Effect of insecticides on parasitism by egg parasitoids of the rice yellow stem borer, Scirpophaga incertulas
P Vennila, G Sridevi and AP Padmakumari
Greenhouse studies were undertaken to study the effect of commonly used insecticides in rice against the egg parasitoids of yellow stem borer. Our study observed that Tetrastichus schoenobii Ferriere is an efficient egg parasitoid on rice yellow stem borer, Scirpophaga incertulas (Walker) followed by Telenomus dignus Gahan at Rajendranagar, India. The results revealed that egg mass parasitization was not effected in chlorantraniliprole and spinosad treatments. Among the two species, insecticide treatment of egg mass had less effect on Tetrastichus as compared to Telenomus. Parasitization by T. dingus was observed only in fipronil and cartap hydrochloride treated egg mass and was similar to the untreated control which indicated that they were safer to this parasitoid. The results can have an implication in the choice of insecticides that can be used for control of the rice pests.