Toxicities of 17 Fungicides and Joint Toxicity on Walnut Root Rot Fungus

The inhibitory effect of 17 fungicides and co-toxicity between probenazole and prochloraz on walnut root rot fungus were determined by mycelium growth rate method. The results showed that probenazole, prochloraz, imazalil and thiophanatemethyl had stronger inhibitory effects among all, the strongest inhibitory effect of probenazole with EC50 of 0.092 6 mg / L.While azoxystrobin, isoprothiolane and triazolone had weakest inhibitory effect. When probenazole and prochloraz mixing ratios were 1∶3,1∶5 and 1∶7, the co-toxicity efficient(CTC) was 160.543 5,182.803 6 and 226.194 0, respectively, of which the mixture of 1∶7 was the most significant synergism.