English

Abstract

The field experiment conducted during Kharif 2008-09 and 2009-10 on evaluation of certain new insecticides indicated that spinosad 0.015 per cent was found most effective in reducing the population of S. dorsalis as well as in increasing yields. It attains highest cost benefit ratio followed by diafenthiuron 0.045%, pymetrozine 0.02% and fipronil 0.01%. Indoxacarb 0.015 % and flubendiamide 0.012 %. Further flubendiamide recorded the lowest mean per cent reduction over untreated check indicating their poor efficacy against S. dorsalis on chillies. th chillies contributing to almost 1/4 of the world's production. In India, chilli is grown in an area of 8.06 lakh ha, with a production of 12.98 lakh tonnes (Agricultural Statistics at a glance, 2009). The important chilli growing states in India are Andhra Pradesh, Orissa, Maharashtra, Karnataka and also in a number of other states as a round the year crop. In Andhra Pradesh, chilli is cultivated in an area of 1.89 lakh hectares with a production of 2.08 lakh tonnes. Guntur district in Andhra Pradesh alone contributes to over 35 per cent in area under chilli crop in India. The important pests are thrips, Scirtothrips dorsalis (Hood), white mite, Polyphagotarsonemus latus (Banks), aphids, Aphis gossypii Glover and Myzus persicae Sulzer as sucking complex and tobacco caterpillar, Spodoptera litura (Fabricius) and pod borer, Helicoverpa armigera (Hubner) as pod borers (Rao and Ahmed, 1985). Chilli thrips, Scirtothrips dorsalis (Hood) (Thysanoptera : Thripidae) is a serious pest of Capsicum annuum L. in India, responsible for leaf curling (Ananthakrishnan, 1971). It multiplies appreciably at a faster rate during dry weather periods and the yield loss caused by the thrips is reported to range from 30-90 per cent (Borah, 1987 and Varadharajan, 1994). Guntur district in Andhra Pradesh is traditionally a chilli growing district with an area of 63,573 ha with high input usage under monocropping conditions. Further, intensive cultivation of input responsive high yielding varieties and hybrids and sole reliance on insecticides are the common features of chilli cultivation in Guntur district. The excessive dependence on insecticides, their over use and abuse has accelerated insect control problems through development of insecticide resistance (Reddy et al., 1992), pest resurgence, pesticide residues (Joia et al., 2001), reduction in natural enemy population and environmental contamination. Moreover, several of the chilli consignments meant for export were rejected stating higher insecticide residues being the culprit, thus lots of foreign exchange lost by way of rejections. Further there were several reports from farmers experiencing difficulties in pest control. Many conventional insecticides are being used to manage these pests with which many folds of resistance was reported in pests like S. litura (Prasad et al., 2008), Spodoptera exigua (Hubner) (Wang et al., 2002), H. armigera (Kranthi et al., 2002) etc. The occurrence of insecticide resistance strains can be reduced or delayed by reducing the selection