FHB Update from MN, 07/06/17

Growth stages are ranging from Zadocks Growth stage 50 - 80 (inflorescence emergence to early dough development) across the state state. The warmer temperatures around the July 4th holiday, combined with rain events have seen growth stages advanced rapidly. With higher temperatures fields which are close to flowering will start to flower quickly and for those that have still to apply fungicide for Fusarium head blight control, fields should be watched closely so as not to miss the optimal spray timing at early flowering. Flowering in warm temperatures will be shorter, the period lasting 3-4 days. If no anthers are visible, open up spikelets to check for either green immature anthers, or if the plant has already flowered, embryonic grain development, which will be visible roughly four days after flowering.

The high humidity and warm temperatures are ideal for FHB development at this time. The risk model is currently trending moderate to high high risk in the North Central and North Eastern part of the state for moderately susceptible varieties, and largely moderate risk in these areas for moderately resistant varieties with a few hot spots of high risk in the next 24 to 48 hours.

Field observations again indicate that there is plenty of early awn infection and inoculum present in the Northwest part of the state, and Fusarium symptoms are now being reported in Southern MN where the crop is more advanced.

--Madeleine Smith, Plant Pathologist, University of Minnesota

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