Browsing by Author "G K, RAME GOWDA"
Now showing 1 - 1 of 1
Results Per Page
Sort Options
ThesisItem Open Access STUDIES ON RESISTANCE TO INSECTICIDES IN Spodoptera litura (Fabricius) ON GROUNDNUT(University of Agricultural Sciences, Dharwad, 1999) G K, RAME GOWDA; BASAVANA GOUD, KIrrespective of the insecticides, maximum loss of sensitivity was observed in Manvi strain (39.09% mortality) followed by Hospet (68.48%) strain which represented high pesticide usage areas. Whereas strains from low pesticide pressured areas were highly sensitive with more than 80.00 percent larval mortality. Irrespective of the strains, maximum loss of sensitivity was for monocrotophos (65.56%) followed by carbaryl (68.89%). Resistance to monocrotophos was highest (8.48 folds) followed by endosulfan (3.30), quinalphos (2.00) and cypermethrin (1.61). Higher levels of resistance, irrespective of the insecticides was noticed from medium (3.80-9.79) and high (4.08- 5.07) pesticide usage areas. The dynamics of resistance to monocrotophos was static from September to February (33.1 2 - 37.66 folds) except during October (44.99). Later the resistance build-up was fast, reaching a peak of 93.1 1 folds during April. Sesame oil, honge oil and pundi oil exhibited higher synergistic action with synergistic ratios of 14.32, 11.97 and 10.85 for cypermethrin and 3.32, 2.84 and 3.41 for monocrotophos, respectively. The pathogenisity of microbial agents, Viz., Spodoptera litura nuclear polyhedrosis virus. Bacillus thuringiensis sub sp. kurstaki and Nomuraea rileyi to susceptible and resistant strains of S.litura remained same. B.thuringiensis and SI NPV were more effective against resistant populations of S.litura by causing 74 and 72 percent larval mortality, respectively compared to quinalphos (60%). N. rileyi was least effective with 34.00 percent larval mortality. Among the new molecules of insecticides tested, polytrin C-44, profenofos and carbosulfan were highly effective causing more than 96 percent larval mortality; whereas cypermethrin was totally ineffective without causing any mortality followed by monocrotophos which caused only 20.00 percent mortality.