Preliminary identification of the pathogen causing Polygonatum kingianum anthracnose and their sensitivities to three fungicides

A total of 40 Colletotrichum strains causing anthracnose on Polygonatum kingianum were isolated and identified by morphology and ITS sequence in 2019. They were collected from three producing regions in Yunnan Province. Their sensitivities to fluazinam, prochloraz and difenoconazole were tested using the mycelium growth rate method. The results showed that all the 40 strains isolated from P. kingianum diseased leaves might belong to genus of Colletotrichum, i.c. C. gloeosporioides, C. fructicola, C. boninense and C. acutatum. Among them, 29 strains belong to C. fructicola, accounting for 72.5% of the total isolated strains. Fungicide sensitivity tests indicated that fluazinam, prochloraz and difenoconazole showed strong antifungal activities against the growth of all the tested strains. The EC₅₀ values of fluazinam, prochloraz and difenoconazole to all tested strains were in the range of 0.028-0.53 mg/L, 0.018-2.69 mg/L and 0.158-2.57 mg/L, respectively. The sensitivities of all strains to fluazinam were higher than those to prochloraz and difenoconazole. No resistant strains to fluazinam, prochloraz and difenoconazole were found in those three producing regions of Yunnan Province.