LABORATORY STUDIES ON EFFECT OF PESTICIDE S ON ENTOMOPATHOGENIC FUNGUS, VERTICILLIUM-LECANII

The effect of fungicides and bactericides on Verticillium lecanii was evaluated both on agar plates, and on larvae of the greenhouse whitefl y, Trialeurodes vaporariorum in the laboratory: Polyoxin, procymidone: sulfur; mepronil and copper hydroxide were harmless to conidial germi nation of the fungus on agar plates and showed no effect on the mortal ity of the insect when larvae were inoculated with a conidial suspensi on mixed with each. Triflumizole, dithianon, chinomethionat and zineb were highly toxic to conidial germination of the fungus on agar plates . However, when larvae were inoculated with conidial suspension mixed with each at a concentration sufficient to inhibit conidial germinatio n, larvae were killed at percentages of 39%, 54%, 72% and 100%, respec tively. Reduction of larval mortality by treatment with triflumizole w as not observed 48 h or more after inoculation. Polyoxin, sulfur, mepr onil, procymidone, copper hydroxide, dithianon and zineb were harmless to mycelial growth producing conidia on the surface of larvae killed by the fungus, while triflumizole, chinomethionat, anilazine and benom yl were toxic to mycelial growth.