Toxicidade, deterrência e repelência de extratos aquosos de Cabralea canjerana ssp. polytricha (a. juss.) penn. (Meliaceae) sobre o curuquerê-da-couve ascia monuste orseis (godart) (Lepidoptera: pieridae)

摘要

The toxicity, deterrence and repellence of aqueous extracts of seeds, leaves and fruits of Cabralea canjerana ssp. polytricha (Meliaceae) on the cabbage caterpillar, Ascia monuste orseis (Lepidoptera), were evaluated in laboratory. Aqueous extract of 3, 5 and 10% were obtained by infusion of dried and pulverized biological material in distilled water, filtered after 24h. Within 48h after preparation, cabbage leaves were immersed in the extracts or in distilled water and used in tests to verify differences on larval survival and on larval life-time between control and treatments. Extract repellency and deterrence were evaluated in free and non-free-choice tests for treated and non-treated cabbage leaves, by comparisons among the consumed area and the number of larvae per leaf portion. It was observed 100% larval mortality in the treatments in contrast to the 87% survival rate in the control. Larvae fed on treated cabbage leaves did not live as much as the control ones. Seed extracts, contrary to leaf and fruit extracts, had a repellent effect but it was not sufficiently intense to avoid leaf consumption. It was observed a reduction on larval leaf consumption in all free-choice treatments using 10% extracts. When the larvae did not have the option to consume non-treated leaves, they fed on treated leaves, but consuming smaller portions, especially when 10 and 5% extracts were used.