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Diversity and Virulence of Alternaria spp. Causing Potato Early Blight and Brown Spot in Wisconsin.

A new interesting article has been published in Phytopathology. 2018 Sep 26. doi: 10.1094/PHYTO-06-18-0181-R. and titled:

Diversity and Virulence of Alternaria spp. Causing Potato Early Blight and Brown Spot in Wisconsin.

Authors of this article are:
Ding S Meinholz K Cleveland K Jordan SA Gevens AJ.

A summary of the article is shown below:
Early blight, caused by Alternaria solani, along with brown spot caused by A. alternata, have the potential to reduce quality and yield in potato production globally. Prior to this study, the incidence, disease impact, and fungicide resistance attributes of A. alternata in Wisconsin were poorly understood. Potato pathogens were isolated from foliar lesions at three commercial locations in Wisconsin in 2012 and 2017 and were initially morphologically identified as A. solani (n=33) and A. alternata (n=40). Identification were further corroborated with the phylogenetic analysis of ITS, TEF1, gapdh, Alt a 1, and OPA10-2. A multi-gene phylogeny of ITS, TEF1, gapdh, and Alt a 1 showed five genotypes of A. alternata and one single genotype of A. solani. We demonstrated that the A. alternata isolates were virulent on potato cultivars Russet Burbank (P < 0.013) and Atlantic (P < 0.0073), though they caused less disease than A. solani (P < 0.0001, P < 0.0001). Alternaria alternata caused little disease on the breeding line 24-24-12 (P = 0.9929), and A. solani caused less disease on 24-24-12 than on Russet Burbank (P < 0.0001) or Atlantic (P < 0.0001). Breeding line 24-24-12 may be a promising source of potential resistance for the two diseases. There was no significant difference in virulence of different A. alternata genotypes, and no significant difference in virulence or genotype clustering among isolates from the three locations. Isolates of A. alternata that induced chlorosis caused larger lesion areas than isolates that did not in Russet Burbank (P < 0.0001), Atlantic (P < 0.0001), and 24-24-12 (P = 0.0365). There was no significant difference in virulence between QoI-sensitive and QoI-resistant isolates of A. alternata. This study enhanced our understanding of potato early blight and brown spot in Wisconsin, and suggested that A. alternata in addition to A. solani should be carefully monitored and possibly uniquely managed in order to achieve overall disease control.
Check out the article’s website on Pubmed for more information:



This article is a good source of information and a good way to become familiar with topics such as: Disease control and pest management;Ecology and epidemiology;Mycology.

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