Preliminary Studies On The Synergistic Control Of Fusarium Wilt Of Bitter Gourd By Combination Strains And Methyl Jasmonate

Fusarium wilt of bitter gourd is an important soil-borne disease caused by Fusarium oxysporum f.sp.momordicae,which has now seriously influenced the development of bitter gourd industry.Fusarium wilt of bitter gourd was served as target disease in this study.Five biocontrol agents such as Chaetomium globosum strain ND35,Bacillus amyloliquefaciens strain SK2,Penicillium purpurogenum strain Q2,Trichoderma asperellum strain MX,Trichoderma virens strain M2 with different mechanisms of action and the inducer Methyl jasmonate?MeJA?have been variously combined.And control effects of various combinations on Fusarium wilt of bitter gourd have been investigated in greenhouse and in the field.The results show as follows:1.Single plate confrontation test results showed that the strain ND35,strain SK2,strain Q2,strain MX,strain M2 suppressed mycelia growth of F.oxysporium f.sp.momordicae strain SG-15 on the flat plate,Strain MX with inhibitory rate of 87.92%was the best.However,there was obvious inhibitory zone between biocontrol strain SK2 and pathogenic strain SG-15.Inhibition percentage of strain SK2 against pathogenic strain SG-15 was71.75%.2.The results of biocontrol agents compatibility test showed that there was an inhibitory zone between strain SK2,strain ND35 and strain M2.But there was not inhibitory zone between other strains.3.The results of potting test showed that biocontrol agents combination series 1 were not able to control Fusarium wilt of bitter gourd,and the incidence and disease index was increased.But the incidence and disease index could be decreased after combination treatment with 0.001 mM of MeJA solution.The incidence of bitter gourd wilt was 57.14%and 42.86%in treatment group TA+MeJA and TB+MeJA,respectively.and the control effect was 49.20%and 52.38%,respectively.Biocontrol agents combination series 2 in pot experiment were able to control Fusarium wilt of bitter gourd in each treatment group,and the control effect of treatment group A,B and C was 29.03%,27.1%,36.17%,respectively.The results of effect of biocontrol agents combination series 2 on the defence enzymes in the leaves of Momordica charantia L showed that activity of peroxidase?POD?reached the peak of the whole test period in the treatment group A,and the enzyme activity value was 393.22 U·g^-1·min^-1.The activity values of phenylalanine ammonia-lyase?PAL?and polyphenol oxidase?PPO?reached the peak of the whole test period in the treatment group C,and the enzyme activity values were 129.28 U·g^-1·min^-1,173.47 U·g^-1·min^-1,respectively.The peak value of peroxidase?POD?activity in treatment group C was slightly lower than that of treatment group A,and its enzyme activity value was 384.89 U·g^-1·min^-1.4.The results of the field test showed that the cooperation of biocontrol agents combination A and MeJA was able to control synergisticly Fusarium wilt of bitter gourd.The control effect of treatment with biocontrol agents combination A was 39.71%,however,the control effect of the cooperation of biocontrol agents combination A and MeJA on bitter gourd wilt reached 86.09%,but there was not control effect on bitter gourd wilt in the treatment with MeJA alone.The effect of fruits yield increase was significant in treatment group A+MeJA.