Late blight confirmed as US-23 in potato crop in Allegan County, MI

Willie Kirk, Sandesh Dangi, Raechel Bayma and Noah Rosenzweig, Michigan State University Extension, Department of Plant, Soil and Microbial Sciences -

The US-23 genotype is Ridomil sensitive and treatment recommendations remain the same as last week.

The genotype of the Phytophthora infestans isolate responsible for the late blight confirmation in a potato crop in Allegan County last week was the US-23 genotype. This was confirmed by GPI allozyme analysis. This genotype is Ridomil sensitive however Michigan State University Extension’s recommendations for treatment remain the same as in last week’s report and include treating with one of the translaminar fungicides listed on the Late Blight Risk Monitoring website.

Conditions remain conducive for late blight in irrigated potato crops despite the high temperatures experienced over the last few days. Forecasts and DSV accumulations can be checked daily at the Late Blight Risk Monitoring website.

Dr. Kirk’s work is funded in part my MSU’s AgBioResearch.

This article was published by Michigan State University Extension. For more information, visit https://extension.msu.edu. To have a digest of information delivered straight to your email inbox, visit https://extension.msu.edu/newsletters. To contact an expert in your area, visit https://extension.msu.edu/experts, or call 888-MSUE4MI (888-678-3464).

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