Toxicity Bioassay And Control Of A168 Strain Activities Substance Against Rhizoctonia Solani

The A168 antibacterial substance and pharmaceutical compound on the toxicity of Rhizoctonia solani were tested indoor and field in this paper to explore their inhibition ability to hizoctonia solani. Using growth rate methods and field investigation, the depression effect of many single-dose and its compound against Rhizoctonia solani were tested. Finally, the best compound ratio was obtained through the combination of single-dose with high toxicity, Meanwhile, many field trials were designed to screen new control and provide a scientific basis to resistance management of rice sheath blight fungicides. The results were as follows:1 Determination of several fungicides toxicityUsing growth rate methods, the toxicity of five fungicides were assayed against Rhizoctonia solani. The results showed that the five fungicides toxicity against Rhizoctonia solani from high to low were 75% tricyclazole WP> A168 active substance> 50% carbendazim WP> 25% Jinggangmycin WP> 25% Triadimefon WP, respectively.2 The best compound ratio of several fungicidesThe A168 antibacterial substance was mixtured with 75% tricyclazole WP and 50% carbendazim WP. The synergistic inhibitory effects of fungicides compound was evaluated by experimental design of Horsfan virulence. The results indicated that the mixture of A168 antibacterial substance and 75% tricyclazole WP had a synergistic effect. The toxicity reached to 93.1% when the mixture ratio was 40:60, obviously higher than the toxicity of single-dose. In addition, the mixture of A168 antibacterial substance and 50% Jinggangmycin WP also demonstrated some synergy. The toxicity was 93.1% when the mixture ratio was 50:50. Additionally, different mixture ratio of A168 antibacterial substance and 50% Jinggangmycin WP showed depression effect of at least 75%, indicating that A168 antibacterial substance could enhance the toxicity.3 Field control effect The A168 antibacterial substance,75% tricyclazole WP,50% carbendazim WP and their mixture were detected in the field serious destroyed by Rhizoctonia solani. The results showed that the compound of A168 antibacterial substance with 75% tricyclazole WP had a good control effect on Rhizoctonia solani, whose control effect was 84.74%, significantly higher than the compound of A168 antibacterial substance with 50% carbendazim WP. Meanwhile, both of the these compound fungicides was obviously higher than their single-dose. Therefore, the control effect of the other treatment from high to low are as follows:A168 antibacterial substance> 25% Jinggangmycin WP> 50% carbendazim WP. Variance analysis showed that different treatments had a significant difference. Above all, the compound of A168 antibacterial substance with 75% tricyclazole WP, the compound of A168 antibacterial substance with 50% carbendazim WP had a most significantly difference. The A168 antibacterial substance,25% Jinggangmycin,25% carbendazim differences between the three treatment was also highly significant.