嘧霉胺与枯草芽孢杆菌B-916协同防治梨黑斑病

Synergistic Effect of Pyrimethanil and Bacillus subtilis B-916 against Alternaria kikuchiana

室内测定28种化学药剂和枯草芽孢杆菌B-916对梨黑斑病菌的毒力,将毒力最强的化学药剂与拮抗细菌枯草芽孢杆菌B-916进行复配,探讨复配剂对梨黑斑病的室内毒力效果和田间防治效果。室内测定结果显示:28种常见化学药剂中嘧霉胺能有效抑制梨黑斑病菌菌丝生长,当嘧霉胺浓度大于或等于0.10 mg/L时,抑制率为100.00%;枯草芽孢杆菌B-916对梨黑斑病菌菌丝生长具有较强的抑制作用,抑菌圈直径达55 mm;将枯草芽孢杆菌B-916(2.00×108CFU/ml)与嘧霉胺(10 000 mg/L)复配,配比为2∶1时对病菌抑制的增效比达4.18。该复配剂稀释20倍(6.67×106CFU/ml B-916+167 mg/L嘧霉胺)对梨黑斑病的田间防治效果为58.26%,显著优于嘧霉胺(500 mg/L)和B-916(1.00×107CFU/ml)单剂。

Toxicities of 28 fungicides and Bacillus subtilis B-916 against Alternaria kikuchiana were tested in this study.The mixture of the strongest-toxicity fungicide and antagonistic bacterium B-916 was detected for its laboratory toxicity and control effect in the fields on pear black spot.The results showed that pyrimethanil in 28 fungicides could effectively inhibit the mycelia growth of A.kikuchiana with the inhibition rate of 100.00 % when the concentration of pyrimethanil in potato dextrose agar（PDA） was equal or greater than 0.10 mg/L.Bacillus subtilis strain B-916 strongly inhibited the mycelia growth of A.kikuchiana with the inhibition zone of 55 mm.The synergistic ratio of mixture of Bacillus subtilis B-916（2×108 CFU/ml）and pyrimethanil（10 000 mg/L）with the ratio of 2∶1 was 4.18,and the control effect of this mixture diluted 20 fold on pear black spot was 58.26%,which was better than that of pyrimethanil（500 mg/L） or Bacillus subtilis B-916（1×107 CFU/ ml）applied alone.