Exploration of Predatory Spiders on Cotton Pests in Sprayed and Un-Sprayed Cotton Fields of Ccri-Sakrand-Sindh-Pakistan

Abstract

Explorations of predatory spiders were carried out from sprayed and unsprayed cotton crop grown at Central Cotton Research Institute Sakrand, Sindh-Pakistan during the period of May-October 2016 and 2017. During the research findings eight species of predatory spiders were explored and identified from cotton field which were Philodromus cespitum, Thanatus formicinus, Thyene imperialis, Oxyopes salticus, Cheiracanthium erraticum, Plexippus Paykulli, Lycosa tista and Pardosa birmanica. The activity of predatory spiders started in the month of May and June in the initial stage of cotton crop during the both years. The maximum spider population was noted in the months of July and August, when cotton crop was fully mature. The population of predatory spiders increased 61 in un-sprayed plot and 28 in sprayed in 2016 and 43 numbers of predatory spiders in un-sprayed plot and 22 in the sprayed plot during 2017. The maximum mean number of spiders was found to be 69 in un-sprayed plot and 36 in sprayed plot in 2016 as compared to 54 and 26 in 2017. Number of spiders were lesser in the month of September and October, the population of spiders decreased with the less population of sucking insect pests due to mature age of cotton crop in both plots in 2016 and 2017. There is a dire need to explore the insecticide effects on the predatory spiders of Pakistan and protection to keep the spiders safe from indiscriminate use of insecticides on cotton crop as they are bio-control agents and contribute their big part in the agriculture ecosystem, food chains and control of arthropods.