Comparative biology and fertility parameters of two spotted spider mite, Tetranychus urticae Koch. on different grapevine varieties

The influence of the four grapevine varieties 'Thompson Seedless', 'Manjri Naveen', 'Gulabi' and 'Bangalore Blue' on fitness, development and reproductive characteristics of the two spotted spider mite, Tetranychus urticae was studied. The biology of two spotted spider mites consisted of egg, larvae, protonymph, deutonymph and adult stages. The total duration from egg to adult was found to be the least in 'Thompson Seedless' (16.2 days) followed by ''Manjri Naveen' (17.2 days), 'Gulabi' (17.2 days) and maximum in 'Bangalore Blue' (32.2 days). The survival rate of life stages of mites was found to be lower in 'Bangalore Blue'. The higher values of net reproductive rate, intrinsic rate of increase, finite rate of increase the shortest mean generation time was observed in 'Thompson Seedless' followed by 'Gulabi', 'Manjri Naveen' and 'Bangalore Blue'. The results suggested that 'Thompson Seedless' was the most suitable cultivar with higher survival rate of life stages of mites, shortest development period, higher value intrinsic rate of increase and fecundity whereas 'Bangalore Blue' was the least suitable cultivar because of the lowest intrinsic rate of increase, longest development period, lower survival rate of life stages of mites