Journal article
Resistance in Strawberry Isolates of Colletotrichum acutatum from Florida to Quinone-Outside Inhibitor Fungicides
Plant disease, Vol.100(10), pp.2050-2056
10/2016
Handle:
https://hdl.handle.net/2376/114722
PMID: 30683005
Abstract
Anthracnose fruit rot of strawberry, caused by Colletotrichum acutatum, is a major disease in Florida and frequent quinone-outside inhibitor (QoI) fungicide applications are needed for disease control. From 1994 to 2014, 181 C. acutatum isolates were collected from multiple strawberry fields in Florida with or without QoI spray history. Sensitivity to azoxystrobin and pyraclostrobin was tested based upon mycelial growth and germ tube elongation inhibition. Mean effective concentration where growth was reduced by 50% (EC50) values for isolates collected prior to 2013 based upon mycelial growth were 0.22 and 0.013 μg/ml and upon germ tube elongation were 0.57 and 0.03 μg/ml for azoxystrobin and pyraclostrobin, respectively. Mycelial growth and germ tube elongation of 48 isolates collected in 2013 and 2014 were not inhibited with azoxystrobin at 3 μg/ml and pyraclostrobin at 0.110 μg/ml. A fungicide discriminatory dose assay indicated that 43 of the 48 isolates had EC50 values higher than 100 and 10 μg/ml for azoxystrobin and pyraclostrobin, respectively. Azoxystrobin and pyraclostrobin sprayed preventively on strawberry fruit inoculated with C. acutatum failed to control resistant isolates. Sequencing of the cytochrome b gene of sensitive and resistant isolates showed that QoI-resistant isolates contained either G143A or F129L amino acid substitutions.
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Details
- Title
- Resistance in Strawberry Isolates of Colletotrichum acutatum from Florida to Quinone-Outside Inhibitor Fungicides
- Creators
- Bruna B Forcelini - Gulf Coast Research and Education Center, University of Florida, Wimauma 33598Teresa E Seijo - Gulf Coast Research and Education Center, University of Florida, Wimauma 33598Achour Amiri - Tree Fruit Research and Extension Center, Washington State University, Wenatchee 98801Natalia A Peres - Gulf Coast Research and Education Center, University of Florida
- Publication Details
- Plant disease, Vol.100(10), pp.2050-2056
- Academic Unit
- Plant Pathology, Department of
- Identifiers
- 99900547962401842
- Language
- English
- Resource Type
- Journal article