Indian Journal of Entomology

Effect of high temperature on the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and peroxidases (POD) in the third instar of Phenacoccus solenopsis was studied under laboratory condition. Temperature influences the level of antioxidant enzymes with exposure to high temperature (40°C). There was a marked rise in catalase activity and the maximum activity (0.399 nmol/ min/ mg) was observed after 6 hr in Bhatinda population. Irrespective of the population, the activity of peroxidase was positively correlated with time of exposure, and maximum activity was observed in Sri Ganganagar (0.218 nmol/ min/ mg) population at 6 hr of exposure. Within the 3 hr of exposure the maximum activity of SOD (0.127 µM/ min /mg) was observed in Rajkot and at 4 hr (0.060± 0.019 µM/ min /mg) in Sri Ganganagar populations. With further increase in the period of exposure, significant reduction in the activity of SOD was observed, and it was maximum in Guntur populations (0.218 µM/ min/ mg) at 6 hr of exposure. Thus, the findings suggest that the exposure of mealybug to high temperature induce oxidative stress in P. solenopsis. In all the population high temperature stress induces the activity of antioxidant enzymes to overcome the oxidative cell damage in mealy bug.