Mortality, development and morphological effects of carbaryl and acephate on Podisus maculiventris (SAY)

Successful incorporation of Podisus maculiventris (Say) in an integrated pest management program requires testing of recommended insecticides for selectivity to the predator. Acephate (Orthene 75 S) at 0.59 g (AI)/1 and 3.0 g (AI)/1 and carbaryl (Sevin 50 WP) at 1.5 g (AI)/1 and 7.5 g (AI)/1 were ingested by Epilachna varivestis Mulsant larvae from treated snapbean foliage. Second, third, fourth, and fifth instar P. maculiventris nymphs were reared on the pesticide treated larvae to determine mortality and development times of nymphs and morphology of adults. Both concentrations of acephate, as injested by prey subsequently fed to predators, induced significantly greater mortality (P < 0.05) than the carbaryl. There was no significant difference in mortality of nymphs in carbaryl and control treatments. Developmental times for nymphs ingesting both toxins at each formulation were significantly longer (P < 0.05) than nymphs in the control treatment. Adults in control treatments were somewhat larger than adults from pesticide treatments. Mortality of nymphs in carbaryl treatments was not significantly different from those in the control treatments thus making it a candidate for incorporation in an integrated pest management program.