Botanical pesticides have limited persistence in field conditions because are degraded by temperature, ultraviolet light and other environmental factors. Corn plants cultivated in greenhouse were sprayed with ethyl acetate extract of Trichilia pallida at the concentration of 2%, and their leaves were offered to Spodoptera frugiperda larvae in order to evaluate the residual effect of the extract. The larval feeding began at 1, 3 and 7 days after the treatment with the extract. Two groups of larvae were evaluated: neonate and 10-day old ones. The leaves were daily replaced and after 10 days the mortality, the head capsules and the weight of larvae were evaluated. Independently of the residue age, all treatments affected larval survivorship and delayed larval development, but these effects were more pronounced for larvae fed one day treated leaves. The extract was more effective against neonate larvae than to 10 days old day larvae.
insecticide plants; fall armyworm; plant extracts
