| JS399-19 (2-cyano-3-amino-3-phenylacrylic acetate) is a high efficient fungicide withnew structure and unique function. The effect of JS399-19 on mecylial growth in vitro washigh against F. moniliforme. The EC50 inhibiting mycelia growth was 0.2603±0.0541μg/ml.But the effect of JS399-19 on conidial germination was low. The EC50 were 30.9286μg/ml.JS399-19 could not kill the mycelia ofF. moniliforme. After mycelia of E moniliformeimmersed for 72h in liquid media containing 10μg/ml JS399-19, mycelia could recovergrowth on the fungicide-free plates. MIC of JS399-19 inhibited mycelial growth of 52strains of E moniliforme was 20μg/ml. EC50 value inhibiting mycelial growth was0.2603±0.0541μg/ml.Resistant mutants have not been obtained from 5 wild-type sensitive strains of F.moniliforme by UV irradiation on the conidia. Eight mutants resistant to JS399-19 wereobtained from three wild-tyoe sensitive srains by fungicide treatment. EC50 of the 8resistant strains were higher than their parental stains. Resistance enhancement were 1 to5. Resistance enhancement of only one mutant Gtd -2 was 5.5139, reaching the resistantstandard of FAO. According to EC95, resistance enhancement of the 8 resistant strains were4 to 27, but resistance enhancement of Gtd -2 was lower than 5 (4.0281). The other werehigher than 5, reaching the resistant standard. The resistance risk of JS399-19 was upwardsmiddle level. Risk of resistance F. moniliforme to JS399-19 need to be monitored regularly.The biological properties of mutant strains of F. moniliforme induced by the JS399-19indicated that the resistance of mutant strains to the JS399-19 could be stably inherited for20 transfers. Further study is needed to elucidate that whether the resistance can beinherited by sexual reproduction. By the test in vitro, it was noticeable that the growth rateof mutant strains had little difference from that of wild strains, while the microsporesproductivity of mutant strains was extremely significantly lower than that of parental wildstrains. This was not suitable for the JS399-19 resistance to form. Pathogenicity test inieatcd that there was little difference in microspores virulence between the mutant strainsand their parental wild strains.It was indicated that the antifungal activity of JS399-19 against four strains was lowerthan that of prochloraz on mycelial growth of F. moniliforme in vitro. But there was nosignificant difference in control efficacy on F. moniliforme of these two fungicides byputting seeds in fungicides at the same concentration. This research suggested thatJS399-19 could be applied to controling F. moniliforme by replacing prochloraz, and therewas no cross resistance between JS399-19 and prochloraz. Results of this study showedthat the control efficacy was higher than 90％when putting seeds in 1:3000-1:4000 timessolution of 25％JS399-19 SC for 48h. So it was suitable for generalization and applicationof this new fungicide.JS399-19 did not affect the germination and growth of dee seed. After immersed for144h in lower temperature(10℃), and then 48h in higher temperature(25℃), the seedscould still germinate.
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