Indian Journal of Entomology

Whitefly, Bemisia tabaci (Gennadius.) has drawn global attention in recent past with its wide distribution across the world as it causes severe damage to crops directly by sucking the plant sap and indirectly as vector of several viral diseases. This pest is considered as a species complex and Asia represents the largest diversity with the distribution of about 16 out of 35 genetic groups recorded so far. Investigations were carried out on kinetics of a key digestive enzyme, á-amylase in adults of isogenic female lines of B. tabaci genetic groups Asia I and Asia II-1. Asia I has shown the higher specific activity of 0.267±0.007 μmol/ml/mg compared to that of 0.209±0.009 μmol/ml/mg in Asia II-1. However, kinetics of á-amylases revealed the high affinity of this enzyme in Asia II-1 with the least K_m value of 0.03372±0.001 compared to that of 0.0353 ±0.002 in Asia I genetic group. Highest enzyme activities were recorded at 35° C in both the genetic groups of B. tabaci. Kinetics study of metabolically important digestive enzymes would improve our understanding on the metabolic capabilities of B. tabaci species complex.