Evaluation of efficacy of acetamiprid (Pride 20SP) against whitefly, Bemisia tabaci (Genn.) on American cotton

摘要

Three dosages of acetamiprid (Pride 20 SP) i.e @ 100, 150 and 200g/ha were compared with the recommended dosages of oxydemeton methyal (Metasystox 25EC) @ 750 ml/ha, triazophos (Hostathion 40 EC) @ 1500 ml/ha and ethion (Phosphite 50 EC) @ 2000 ml/hafor the control of whitefly, Bemisia tabaci (Genn.) on American cotton during kharif, 2003. Pride 20SP @ 150 and 200 g/ha, being on a par with each other proved significantly better for the control of B. tabaci upto 7 days after spray. Maximum reductionin B. tabaci population (-50.00 to -77.67%) occurred only one day after spray. After that its population showed an increasing trend though remained at a low level than that observed before spray in all the treatments, except Metasystox 25 EC where it started resurging 3 days after spray. A decrease of 38.16, 34.83, 19.13, 9.89 and 9.25 per cent in B. tabaci population was observed 7 days after spray in treatments with Pride 20 SP @ 200g, Pride 20 SP @ 150g, Hostathion 40 EC @ 1500 ml, Phosmite 50 EC @ 2000 ml and Pride 20 SP @ 100g/ha, respectively. However, an increase of 55.38 and 71.25 per cent in its population was observed 7 days after spray in treatments with Metasystox 25 EC @ 750 ml/ha and control, respectively.