‘滁菊'叶部病害病原菌鉴定与化学防治.

[Objectives]The paper aimed to clarify the pathogenic fungi of ‘Chuju' leaf disease and screen the effective chemical pesticides for effective control of the occurrence of diseases in ‘Chuju'. [Methods]The pathogenic fungi were isolated and purified by tissue isolated method, and morphological identification, molecular biological identification and pathogenicity determination, and the primary pathogenic fungi that caused ‘Chuju' leaf diseases were identified. The plate toxicity test was utilized to detect the antifungal effect of 13 fungicides and to screen for the effective drug and control concentration. The foliar mycelial adherence method was used to inoculate with pathogenic fungi in potted chrysanthemum seedlings, and the control effect of screening agents was further determined on live potted seedlings. [Results]The main pathogens fungi isolated from the diseased leaves of ‘Chuju' were Alternaria alternata, Alternaria longipes and Alternaria tenuissima. The results of the plate toxicity test showed that difenoconazole·azoxystrobin had the best effect on mycelial growth inhibition of Alternaria(CJ31, CJ4-1), and hexaconazole had the best effect on mycelial growth inhibition of Alternaria(CJ3-1, CJ37), iprodione had the best inhibitory effect on mycelial growth of Alternaria(CJ30), and all EC50 values were below 7 mg·L-1. According to the efficacy test of the potted medicines, the control effect on Alternaria proved better with iprodione 500 times dilution solution and hexaconazole 3 000 times dilution solution. [Conclusions]In the main production areas of ‘Chuju', the main pathogen causing leaf diseases was Alternaria, which caused black spot disease of ‘Chuju'. Iprodione, hexaconazole and difenoconazole·azoxystrobin were recommended as the pesticides of choice for controlling leaf diseases in the field of ‘Chuju'. [ABSTRACT FROM AUTHOR]