Relative changes in the virulence and infectivity of the nuclear polyhedrosis virus in relation to the dietary habit of Helicoverpa armigera Hübner (Lep., Noctuidae)

The implications of the dietary habit of Helicoverpa armigera on the virulence and infectivity of its nuclear polyhedrosis virus were examined in the laboratory by conducting three bioassays involving six different food regimes (chickpea, tomato, redgram, cotton, bhendi, artificial diet). Irrespective of the combination of food rations a significantly lower percentage mortality and higher time taken to kill the larvae were observed in cotton-fed and dosed larval groups over the others. Correlation and regression analysis was also found to be significant between biochemical factors and percentage mortality. A negative correlation between percentage mortality and biochemical factors like foliar pH, phenols, tannins and protein binding capacity and positive correlations between percentage mortality and gut passage time were observed.