Abstract

The bioefficacy of insecticides against the rice leaf mite,Oligonychus oryzae, Hirst (Acarina: Tetranychidae) was studied under laboratory and field conditions at PAJANCOA and RI, Karaikal. The lab study revealed that among the 11 treatments, methyl demeton 25 EC at 0.42 per cent concentration was superior against nymph and adult mites. Novaluron 10 EC and dicofol 18.5 EC were on par with methyl demeton 25 EC. All the three concentrations of profenofos 50 EC, hostothion 40 EC, mit 50 EC, propargite 57 EC and milbemectin 1 EC were on par with each other. The LC50 values of profenofos, hostothion were 0.002 and 1.165 respectively. Thus methyl demeton followed by novaluron exhibited more ovicidal, nymphicidal and adulticidal effects. Among the acaricides, methyl demeton 25 EC at 1000 ml/ha and novaluron 10 EC at 1000 ml/ha were the best treatments in reducing the population of mite and were equally effective at 1,3,7 and 14 days after treatment, followed by milbemectin under field condition. Botanicals did not achieve effective control compared to insecticides, but they were less effective against the rice mite.

Keywords: insecticides, rice leaf mite, botanicals, entomopathogens.