Bioassays were conducted to investigate the effect of milk powder additives on the performance of a heliothis nucleopolyhedrovirus (Gemstar) and Bacillus thuringiensis (Dipel SC) on mungbeans and cotton. Larval mortality increased when the calf feeding supplement, Denkavit , was added at I kg/ha to both Gemstar and Dipel SC. Other powder additives and a liquid formulation, Amino Feed, were mostly equivalent to Denkavit. While Envirofeast and Pred Feed would not be considered for use solely as an additive to Gemstar or Dipel SC, the data indicate that improved performance from Gemstar could be expected if added to these food sprays. The mode of action of these additives has not been determined