JS399-19, a new fungicide against wheat scab

JS399-19, 2-cyano-3-amino-3-phenylancryic acetate, belongs to the cyanoacrylate fungicide group. The antifungal properties of this compound were tested against 12 economically important plant pathogens. Although JS399-19 strongly inhibited the mycelial growth of Fusarium graminearum, Fusarium moniliforme and Fusarium oxysporum with EC50 values of 0.126±0.027 μg ml−1 (mean±standard deviation, SD), 0.459 and 3.565 μg ml−1, respectively, it demonstrated little or no bioactivity against mycelial growth of other tested fungal pathogens. JS399-19 did not express cross-resistance with other well-known fungicides belonging to different chemical groups, such as benzimidazoles, ergosterol biosynthesis inhibitors, strobilurins, dithiodicarbamates and aromatic hydrocarbons, which implied that JS399-19 probably acted through a different biochemical mechanism. Results from field experiments showed that the efficacy of JS399-19 in controlling wheat scab at a treatment concentration of 562.5 g ai ha−1 was better than that of carbendazim treatment at 750 g ai ha−1. Meanwhile, in pots treated with JS399-19, the frequency of carbendazim-resistant isolates in the pathogen population was only 1.39%, while in pots treated with carbendazim, resistance frequency increased to 13.37%, and resistant isolates formed 2.91% of the population in pots that were not chemically treated. The effectiveness of JS399-19 makes it suited for controlling FHB in the field, especially in areas of China where a MBC-resistant fungal population has developed.