There is a high risk of fusarium head blight in wheat in Missouri this year. Farmers should monitor weather conditions carefully when wheat begins to flower and prepare to apply fungicides, University of Missouri plant pathologist Kaitlyn Bissonnette says.

Missouri wheat growers should scout fields and prepare to spray now to prevent FHB, which is also called scab, Bissonnette says. Wheat development currently is lagging seven to 10 days because of delays caused by a late 2018 harvest, a lingering winter and cool spring weather.

Bissonnette says it is too late for many southeast Missouri wheat growers as wheat passed the stage where spraying is recommended. However, farmers in southwestern, central and northern Missouri still have time to protect flowering plants.

Need to treat

FHB reduces grain yield and quality. Infected kernels shrivel, weigh less and can be contaminated with deoxynivalenol (DON), also called vomitoxin. Symptoms of infection generally begin 14 to 21 days after flowering and include bleaching of individual or whole parts of the wheat head.

An integrated approach to management includes selection of FHB-resistant wheat varieties and timely application of a fungicide to prevent disease when relative humidity is high and temperatures range from 75 to 85 degrees F, conditions that favor FHB development.

WHITE OUT: Symptoms of fusarium head blight begin as bleaching of single or multiple florets or spikelets (A), or bleaching of whole portions of the head (B).

No variety offers complete resistance to scab and the mycotoxins it produces, Bissonnette says, but some varieties are more resistant than others.

What to spray

Bissonnette says several labeled fungicides in the triazole class (FRAC 3) and a newly labeled multiple-mode-of-action product containing a triazole and an SDHI (succinate-dehydrogenase inhibitor, FRAC 7) provide effective control when applied at Feekes growth stage 10.5.1 (50% of heads are flowering). University research shows that a triazole fungicide applied up to five days after Feekes 10.5.1 may provide similar control.

Bissonnette says that strobilurin-containing fungicides are not labeled for control of FHB. If applied at later growth stages such as heading or early flowering, application could result in increased DON levels in grain.

The Fusarium Head Blight Prediction Center, a website hosted by Penn State University and supported in part by the U.S. Wheat and Barley Scab Initiative, offers state- and region-specific information about current and predicted risk of FHB.

MU Extension contributes to this site. Visit wheatscab.psu.edu for daily risk map updates.

Source: The University of Missouri Extension, which is solely responsible for the information provided and is wholly owned by the source. Informa Business Media and all its subsidiaries are not responsible for any of the content contained in this information asset.