Estimation of the population of parasitoids associated with lac insect, Kerria lacca Kerr. on the basis of biometrical characters

Relationships between density of lac insect, Kerria lacca Kerr., number of shoots with lac and length of lac encrustation on each shoot with incidence of three major parasitoids associated with lac were worked out. The regression equations developed for estimating the population of these parasitoid. showed that 90–120 days after the start of lac culture, about 64, 50 and 30 per cent variation in the population of Tetrastichus perpureus (Cam.), Tachardiaephagus tachardiae (How.), and Parechthrodryinus clavicornis (Cam.), respectively could be explained by density of lac insect on shoot, number of shoots with lac, and length of enrustation on shoot. After 121–150 days from the start of culture, these biometrical characters explained 55 per cent variation in the population of T. perpureus according to the regression equation developed. Out of 3 characters, the density of lac insect alone explained significant variation in the population of its parasitoids.