哈茨木霉VT9-3r和枯草芽孢杆菌VT4-1x对3株马铃薯致病菌的抑制作用效果

Inhibition effects of Trichoderma harzianum VT9-3r and Bacillus subtilis VT4-1x on three potato pathogens

为探明生防菌哈茨木霉(Trichoderma harzianum)VT9-3r和枯草芽孢杆菌(Bacillus subtilis)VT4-1x对马铃薯致病菌Rhizoctonia solani、Fusarium oxysporum、Alternaria solani的抑制作用,采用对峙培养确定生防菌株抑菌作用,利用扫描电镜观察生防菌株对病原菌菌丝生长的影响,并采用盆栽试验分析其对由R.solani引起的马铃薯黑痣病的防效。结果表明:T.harzianum VT9-3r和B.subtilis VT4-1x能有效抑制3株病原菌的生长;B.subtilis的菌体和代谢物质都具有抑制作用,拮抗抑菌率由大到小依次为A.solani(55.4%)>R.solani(51.3%)>F.oxysporum(48.1%),无菌代谢液对病原菌的抑制率随着浓度升高而增强;扫描电镜观察发现T.harzianum通过竞争和重寄生作用抑制病原菌,拮抗抑菌率F.oxysporum(64.0%)>R.solani(63.6%)>A.solani(60.2%),其无菌代谢液抑菌效果则较差;盆栽试验表明2种生防菌剂处理后,均能显著防治R.solani引起的马铃薯黑痣病,且使用两菌剂以1∶1体积比复合处理后,防效高达81.5%。综上,哈茨木霉主要通过重寄生、枯草芽孢杆菌通过拮抗机制抑制马铃薯致病菌,2种不同抑菌机制的菌剂复配施用能更有效防治马铃薯黑痣病。

To study the inhibition effects of Trichoderma harzianum VT9-3 rand Bacillus subtilis VT4-1 xon potato pathogens(Rhizoctonia solani,Fusarium oxysporum and Alternaria solani),the dual culture test was adopted to determine the antagonistic ability of the biocontrol strains,and the influence of the biocontrol strains on the mycelial growth of the pathogens was observed by scanning electron microscope.Pot experiment was conducted to investigate the ability of the bio-control agents for preventing black scurf of potato caused by R.solani.The results showed that these two bio-control strains could inhibit the growth of three pathogens:The inhibitory effect of B.subtilis on the pathogens in descending order was A.solani(60.3%)>R.solani(56.4%)>F.oxysporum(53.2%),and its metabolites displayed obvious inhibitory effect on pathogens;T.harzianuminhibited pathogens through competition and heavy parasitism,with the bacteriostatic rates in descending order was F.oxysporum(76.9%)>R.solani(66.9%)>A.solani(59.6%);The pot experiment presented that these two biocontrol strains could significantly prevent the potato black scurf,and the control effect of combing these two(1∶1)was further improved,and reached 81.5%.In conclusion,T.harzianum’s inhibition effect mainly relies on parasitism,while B.subtilis is through hantagonistic mechanism.The combination of two different bacteriostatic mechanisms could control the common soilborne fungal diseases and promote the growth of potato seedlings.