Identification of the pathogen causing pre-harvest dark brown spots on avocado and its fungicides control in field
To investigate the pathogen causing black-brown spots on pre-harvest avocado in the germplasm resource nursery in South Subtropical Crop Research Institute,CATAS in Zhanjiang City,Guangdong Province,pathogens were isolated from infected fruits using tissue isolation,and identified by morphological and molecular biology methods.The pathogenicity of the pathogen to the fruit,leaf and stem of avocado was tested.The field control effect of 40％carbendazim suspension and 25％azoxystrobin suspension on this disease was experimented.The results showed that 36 strains isolated from 15 samples were divided into two different species of Colletotrichum,based on morphological observation and molecular identification.Phylogenetic analysis of multigene(ITS,GAPDH,CAL,TUB,and ACT)showed that representative strain YLQ5-2 and FNYG1 was clustered with Colletotrichum siamense and C.fruticola,respectively.Pathogenicity tests indicated that punctured wounds could cause black spots on avocado fruit,and leaves of avocado could be infected without wounds,but stems of avocado could not be infected with punctured wounds,showing tissue specificity of the disease.The field control effects of continuous spraying with 1,500-fold solution of 25％azoxystrobin SC and 500-fold solution of 40％carbendazim SC for three times was above 50％,with better control effect of 87.1％by 1,500-fold solution of 25％azoxystrobin SC.
万方数据
维普
