Wheat School: How T3 fungicide impacts winter wheat yield

Should Ontario winter wheat growers apply a T3 fungicide to protect the crop from fusarium infection?

That’s the question RealAgriculture’s Bernard Tobin and University of Guelph associate professor Dave Hooker tackle on this episode of the Wheat School.

When it comes to yield response, extensive research conducted by Hooker and his colleagues indicate that, on average, winter wheat will produce an extra 8.8 bu/ac when sprayed with a fungicide at the T3 timing.

Yield response, however, does vary significantly, according to the research: 25 percent of the responses produced yields of 11.5 bu/ac or greater; 50 percent yielded between 11.5 and 5.5 bu/ac; and 25 percent produced 5.5 bu/ac or less. Given today’s wheat prices — in the $15 bu/ac range — Hooker says its not difficult to rationalize or justify investing in a T3 fungicide.

Hooker says based on the data, his default position is to spray a T3 fungicide to suppress fusarium and reduce deoxynivalenol (DON) production… and then look at the weather and growing conditions to justify not spraying.

For growers to better understand the development of fusarium and to effectively assess disease risk and time application, Hooker looks closely at three critical periods or “windows of weather.” In the video, he shares how the inoculum production phase (4 to 7 days before heading); the infection phase (at flowering, and the 3 to 6 days after heading); and the following growth phase play key roles in fusarium management and the T3 decision.

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