The aim of this study was to evaluate the effects of physic nut and neem oil on the hatching of caterpillars of Diatraea saccharalis (Fabr., 1794). Tests were conducted in acclimatized chambers at 25 ± 2° C, RH 70 ± 10% and photophase of 12h. The treatments were: distilled water (control), aqueous solution of physic nut oil at 3%; aqueous solution of neem oil at 3%, and aqueous solution of physic nut and neem oil, both at 3%. A total of 250 eggs from D. saccharalis up to 24 hours of age were used for each treatment. Each egg mass containing 50 eggs, constituting one repetition, was immersed three times, for one second, in the respective treatments. Then the eggs were distributed in Petri dishes (5 cm diameter) containing filter paper moistened with distilled water at the bottom to prevent drying of the egg mass. Evaluations were made of the embryonic period and the percentage of hatched larvae of D. saccharalis. Differences were found that indicate that the vegetable oils had a toxic effect on the hatching of sugarcane borer larvae. In the treatment with neem oil only 42.4% of the eggs hatched. In the treatment with physic nut + neem oil 70% of the eggs hatched, and in the treatment with physic nut oil 60% of the eggs hatched. An increase in the embryonic period was also observed, particularly in the treatment with physic nut oil (7.09 days). It can be inferred that the oils of neem and physic nut affected the hatching of D. saccharalis eggs, with an insecticide effect.
Sugarcane borer; natural insecticide; insecticidal plants