Relative efficiency of some of the common insecticides and their joint formulations with carbaryl against the tea mosquito bug (Helopeltis antonii signoret) infesting cashew trees

Abstract

The relative efficiency of endosulfan (0.05%), phosphamidon (0.03%), monocrotophos (0.05%), carbaryl (0.15";,) and HCH (0.15%) and their joint formulations with carbaryl against the tea mosquito bug Helopeltis antonii Signoret was evaluated in a field experiment conducted in the Cashew Research Centre, Madakkathara, Trichur during two consecutive years 1 980-81 and 1 981 -82. Three rounds of sprayings were given in each year using a rocker sprayer Fitted with 'hi-tree' lance attachment at the times of new vegetative flush formation, panicle emergence and at fruit set initiation. The intensity of pest damage was recorded from twenty numbers of randomly selected shoots and panicles on a 0-4 scale. All the insecticides and their joint formulations were effective in reducing the intensity of damage by the mosquito bugs. Ths joint application of phosphamidon (0,015%) + carbaryl (0.075^) was consistently superior to endosulfan (0.025%) + carbaryl (0.0755') and HCH (0.15#) in reducing shoot and panicle damage. HCH (0.075%) -f- carbaryl (0.075%) was on par with phosphamidon (0.015%) + carbaryl (0-075%) in reducing the infestation. However, the conjunctive use of insecticides did not show superior performance as compared to their individual applications, except in the case of HCH + carbaryl in which case, the combined application was found to be superior to HCH. But this mixture was not superior to carbaryl applied alone.