Laboratory and Field Evaluation of Insecticides Against Spodoptera littoralis Larvae1

Abstract

Twelve insecticides used at one or more concentrations and different formulations of the same insecticide were evaluated in the field in the fall of 1969 for the control of larvae of Spodoptera littoralis (Boisduval) on lucerne. A bioassay in which all field-tested insecticides were included was performed in the laboratory to determine their effectiveness against 3rd- and 5th-stage Spodoptera larvae. More than 90% mortality of both instars was obtained with Cyolane® (cyclic ethylene (diethoxyphosphinyl) dithioimidocarbonate) 25% EC applied at the rate of 1.49 kg and 1.11 kg active ingredient/ha. Monocrotophos 40% EC at 1.48 kg AI/ha gave 90% control of 3rd instar and 80% control of the 5th-instar larvae. Field mortality, in which no separation of instars was attempted, was assessed 5 days following treatment. More than 90% mortality of the mixed instar population was obtained with monocrotophos 60% EC at 1.47 kg, Cyolane 25% EC at 0.78 kg, 1.49 kg, and 1.11 kg, and Gardona® (2-chloro-l-(2,4,5-triehlorophenyl) vinyl dimethyl phosphate) 75% wp at 1.46 kg/ha. Monocrotophos 40% EC rate at 1.11 kg gave 88.5% control.