FHB Update from MO, 05/08/19

Prolonged wet weather has lingered over much of the state in the past few weeks as the southern half of the state approached flowering and is predicted into the coming week as the northern half of the approaches flowering. At this time, conditions in much of the state place the more susceptible winter wheat varieties at high risk for FHB development. Moderate risk levels are predicted for the moderately susceptible and moderately resistant varieties are at moderate risk. Into the coming week, humidity is expected to remain high across much of the state meaning the risk for FHB development remains high likely into the coming week. Now is the critical time to make decisions regarding fungicide applications. There are several fungicides labeled for the control and management of FHB in the triazole class (including Prosaro and Caramba) which are most effective when applied at Feekes 10.5.1 (50% of the plants in the field are beginning to flower). While fungicides provide the most effective control when applied at Feekes 10.5.1, university research has shown that a fungicide applied up to 5 days after Feekes 10.5.1 may provide similar control. It is important to note that strobilurin-containing fungicides are not labelled for control of Fusarium head blight and, if applied at later growth stages such as Feekes 10.5.1, may result in increased DON levels in the grain. Always follow harvest restrictions and label instructions when applying fungicides.

--Kaitlyn Bissonnette, Extension Plant Pathologist, University of Missouri

For more details, go to the FHB Risk assessment tool at http://www.wheatscab.psu.edu

For the latest news and updates from the U.S. Wheat & Barley Scab Initiative, go to https://www.scabusa.org