Fusarium Head Blight Status – June 24

While much of the winter wheat crop is well past flowering, there are still pockets of the state, especially near Lake Michigan with wheat heading into flowering this week. The current Fusarium head blight forecast shows a low risk for the majority of the state, however, there are some pockets in west central and southwest with a medium risk for infection, and pockets along Lake Michigan and the northwestern portion of the state in the high risk category (Figure 1). The one to three day risk maps show a reduce area under risk for Fusarium head blight each day.

Figure 1. Risk map for Fusarium head blight in Wisconsin on June 24, 2009. The 1-3 day forecast map shows a reduction in the area under a medium to high risk. Much of the wheat crop in the state is past flowering, however, we have received some reports of crops just now into the flowering growth stage.

Current FHB Status: Today (June 24), both Shawn and I were at the Winter Wheat Variety Trial site at Lancaster. Low levels of FHB were noted in the trial (See images below). Our preliminary observations indicate the highest level of incidence level (i.e., the number of infected heads) is around 9% in only a few plots and that the severity of infected kernels is very low (meaning that index values that are a measure of incidence and severity are less than 1% at the moment). We will be taking our more detailed field notes for FHB over the next week as we move into the soft dough growth stage. This is our recommended timing for FHB assessments for growers and others as well. Assessments for FHB can be made in the field by assessing 100 consecutive heads, noting the number of heads with symptoms of FHB and also the severity of infected heads (the number of kernels infected on a head).
Rainfall over the past week at the winter wheat variety trial locations (June 17 to June 24):
Arlington = 1.7 inches (temperatures ranged from the 60s into the 90s)
Chilton = 0.2 inches (temperatures ranged from the 50s to around 90)
Janesville = 2.64 inches (temperatures similar to Arlington)
Lancaster = 1.38 inches (temperatures similar to Arlington and Janesville)

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