Location: Sugarbeet and Bean ResearchTitle: Alternaria leaf spot of sugar beet: factors associated with risk Author
|Jiang, Qianwei - Michigan State University|
|Wu, Hanghang - Michigan State University|
|Mcgrath, J Mitchell - Mitch|
Submitted to: Journal of Sugar Beet Research
Publication Type: Abstract Only
Publication Acceptance Date: 2/27/2017
Publication Date: 2/27/2017
Citation: Hanson, L.E., Jiang, Q., Wu, H., McGrath, J.M. 2017. Alternaria leaf spot of sugar beet: factors associated with risk. Journal of Sugar Beet Research. 54(1&2):16.
Technical Abstract: Recently, increased incidence and severity of Alternaria leaf spot has been observed in Michigan and other growing regions. In the past, Alternaria leaf spot in sugar beet has been a minor foliar disease issue in the United States and management of this disease usually has not been required. If severe, there is a potential to cause yield loss due to defoliation. The aim of this work was to examine disease management implications. Testing included screening Alternaria leaf spot susceptibility in sugar beet germplasm as well as testing the response of Alternaria spp. (all in the A. alternate species complex) from beet to foliar fungicides. Over 70% of the recent isolates (last two years) were resistant to quinone outside inhibitor (QoI) fungicides, with EC50 values greater than 60 ppm. Over 90% of the isolates showed tolerance to organotin, with EC50 values between 5 and 10 ppm. Sugar beet germplasm with differential reaction to Alternaria are being screened in the greenhouse, which includes a detached leaf assay and a mist chamber assay.