Phytoparasitica (2008) 36, 326-337

Yu Chen, Hengkui Li, Changjun Chen and Mingguo Zhou (2008)
Sensitivity of Fusarium graminearum to fungicide JS399-19: In vitro determination of baseline sensitivity and the risk of developing fungicide resistance
Phytoparasitica 36 (4), 326-337
Abstract: The baseline sensitivity of Fusarium graminearum Schwade [teleomorph = Gibberella zeae (Schweinitz) Petch] to the fungicide JS399-19 (development code no.) [2-cyano-3-amino-3-phenylacrylic acetate] and the assessment of risk to JS399-19 resistance in vitro are presented. The mean EC50 values for JS399-19 inhibiting mycelial growth of three populations of wild-type F. graminearum isolates were 0.102±0.048, 0.113±0.035 and 0.110±0.036 µg ml^-1, respectively. Through UV irradiation and selection for resistance to the fungicide, we obtained a total of 76 resistant mutants derived from five wild-type isolates of F. graminearum with an average frequency of 1.71×10−7% and 3.5%, respectively. These mutants could be divided into three categories of resistant phenotypes with low (LR), moderate (MR) and high (HR) level of resistance, determined by the EC50 values of 1.5-15.0 µg ml^-1, 15.1- 75.0 µg ml^-1 and more than 75.0 µg ml^-1, respectively. There was no positive crossresistance between JS399-19 and fungicides belonging to other chemical classes, such as benzimidazoles, ergosterol biosynthesis inhibitors and strobilurins, suggesting that JS399-19 presumably has a new biochemical mode of action. Although the resistant mutants appeared to have comparable pathogenicity to their wild-type parental isolates, they showed decreased mycelial growth on potato-sucrose-agar plates and decreased sporulation capacity in mung bean broth. Nevertheless, most of the resistant mutants possessed fitness levels comparable to their parents and had MR or HR levels of resistance. As these studies yielded a high frequency of laboratory resistance in F. graminearum, appropriate precautions against resistance development in natural populations should be taken into account.
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Link to article at publishers website
Database assignments for author(s): Ming-Guo Zhou, Chang-Jun Chen

Research topic(s) for pests/diseases/weeds:
control - general
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Fusarium graminearum