Research article - Peer-reviewed, 2019
Within-season changes in Alternaria solani populations in potato in response to fungicide application strategies
Odilbekov, Firuz; Edin, Eva; Mostafanezhad, Hadis; Coolman, Hilde; Grenville-Briggs, Laura J.; Liljeroth, ErlandAbstract
Early blight, caused by the fungus Alternaria solani, is a common foliar disease in potato. Quinone outside inhibitor (QoIs) fungicides have commonly been used against A. solani. To avoid or delay development of fungicide resistance it is recommended to alternate or combine fungicides with different modes of action. Therefore, we compared two different fungicide programs against early blight in field trials and studied within season changes in the pathogen population. An untreated control was compared with treatments using azoxystrobin alone and with a program involving difenoconazole followed by boscalid and pyraclostrobin combined. Isolates of A. solani were collected during the growing season and changes in the population structure was investigated. We also screened for the amino acid substitution in the cytochrome b gene and investigated changes in sensitivity to azoxystrobin. Treatment with azoxystrobin alone did not improve disease control in 2014 when the disease pressure was high. However, lower severity of the disease was observed after combined use of difenoconazole, boscalid and pyraclostrobin. The efficacy of both fungicide treatments were similar during the field trial in 2017. Two mitochondrial genotypes (GI and GII) were found among isolates, where all isolates, except two, were GII. All GII isolates had the F129 L substitution while the two GI isolates were wild type. Population structure analysis and principal component analysis (PCA) of amplified fragment length polymorphisms (AFLP) data revealed within season changes in the A. solani populations in response to fungicide application. Isolates with the F129 L substitution had reduced sensitivity to azoxystrobin in vitro and their sensitivity tended to decrease with time.Keywords
Early blight; Chemical control; F129 L substitution; Fungicide resistance; Potato diseasePublished in
European Journal of Plant Pathology2019, volume: 155, number: 3, pages: 953-965
Publisher: SPRINGER
Authors' information
Mostafanezhad, Hadis
University of Tehran
Swedish University of Agricultural Sciences, Department of Plant Breeding
Swedish University of Agricultural Sciences, Department of Forest Mycology and Plant Pathology
Mostafanezhad, Hadis
University of Tehran
Mostafanezhad, Hadis
Swedish University of Agricultural Sciences, Department of Plant Protection Biology
Coolman, Hilde
No organisation
Associated SLU-program
SLU Network Plant Protection
UKÄ Subject classification
Agricultural Science
Publication Identifiers
DOI: https://doi.org/10.1007/s10658-019-01826-8
URI (permanent link to this page)
https://res.slu.se/id/publ/102504