Feeding stimulants (phagostimulants) increase the food uptake by the host insect larvae and thereby play a vital role in enhancing overall activity of insect viruses formulated as biopesticides. A local strain of granulovirus of Pieris brassicae (PbGV), a serious pest of cole crops worldwide, has shown potential as a biopesticide against this pest and with slight increase in its efficacy can be used successfully as a promising biocontrol agent in integrated pest management (IPM) programs of the pest. The addition of phagostimulants may enhance the efficacy but so far no specific phagostimulant for PbGV has been reported. In the present studies, some reported phagostimulants for insect viruses were tested for their impact on food utilization by host larvae and efficacy of the virus. The specified concentration of virus isolate was mixed with phagostimulants and laboratory studies were conducted to uncover their effect on consumption index (CI) and larval mortality. The studies revealed that phagostimulants, viz. boric acid and crude sugar, when mixed with PbGV, showed highest CI and larval mortality. Consumption index of 1.34, 1.49 and 1.43 mg/mg/day and corresponding larval mortality of 32.9%, 45.8% and 34.2% were recorded with the addition of 0.5% and 1% boric acid and 2% crude sugar, respectively, in PbGV. The leaf extracts of cabbage, cauliflower and broccoli at both the concentrations (1% and 2%) also enhanced the CI but were comparatively less effective than the boric acid and crude sugar. Field evaluation of PbGValone and in combination with phagostimulants carried out at two geographically isolated locations, viz. Palampur (subtropical) and Sangla (temperate) on three cole crops (cabbage, cauliflower and broccoli) showed that boric acid was the most promising candidate for enhancing the PbGV efficacy under field conditions, followed by crude sugar.