Marin Marcus V, Seijo Teresa E, Zuchelli Elias, Peres Natalia A
Gulf Coast Research and Education Center, University of Florida, Wimauma, FL 33598, U.S.A.
Institute of Agriculture, University of Tennessee, Jackson, TN 38301, U.S.A.
Plant Dis. 2021 Nov;105(11):3490-3495. doi: 10.1094/PDIS-11-20-2474-RE. Epub 2021 Nov 18.
and cause leather rot on fruit and crown rot (PhCR) of strawberry plants. Leather rot is not a common disease in Florida; however, up to 50% yield loss has been reported in harvests after intense rainfall events. PhCR is an important disease worldwide and is characterized by a sudden wilting and collapse of plants. Mefenoxam is the most effective and widely used fungicide to control both diseases. and isolates from leather rot and PhCR have been collected from multiple strawberry fields in Florida since 1997, and the sensitivity of 185 isolates was tested at 0, 0.05, 0.5, 5, and 100 µg/ml. The 50% effective concentration (EC) values of sensitive isolates ranged from 0.05 to 1 µg/ml. Resistance to mefenoxam (EC values >100 µg/ml) was found among isolates collected after 2015, but no resistance was found in isolates. During the 2015 to 2016, 2016 to 2017, 2017 to 2018, and 2018 to 2019 seasons, resistance was detected on 9, 10, 21, and 23% of the isolates collected, respectively. Mefenoxam-resistant isolates originated from 3 of the 24 strawberry nurseries monitored. This is the first report of the occurrence of resistance to mefenoxam in Florida, suggesting that alternative control strategies are needed to avoid the increase of mefenoxam-resistant populations of in Florida fields.
并导致果实出现皮革腐烂以及草莓植株发生冠腐病（PhCR）。皮革腐烂病在佛罗里达州并不常见；然而，据报道，在暴雨事件后的收获季，产量损失高达50%。PhCR是一种在全球范围内都很重要的病害，其特征是植株突然萎蔫和倒伏。甲霜灵是防治这两种病害最有效且使用最广泛的杀菌剂。自1997年以来，已从佛罗里达州的多个草莓田收集了皮革腐烂病和PhCR的 分离株，并在0、0.05、0.5、5和100 µg/ml的浓度下测试了185个分离株的敏感性。敏感分离株的50%有效浓度（EC）值在0.05至1 µg/ml之间。在2015年后收集的 分离株中发现了对甲霜灵的抗性（EC值>100 µg/ml），但在 分离株中未发现抗性。在2015至2016年、2016至2017年、2017至2018年和2018至2019年生长季，分别在9%、10%、21%和23%的收集分离株中检测到抗性。抗甲霜灵的分离株源自监测的24个草莓苗圃中的3个。这是佛罗里达州首次报道 对甲霜灵产生抗性，表明需要采取替代防治策略以避免佛罗里达州田间抗甲霜灵的 种群增加。
