Influence of oxidyzing enzymes in host plant resistance to cotton mealy bugs (Phenococcus solenopsis Tinsley)

A laboratory investigation was conducted to find out the role of oxidizing enzymes in defense mechanism of cotton cultivars against mealy bugs in Insect Biotechnology Laboratory of Department of Agricultural Entomology, Dr. P. D. K. V., Akola during 2008- 09. Quantitative and qualitative studies were undertaken for estimation of oxidizing enzymes like superoxide dismutase, polyphenol oxidase, polyphenol peroxidase and catalase from different cotton cultivars. CAHH-231 (Pigmented hybrid) recorded higher activity of polyphenol oxidase (0.95 unit/mg protein/min) and polyphenol peroxidase (0.87 unit/mg protein/min). Catalase activity was found higher in susceptible cultivars. PKV-Rajat showed highest SOD activity (2.84 unit/mg) followed by Bunny-Bt. Polyphenol oxidase, polyphenol peroxidase and catalase activities were found higher in Bunny-Bt and CAHH-231 (Pigmented hybrid) which were susceptible to the sucking pests. The study will be helpful in understanding the biochemical basis of mealy bug resistance in cotton. The outcome of the present investigation will act as stepping stone to develop mealy bug resistant cotton variety.