbosulfan 25 EC, was evaluated on diamondback moth, cabbage aphid, cabbage butterfly, and tobacco caterpillar infesting cabbage. All the treatments were found significantly effective in reducing the infestation of diamondback moth, cabbage aphid, cabbage butterfly, and tobacco caterpillar. The most effective treatment in reducing the infestation of all these insects was coragen 18.5 SC, followed by spinosad 45 SC, indoxacarb 14.5 SC, lambda cyhalothrin 5 EC, thiamethoxam 25 WG and carbosulfan 25 EC respectively. Carbosulfan (800 ml/ha) was, however found least effective but was significantly superior over control. The maximum net return was obtained from indoxacarb 14.5 SC treated plots as the cost: benefit ratio of this treatment was highest (1 :9.18). Carbosulfan 25 EC was found the least cost benefit ratio (1 :4.85).