author(s)
Anitha G, Shashibhushan V, Chitra Shanker, Srinivas C and Uma Devi G

abstract
A study was conducted to understand the impact of insecticides on spiders and predatory coccinellids in different cultivation systems of rice. The experiment was laid out in the College Farm, College of Agriculture, Rajendranagar in kharif seasons of 2014-15 and 2015-16 in a split plot design, where rice crop was grown in the form of three main modules with three different methods of establishment viz., transplantation, broadcasting and drumsown rice with three sub-modules under each main module viz., organic protection, farmers’ practices and ‘no protection’. Need based application of plant protection measures was taken up in the farmers’ practices and organic protection practices. Data on spiders and predatory Coccinellids counts taken before and after the imposition of treatments revealed that significantly higher predator numbers were observed in ‘no protection plots” > organic protection plots > farmers’ practices in both the years of study. At three days after spray, transplanted ‘no protection’ plots recorded significantly highest number of spiders (27.18/quadrat), while at seven and fifteen days after spray, drumsown ‘no protection’ practices recorded significantly higher predator numbers compared to the other treatment (29.04 and 31.36 spiders/quadrat respectively). Similarly, Coccinellids were found to be in significantly higher numbers in transplanted ‘no protection’ plots’ at three and seven days after spray (20.82 and 22.48 spiders/quadrat), while at fifteen days after spraying, drumsown ‘no protection‘ plots recorded significantly higher populations of the beetles (23.63 beetles/quadrat). Significantly lesser population of the beetles at three and seven days after spraying were observed in drumsown ‘farmers’ protection’ plots (10.51 to 12.56 beetles/quadrat), while in the farmers’ practices plots of transplanted and broadcasted modules, significantly least beetle number (14.46-14.48 beetles/quadrat) were recorded.