Isolation And Identification Of Pathogens Of Strawberry Root Rot And Screening Of Antagonistic Strains

Strawberry root rot is a general term for strawberry root diseases caused by various pathogenic fungi which is serious and difficult to control.At present,biological control is the most in line with the agricultural green sustainable development strategy.It is an important method for plant disease prevention and control,and it is also the development direction in the future.In this experiment,the pathogen of strawberry root rot were isolated and identified.The antagonistic strains and IAA-producing strains were screened from the bacteria which were isolated from strawberry rhizosphere soil.Finally,preliminary disease control experiments were performed on strawberry plants by using the antagonistic strains with better effects.The main results are summarized as follows:1.In this experiment,strawberry root rot disease samples were collected from Changping District and Daxing District of Beijing and Modern Agriculture Park of Hohhot during the strawberry growth period.35 fungi were isolated from the diseased plant sample.Two strains were confirmed as strawberry root rot pathogen by Koch's Rule,and identified as Colletotrichum siamense and Fusarium oxysporum respectively by morphological and molecular biological methods.And this is also the first report that Colletotrichum siamense causing root rot on strawberry.2.400 strains of bacteria were isolated from strawberry rhizosphere soil,and it contained 16 strains that could antagonize Fusarium oxysporum,20 strains that could antagonize Colletotrichum siamense,and 240 strains that could produce IAA.And there were 24 strains with IAA production greater than 34.34 mg/L.3.15 strains which have good antagonistic effects and IAA production ability were identified by 16S rRNA sequence analysis.Seven of them belong to Bacillus sp.,six strains belong to Pantoea sp.,and the other two strains belong to Paenibacillus sp.and Pseudomonas sp.respectively.4.Two strains with good antagonistic effect on Colletotrichum siamense and Fusarium oxysporum which with the capable of secreting IAA were selected effectively for the preliminary pot experiment,and the results showed that the 4 functional bacteria were failed to control strawberry root rot effectively.