Lukasko Nicole T, Hausbeck Mary K
Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI 48824.
Plant Dis. 2024 Feb;108(2):278-285. doi: 10.1094/PDIS-06-23-1213-SR. Epub 2024 Feb 18.
The fungal pathogen is a notorious problem on many floriculture greenhouse hosts including petunia, geranium, and poinsettia; these key crops contribute to the $6.43 billion U.S. ornamental industry. While growers use cultural strategies to reduce relative humidity and free moisture to limit Botrytis blight, fungicides remain a primary component of control programs. Isolates ( = 386) of sampled from symptomatic petunia, geranium, and poinsettia in Michigan greenhouses from 2018 to 2021 were screened for resistance to eight fungicides belonging to seven Fungicide Resistance Action Committee (FRAC) groups. Single-spored isolates were subjected to a germination-based assay using previously defined discriminatory doses of each fungicide. Resistance was detected to thiophanate-methyl (FRAC 1; 94%), pyraclostrobin (FRAC 11; 80%), boscalid (FRAC 7; 67%), iprodione (FRAC 2; 65%), fenhexamid (FRAC 17; 38%), cyprodinil (FRAC 9; 38%), fludioxonil (FRAC 12; 21%), and fluopyram (FRAC 7; 13%). Most isolates (63.5%) were resistant to at least four FRAC groups, with 8.7% of all isolates demonstrating resistance to all seven FRAC groups tested. Resistance frequencies for each fungicide were similar among crops, production regions, and growing cycles but varied significantly for each greenhouse. Phenotypic diversity was high, as indicated by the 48 different fungicide resistance profiles observed. High frequencies of resistance to multiple fungicides in populations from floriculture hosts highlight the importance of sustainable and alternative disease management practices for greenhouse growers.
这种真菌病原体在许多花卉温室寄主上都是一个臭名昭著的问题，包括矮牵牛、天竺葵和一品红；这些关键作物对价值64.3亿美元的美国观赏植物产业有重要贡献。虽然种植者采用栽培策略来降低相对湿度和游离水分以限制灰霉病，但杀菌剂仍然是防治方案的主要组成部分。2018年至2021年期间，从密歇根州温室中有症状的矮牵牛、天竺葵和一品红上采集了386个菌株样本，对其进行了针对属于七个杀菌剂抗性行动委员会（FRAC）组的八种杀菌剂的抗性筛选。单孢分离株使用每种杀菌剂预先确定的鉴别剂量进行基于萌发的测定。检测到对甲基硫菌灵（FRAC 1；94%）、吡唑醚菌酯（FRAC 11；80%）、啶酰菌胺（FRAC 7；67%）、异菌脲（FRAC 2；65%）、氟酰胺（FRAC 17；38%）、嘧菌环胺（FRAC 9；38%）、咯菌腈（FRAC 12；21%）和氟吡菌酰胺（FRAC 7；13%）有抗性。大多数分离株（63.5%）对至少四个FRAC组有抗性，所有分离株中有8.7%对测试的所有七个FRAC组都有抗性。每种杀菌剂的抗性频率在作物、生产地区和生长周期之间相似，但每个温室的抗性频率差异显著。如观察到的48种不同的杀菌剂抗性谱所示，表型多样性很高。花卉寄主群体中对多种杀菌剂的高抗性频率凸显了温室种植者采用可持续和替代病害管理措施的重要性。
