Management of mustard aphid, Lipaphis erysimi (kaltenbach) in rapeseed- mustard with botanicals and varietal resistance

Field studies were carried out for two consecutive rabi seasons (2005–06 and 2006–07) to screen certain rapeseed-mustard varieties for their resistance against mustard aphid, Lipaphis erysimi and to evaluate the bioefficacy of certain botanical and microbial insecticides. Their impact on predators, pollinators and crop yield were also evaluated. Among the sixteen varieties/genotypes tested, TH-0101 and Potsangbam yella possessed high level resistance to mustard aphid. Metasystox was found to be the most effective, followed by neem products, i.e., Neemazal, Nimbecidine and Econeem. Whereas, microbial Verticel was least effective in controlling mustard aphid, but all the insecticidal treatments were superior to control. The population of predator, Coccinella septempunctata was found higher in plots treated with Verticel (2.01 beetles/plant), followed by Cal-MB(1.87 beetles/plant). Whereas, metasystox was found to be highly toxic to beetles (0.85 beetles/plant). The population of bees was higher in the plots treated with Cal-MB (2.53/10 plants/5 minutes) followed by Verticel (2.38/10 plants/5 minutes). The most toxic effect to bees was found in metasystox with minimum population (0.61 bees/10 plants/5 minutes). Highest seed yield (16.10q/ha) was recorded in the plots treated with metasystox, and it was found to be the most economic treatment with costbenefit ratio of 1:7.34.