The Efficacy Of Two Biocontrol Strains On Wheat Head Blight And Crown Rot Diseases

Wheat Fusarium head blight(FHB)is a common wheat disease,which has caused great yield loss of wheat in China.Fusarium graminearum is one main pathogen of this disease,the fungus is dapted to wide a range of temperature and host.Spraying chemical fungicides at wheat flowering stage can reduce the incidence of the disease to a certain extent.However,the environmental problems caused by the massive use of chemical fungicides,such as soil pollution and water pollution,are becoming increasingly prominent.In addition,the occurrence of F.graminearum has resistance to chemical fungicides was increased,and resulted in a vicious circle.Biological control,with its advantages of high efficiency and low pollution,has attracted the attention of researchers in the world.The present study tried to explore the antagonistic activity and control efficacy of Irpex lacteus strain DK6 and Bacillus amyloliquefaciens strain HZ-25.The results are summarized as follows:1.After checked the antagonistic activity of I.lacteus,we found that there is no antifungal zone in PDA plate.However,the strain DK6 can grow to cover the F.graminearum.In the double dish buckle teste,the liquid fermentation of strain DK6 can release volatile gas which able to inhibite the growth of F.graminearum hyphae.In addition,microscopic observation showed that the volatile gas made F.graminearum hyphal tip appeared obvious bifurcation.Culturing F.graminearum on PDA containing liquid fermentation of I.lacteus,it is showed that the hyphal growth of F.graminearum was inhibited.And the higher concentration of fermentation,the stronger of inhibit effective.2.When dual cultured strain HZ-25 and F.graminearum on PDA plate,the F.graminearum inhibition rate reached 69.92%,In addition,F.graminearum growth inhibition rate reached 69.21% on a plate containing 20% HZ-25 fermentation.The inhibition rate of volatile gas released by HZ-25 to the growth of F.graminearum was 40.04%.By morphological identification and molecular analysis,HZ-25 was identified as a Bacillus amylobacillus.3.The pot experiment to explore the control effect of I.lacteus and B.amyloliquefaciens on wheat crown rot disease was conducted.Results showed DK6 and HZ-25 can effectively prevent Fusarium root and crown rot of wheat.In the preventive test,the control effect of strain HZ-25 on Fusarium root and crown rot of wheat was 51.11%,which is slightly higher than that of strain DK6 with 46.67%.While the disease control effect of strain DK6 was 43.78%,which is lower than that of strain HZ-25 with 46.15%.In addition,the results showed that the liquid fermentation of DK6 and HZ-25 can promote the growth of wheat.4.The field test was carried to explore the control effect of strain DK6 and HZ-25 on Wheat Fusarium head blight disease.The results showed that control effect of HZ-25 suspension on disease was 42.42%,while the fermentation liquid of DK6 control effect was 37.88%,which is slightly lower than that of the HZ-25 suspension.Further more,the fementation broth of strain DK6 able to increase the thousand-grain weight of wheat to 4.36 g,which is higher than the water treatment negative control.In this study,we found two strains DK6 and HZ-25 have potential to biocontrol diease caused by F.graminearum,which give us a selective way to reduce the use of chemical fungicide and a convinent methord to biocontrol wheat disease.In addition,the study about using strain DK6 to control diease makes up for the blank of I.lacteus in the prevention and control of wheat crown rot disease,and provides a theoretical basis for further exploration.