Efficacy of Insecticides Against Yellow Stem Borer (Scirpophaga incertulas Walker) and Rice Leaf Folder (Cnaphaocrocis medinalis Guenee) and Their Impact on Natural Enemies in Rice Ecosystem
Rituraj Saikia *
AAU-Assam Rice Research Institute, Titabor, Jorhat, Assam, India.
Sanjib Ranjan Borah
AAU-Assam Rice Research Institute, Titabor, Jorhat, Assam, India.
Milon Jyoti Konwar
AAU-Assam Rice Research Institute, Titabor, Jorhat, Assam, India.
Arunima Bharali
AAU-Assam Rice Research Institute, Titabor, Jorhat, Assam, India.
Safiqul Hussain
AAU-Assam Rice Research Institute, Titabor, Jorhat, Assam, India.
*Author to whom correspondence should be addressed.
Abstract
The experiment was conducted at AAU-Assam Rice Research Institute, Titabor to test the efficacy of some insecticides against yellow stem borer and rice leaf folder. Out of 8 tested insecticides, Chlorantraniliprole 18.5 SC showed the best result in minimizing yellow stem borer and rice leaf folder infestation. The lowest infestation percentage of yellow stem borer (2.10%) was observed on Chlorantraniliprole 18.5 SC treated plots followed by treatment with Chlorantraniliprole 10% + Lambda Cyhalothrin 5% ZC (2.33 %) at 7 DAT. Similarly, white ear head (0.33%) was also recorded as the lowest on Chlorantraniliprole 18.5 SC treated plots. Chlorantraniliprole 18.5 SC recorded the lowest infestation percentage of rice leaf folder at 7 DAT (3.40 %) and 14 DAT (3.53 %) followed by Chlorantraniliprole 10% + Lambda Cyhalothrin 5% ZC. While, the highest number of spiders and coccinellids were recorded in Chlorantraniliprole 0.4GR (2.43 spider/plant and 1.33 coccinellids/plant) followed by Thiamethoxam 25WG (2.13 spiders/plant and 1.10 coccinellids/plant). In terms of yield, Chlorantraniliprole 18.5 SC was found to be the best insecticide which provided the highest yield of 5.83t/ha among all the tested insecticides.
Keywords: Efficacy, insecticides, rice, natural enemies, yellow stem borer, leaf folder