Journal of Agricultural Science and Food Research
Open Access

Abstract

Toxicity and Residual Activity of a Commercial Formulation of Oil from Neem, Azadirachta indica A. Juss. (Meliaceae), in the Embryonic Development of Diatraea saccharalis F. (Lepidoptera: Crambidae)

Camila Vieira da Silva, Larissa Carla Lauer Schneider and Hélio Conte

The effects of a commercial formulation of oil from neem, Azadirachta indica A. Juss (Meliaceae), on the eggs of sugarcane borer Diatraea saccharalis F.,1794 (Lepidoptera: Crambidae), at different stages of its embryonicdevelopment were investigated. To evaluate the ovicidal activity of the oil, eggs were sprayed with the product at concentrations of 0.1%, 0.3%, 0.5%, 1.0% and 2.0% at 1, 2, 3, 4, 5 and 6 days after day were laid. Controls were sprayed with distilled water. The neem oil was toxic to eggs, mainly when applied to 2-, 3-, 4- and 5-daysold eggs. The percentage of viability reduction was 31-99%. Higher levels of caterpillar eclosion were obtained in eggs treated with neem oil at older ages. However, the resulting caterpillars had fatal morphological anomalies, except those exposed to 0.1% neem oil. Neem oil is highly toxic when sprayed on D. saccharalis eggs, as demonstrated by severely reduced hatching, increased mortality of hatched caterpillars, impaired embryonic development, and residual activity in the production of new individuals. Therefore, neem oil may be a promising  agent against the sugarcane borer, during the stage in which penetrates the stalk, causing heavy damage to the sugar-cane crop.