Alyssa K. Betts, Extension Field Crops Pathologist; akoehler@udel.edu
Wheat is actively flowering and brought some intermittent rain with it. We are currently at medium to high risk for FHB in susceptible varieties (Figure 1). Fungicide applications are in progress across much of the state. Additional details on fungicide application can be found in the April 5 WCU and other recent articles. This year it appears we have an added disease in the region. I confirmed stripe rust in my plots with a susceptible wheat variety earlier this week (Figure 2). So far, I have seen low incidence just a few leaves mostly at the edge of the field with 1-2 stripes per plant. Varieties that are resistant and moderately resistant to stripe rust are at low risk, those rated as susceptible or moderately susceptible should be monitored. FHB products like Miravis Ace, Prosaro, Prosaro Pro, Sphaerex will also have activity on stripe rust. If using fungicides for stripe rust after this window, keep an eye on pre-harvest restrictions. The Fungicide Efficacy for Control Of Wheat Diseases Table hosted on the Crop Protection Network is a great resource to compare efficacy ratings and review harvest restrictions. Folicur (tebuconazole) has a rating of excellent for stripe rust and a 30-day-pre-harvest restriction.
Figure 1. FHB Risk Model for very susceptible wheat on May 9, 2024 (wheatscab.psu.edu)
Figure 2. Wheat leaf with stripe rust