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Potato late blight is a major disease affecting potato yield and can infect potato at different growth stages. The selection of appropriate fungicides to effectively control potato late blight is of great significance to potato production safety and increase of farmer's income. To select better fungicides for the prevention and control of autumn potato late blight, the field efficacy of four fungicides commonly used in potato late blight prevention and control were compared. The fungicides were applied five times during potato growth period. The incidence of each treatment was investigated, and the incidence, disease index and control effect were calculated. All four fungicides had good control effect, and the ranking of average control effect was 687.5 g/L Fluopicolide propamocarb SC > 10% Oxathiapiprolin OD > 100 g/L Cyazofamid SC > 50% Dimethomorph WP. Among them, the total average control effect of 687.5 g/L Fluopicolide propamocarb SC was the best, which was 70.90%, followed by 10% Oxathiapiprolin OD, which was 66.53%. In potato autumn planting season, 687.5 g/L Fluopicolide propamocarb SC and 10% Oxathiapiprolin OD could be used alternately for prevention and control of potato late blight. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]