Control Effects of Bacillus subtilis DJ-6 and Pyraclostrobin Alone and in Combination Against Fusarium oxysporum

枯草芽孢杆菌DJ-6与吡唑醚菌酯及其混配对草莓枯萎病的室内抑菌活性与田间促生防病效果（英文）

[Objective] This study was conducted to screen a synergistic biological fungicide complex to control Fusarium wilt, reducing the use of chemical pesticides. [Method] The inhibitory effects of Bacil us subtilis DJ-6 and pyraclostrobin alone or in combination at five ratios against Fusarium oxysporum were detected by mea-suring mycelium growth rate in laboratory tests. The growth promotion and disease control effect of combined or single use of 20% pyraclostrobin and 2 ×1011 cfu/g B. subtilis DJ-6 WP at 1∶1 000, 1∶2 000 and 1∶3 000 dilutions were detected in field trials. [Result] The EC50 values of combined use of B. subtilis DJ-6 and pyra-clostrobin at ratios of 1∶1, 1∶2, 1∶3, 1∶4 and 1∶5 against F. oxysporum were 5.311 5, 4.008 6, 3.570 6, 3.350 9 and 3.218 9 μg/ml, with the synergistic ratios （SR） of 2.28, 1.77, 1.53, 1.64, 1.11, among which the synergetic effect at 1∶1 was the best. The fungicidal activity of pyraclostrobin was greater than that of B. subtilis DJ-6 in laboratory tests. Field trials revealed that al the 1∶1 000, 1∶2 000 and 1∶3 000 dilu-tions of 20% pyraclostrobin·2×1011 cfu/g B. subtilis DJ-6 WP in combination, 1∶1 000 dilution of 1 ×1012 cfu/g B. subtilis DJ-6 WP and 1∶2 000 dilution of 250 g/L pyra-clostrobin EC promoted the growth of strawberry by increasing plant height, leaf petiole, leaf blade area and stem diameter. Among them, the treatments with 1∶1 000 and 1∶2 000 of 20% pyraclostrobin · 2×1011 cfu/g B. subtilis DJ-6 WP in combina-tion had better effects than other treatments. The control effects of al the treat-ments were measured 30 and 80 d after fungicide application. The control effects of 1∶1 000 dilution of 20% pyraclostrobin and 2×1011 cfu/g B. subtilis DJ-6 in combina-tion were up to 100% and 93.11%, which were higher than those in al other treat-ments. The second highest control effects were found in the treatment with 1∶ 2 000 dilution of 20% pyraclostrobin and 2×1011 cfu/g B. subtilis DJ-6 in combination, they were 92.49% and 86.49%, higher than those in other treatments except the 1∶1 000 dilution of 20% pyraclostrobin and 2 ×1011 cfu/g B. subtilis DJ-6 in combination. The control effects of 1∶3 000 dilution of 20% pyraclostrobin and 2×1011 cfu/g B. subtilis DJ-6 in combination were 82.61% and 72.42%, higher than those in treatment with 1∶1 000 dilution of 1×1012 cfu/g B. subtilis DJ-6 WP, but lower than those in treat-ment with 1∶2 000 dilution of 25% pyraclostrobin EC. [Conclusion] Al the results re-vealed that the combination use of 20% pyraclostrobin and 2 ×1011 cfu/g B. subtilis DJ-6 WP at 1∶1 000 to 1∶2 000 dilution had better control effect against strawberry Fusarium wilt.

[目的]筛选草莓枯萎病增效生物复配杀菌剂。[方法]采用菌丝生长速率法测定枯草芽孢杆菌 DJ-6与吡唑醚菌酯及其5种配比对草莓枯萎病菌的室内抑菌活性,采用田间试验测定20%吡唑醚菌酯·200亿 cfu/g枯草芽孢杆菌可湿性粉剂1000倍液、2000倍液、3000倍液以及各单剂对草莓生长性状的影响和对草莓枯萎病菌的防治效果。[结果]枯草芽孢杆菌DJ-6与吡唑醚菌酯及1∶1、1∶2、1∶3、1∶4、1∶5混配组合对草莓枯萎病菌的 EC50分别为5.3115、4.0086、3.5706、3.3509、3.2189μg/ml；5种混配组合对枯萎病菌的增效系数（SR）分别为2.28、1.77、1.53、1.64、1.11,其中以1∶1增效作用最大。20%吡唑醚菌酯·200亿cfu/g枯草芽孢杆菌可湿性粉剂三种不同浓度混配及各单剂均有促进草莓生长和防治枯萎病的效果，其中高、中浓度处理高于低浓度和单剂处理。药后30 d和80 d测定枯萎病防治效果，高浓度的防效最高为100.00%和93.11%；中浓度的防效为92.49%和86.49%，高于低浓度和各单剂处理；低浓度的防效分别为82.61%和72.42%，高于1000亿cfu/g枯草芽孢杆菌可湿性粉剂1000倍液，但低于250 g/L吡唑醚菌酯乳油2000倍液。[结论]20%吡唑醚菌酯·200亿 cfu/g枯草芽孢杆菌可湿性粉剂定植后的灌根浓度推荐为1000~2000倍液。