Toxicidade de óleo de Nim para pupas e adultos de Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae)

Abstract

The objective of this work was to evaluate the effects of Nim-I-Go™ on pupae and adults of Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae). The neem-based insecticide Nim-I-Go™ was used in the following concentrations (%) in the pupae trial: 0.5; 1.0; 2.0 and 5.0; equivalent to (in mg of azadirachtin/L of water) 5 mg/L, 10 mg/L, 20 mg/L and 50 mg/L, respectively. In the larvae trial the following concentrations were used: 0.25; 0.5; 0.75; 1.0 and 2.0; equivalent to (in mg of azadirachtin/L) 2.5 mg/L, 5.0 mg/L, 7.5 mg/L, 10 mg/L and 20 mg/L, respectively. Chlorpyrifos was used as a negative control (0.48 g a.i./L) in both trials, and water as a positive control. The bioassays were carried out at 25 ± 2 o C, RH of 70 ± 10%, and 12-h of photophase. The sprayings were carried out using a Potter’s tower, ensuring the application of 1.5 ± 0.5 mg/cm2 . Survival of pupae and adults, and the effects of the insecticides on the reproductive capacity of this predator were evaluated. The total toxic effect (E) of the insecticides was calculated according to the standard methodology established by IOBC. Nim-I-Go™ was harmless to pupae and adults of C. externa. Chlorpyrifos was harmful to this natural enemy.