Impact of Certain Insecticides on Pupa of Egg Parasitoid, <I>Trichogramma confusum</I> Viggiani (Hymenoptera: Trichogrammatidae)

Abstract

Egg parasitoid Trichogramma confusum Viggiani (Hymenoptera: Trichogrammatidae) is an important natural enemy, commonly used to control sugarcane stemborers worldwide. Occasionally, insecticides have to be applied to reduce sugarcane insect pests especially when the outbreak occurred. However, the available information of insecticides that are high efficiency to control sugarcane insect pests but are safe to this egg parasitoid is very insufficient. Therefore, the impact of 8 common insecticides: deltamethrin, lambda cyhalothrin, cypermethrin, chlorpyrifos, carbosulfan, carbaryl, fenobucarb and fipronil on pupa of egg parasitoid, T. confusum, was studied in order to find the insecticides that are efficient to control the sugarcane insect pest and safe to this outstanding parasitoid. The study was conducted at the National Biological Control Research Center (NBCRC), lower northern regional office based on completely randomized design with 5 replications and 100 insect pupa in each experimental unit. The insecticides were applied by direct spraying and dipping methods. The quality and efficiency of T. confusum survivors were determined. Results from both application methods showed that most of pyrethroid insecticides affected T. confusum pupa less than the others. Deltamethrin was the least toxic in this group, followed by cypermethrin and lambda-cyhalothrin, respectively. Chlorpyrifos and carbaryl were significantly high toxicity.