Nine fungicides and 14 insecticides and acaracides were tested in vitro on various isolates of the entomopathogenic fungi,Beauveria bassiana,Verticillium lecaniiandVerticilliumsp. Two techniques were employed: for Verticillium, a “poisoned-bait” method, showing growth inhibition; forB. bassiana, a poisoned-agar disc method, showing inhibition of conidial germination.All chemicals except white summer oil caused some inhibition to Verticillium growth at 10−4of the recommended dosages for use.Great variations in sensitivity toward a particular fungicide (e.g., captan, copper oxychloride, dinocap, binapacryl) were found among isolates of the same fungal species of both genera, and were also observed with some insecticides (e.g., trichlorfon and narrow-range paraffinic oil onVerticillium).Among the fungicides, benomyl (methyl 1-[butylcarbamyl]-2-benzimidazole carbamate) and maneb caused the greatest inhibition of all isolates of both genera at recommended dosages and at 10−1concn, indicating that their use in field or grove would endanger the fungi. At recommended dosages, copper oxychloride and dinocap were the most innocuous to all the fungi (with the exception of 1 isolate ofB. bassiana). Binapacryl had no effect on spore germination ofB. bassianabut moderately inhibited growth of most isolates ofVerticilliumspp. Daconil 2787™ (tetrachloroisophthalo-nitrite) proved moderately fungitoxic toVerticilliumand less so toB. bassiana.Among insecticides, sodium fluorosilicate, dichlorvos, and chloropyrifos at recommended dosages were strongly inhibitory to growth ofVerticiliumspp., but only sodium fluorosilicate inhibited germination ofB. bassiana.