Bio-efficacy and phytotoxicity of new combination of mairm-23 (Pymetrozine 29.2% w/w + Dinotefuran 11.7% w/w WDG) against brown plant hopper, Nilaparvata lugens (Stal.) on rice

Bio-efficacy and phytotoxicity of seven insecticides including Pymetrozine 29.2 + Dinotefuran 11.7 WDG (mairm-23) @ 600, 500 and 400 g/ha, Pymetrozine 50 WG @ 300 g/ha, Dinotefuran 20 SG @ 200 g/ ha and Buprofezin 15 + Acephate 35 WP @ 1250 ml/ha were evaluated against brown plant hopper (BPH) in rice along with control. The BPH population pre count treatment was non significant in both seasons. Mairm-23 @ 600 and 500 g/ha and Pymetrozine @ 300 g/ha were recorded significantly lower BPH population followed by next best treatments Mairm-23 @ 400 g/ha, Diinotefuran 20 SG @ 200 g/ha and Buprofezin 15 and Acephate 35 WP @ 1,250 ml/ha as compared to untreated control at 1,3,5,7 and 10 days after first spray. The similar trend was observed at second and third sprayings in both the seasons. The maximum per cent reduction of BPH over the control was exhibited by mairm-23 @ 600 and 500 g/ha followed by pymetrozine 50 WG @ 300 g/ha. The high grain yields recorded on mairm-23 @ 600 g/ha and 500 g/ha were on par with each other and followed by rest of the treatments. Low cost benefit ratio was observed on mairm-23 @ 500 g/ha. No phytotoxicity symptoms and no adverse effects on natural enemies were noticed in application of single and double dosages of mairm-23 @ 500 g/ha. Mairm-23 @ 500 g/ha was effective in controlling BPH population and gave gain higher grain yield, and showed lower cost benefit ratio with no phytotoxicity symptoms and no adverse effects on natural enemies.