Thumbnail Image

Thesis

Browse

20101
Reset filters
Subject: Entomology × Author: Amit Punj × Start date: 1968 × Thesis Type: M.Sc ×
Reset filters

Search Results

Now showing 1 - 1 of 1
  • Thumbnail Image
    ThesisItemOpen Access
    TOXICITY OF DIFFERENT INSECTICIDES AGAINST COTTON MEALY BUG, Phenacoccus solenopsis Tinsley
    (PAU Ludhiana, 2010) Amit Punj; A. K., Dhawan
    The studies on the evaluation of LC50 of insecticides against mealy bug, Phenacoccus solenopsis population collected from cotton belt during vegetative, flowering and maturity phase were conducted at Entomological Farm, PAU, Ludhiana. The new molecule, spirotetramat was found to be most toxic to first instar, third instar nymphs and adult females. Among the conventional insecticides, profenophos and thiodicarb was proved to be the most toxic. The order of toxicity was spirotetramat > clothianidin > profenophos > thiodicarb > buprofezin > chlorpyriphos > acephate. In another experiment, the persistence of different insecticides at recommended concentrations against first instar, third instar nymphs and adult females was estimated. Based on the index of persistence toxicity, the order of effectiveness for the first instar nymphs of mealy bug was profenophos (645.40) > thiodicarb (619.60) > buprofezin (572.52) > spirotetramat (430.00) > acephate (400.17) > clothianidin (376.83) > chlorpyriphos (330.17). Similarly, for third instar nymphs the order of effectiveness was profenophos (589.18) > thiodicarb (562.93) > buprofezin (548.76) > spirotetramat (395.01) > acephate (384.18) > clothianidin (359.24) > chlorpyriphos (314.53). Similarly, for the adult females the order of effectiveness was profenophos (523.23) > buprofezin (478.77) > thiodicarb (435.13) > spirotetramat (330.10) > acephate (305.00) > clothianidin (290.34) > chlorpyriphos (260.19). The third experiment was conducted to study the effect of host of mealy bug like bitterweed, cocklebur and carpet weed on the efficacy of promising insecticides. Based on LC50 values, profenophos was found to be extremely toxic to first instar, third instar nymphs and adult females of mealy bug on the above mentioned weed hosts in comparison to thiodicarb.