| To prevent or delay the Tobacco Tibia in the formation of metalaxyl resistance, and to achieve rational and effective use of pesticides, reduce the dosage, lower production costs, reducing pesticide residue of tobacco leaf and improve the safety of pesticides to extend the service life of purpose. This article was about metalaxyl resistance level survey in Yunnan Province, a situation of resistance was understood, tobacco black shank resistant bacteria to metalaxyl and the causes and formation mechanism of resistance management techniques were explored, and formulate measures was studied .The results are as follows:1, 57 strains of phytophthora nicotianae were isolated in Yunnan Province , and the isolation rate was 42.22 %.2, The metalaxyl resistance level was detected for the 57 strains. The EC50 values different strains Metalaxyl were among 0.0129～1.6307μg/ml, there is great difference of the level of metalaxyl resistance between different Phytophthora nicotianae strains;3, The strains was isolated from the treatment plant with metalaxyl. The metalaxyl resistance of these strains were determend , the results showed that strains resistant was positively correlated with the frequency of application, concentration and application of metalaxyl.4, 280 strains were isolated that had antagonistic activity to phytophthora nicotianae. 12 antagonistic bacteria showed inhibit the effectiveness to tobacco black shank with the greenhouse test. The antagonism inhibit bacteria were test to contrl tobacco black shank with field plot trial in Jiangchuan County.and Mengzi County. The control effects of GP13, HK282, HJ01912, B254 were 71.84%, 58.82%, 73.80%, 49.96% respectively.5, resistance management showed evident result with control effect of 63.2%～65.2% by 266.7htm~2 production apllication. |
