Preliminary Study On The Compatibility Between Metarhizium Anisopliae And Chemical Pesticides

Metarhizium anisopliae, one of the most important entomogenous fungus, is used to infect a wide range of pests. In this paper, effect of chemical insecticide on conidial germination, colony and sporulation quantity of M. anisopliae were determinated. Effect of chemical insecticide on activity level of extracellular protease and chitinase of M. anisopliae were also detected. It would clarificate the effect of chemical insecticide on M. anisopliae and its synergism to pests. This work could make good use of the advantages of M. anisopliae and chemical insecticide. Meanwhile, effect of chemical germicide on conidial germination of M. anisopliae was researched. This will play a guiding role in the effective use of M. anisopliae. The main results are as follows.All the 10 chemical insecticides tested had influence on M. anisopliae. The inhibition was decreased with the decrease concentration. Different insecticides had different influence on conidial germination, colony and sporulation quantity of M. anisopliae. Effect of Bifenthrin and Cypermethrin on conidial germination of most strains was small. Avermectin had small effect on conidial germination of strains Ma201,Ma203,Ma205. Abamectin chlorbenzuron had small effect on strain Ma208. Abamectin chlorbenzuron, Methomyl and Phoxim had little influence on colony. Low concentration of these three insecticides had negative inhibition. This indicated that these three insecticides were possible to promote colony growth. In low concentration, most insecticides had negative inhibition on sporulation quantity, such as Malathion, Bifenthrin, Trichlorfon, Methomyl, Avermectin and Tebufenozide. It revealed that there was possible that insecticides of low concentration could promote sporulation of M. anisopliae.Besides, different strains had different sensitivity to the same insecticide. Conidia of strain Ma208 had high sensitivity to most insecticides, but low to Cypermethrin. Insecticides had significantly influence on colony of strain Ma336, but little influence on other strains. Insecticides had great effect on sporulation quantity of strains Ma202 and Ma103, but little on other strains.Chemical insecticides had great effect on chitinase activity of M. anisopliae. Chitinase activity of most strains decreased after treated by insecticides, especially the three strains (Ma103,Ma337,Ma208) which had high activity decreased observably. But strain Ma205 did not change significantly. Chitinase activity of strains Ma202,Ma207 increased slightly.Effect of chemical insectcides on protease activity of M. anisopliae was great. Protease activity of most strains decreased after treated by insecticides. But strains Ma201 and Ma203 had no obvious change. Protease activity of strains Ma202,Ma207 increased a little.Different chemical germicides had different inhibition on M. anisopliae and the inhibition was decreased with the decrease of concentration. Myclobutanil and Mancozeb showed minimum inhibition on M. anisopliae. The germination rates of M. anisopliae were high after treated by these two chemical germicides. This showed that Myclobutanil and Mancozeb had little influence on M. anisopliae. The other chemical germicides, especially Chlorothalonil and Thiophanate methyl, had significantly inhibition on M. anisopliae, which reached 100%. Different strains exhibited different sensitivity towards chemical germicide.