Efeito do extrato acetato de etila de Trichilia pallida Swartz (Meliaceae) no desenvolvimento e sobrevivência da lagarta-do-cartucho

The effect of different concentrations (mass/volume) of ethyl acetate extract from leaves and twigs of Trichilia pallida on Spodoptera frugiperda (J.E. Smith) was evaluated under laboratory conditions. The activity of this extract was investigated by dipping corn leaves in solutions with extract concentrations of 0.0001%; 0.0008%; 0.006%; 0.05%; 0.4% and 3%, and offered to just-born and 10-day old larvae. The evaluated parameters were length and viability of larval and pupal stages. The estimated letal concentration LC50 for seven-day old larvae was 0.048%. Based on the results, it was concluded that 100% of larval mortality was achieved at concentrations equal or higher than 0.05%; the survival and development of S. frugiperda was affected at concentrations of 0.006% and no effect was observed at concentrations equal or lower than 0.0008%; the extract was more effective when treated leaves were offered to just-born larvae than to 10-day old larvae.