This is the first small grains disease & pest update of the 2026 growing season. The scouts are receiving their training this week and will start their weekly routes next week. Meanwhile, warmer-than-average daytime high temperatures are pushing crop development, and the earliest-seeded spring wheat, spring barley, and oats are already at the heading stage across the southern third of the state. That means it's time to make fungicide decisions to suppress Fusarium Head Blight (FHB) and control any other fungal diseases that may be present. Leaf wetness duration is key to allowing fungal infections to take hold.
The latest US Drought Monitor, issued yesterday, has much of Minnesota classified as abnormally dry or in a moderate drought. While the drought monitor does not tell whether dews stay around long enough to reach the minimum leaf wetness durations, the current map is somewhat informative if you overlay the NDSU Small Grain Disease Forecasting output for individual weather stations; only in the white parts of the state are there one or two days in the past week to ten days where leaf wetness durations were long enough for tan spot, Septoria, or leaf rust to develop.
Meanwhile, the risk of Fusarium Head Blight has been low across the state for the past ten days, according to both the NDSU model and the national Fusarium Risk Tool. The Fusarium Risk Tool's 2 to 6-day outlook is trending towards moderate risk for susceptible spring wheat varieties.
So what should your decision be if your crop is fully headed (barley and oats) or reaching anthesis (winter wheat, spring wheat, and winter rye) in the next few days or early next week?
Oats - if you did not apply a fungicide to control crown rust when the flag leaf had just fully extended, apply a fungicide to protect the crop against crown rust for the remainder of the season. There is little incentive/need to switch to a premium fungicide to also try to suppress FHB, given that the overall risk appears to be relatively low
Spring barley - apply a fungicide to control net blotch on varieties rated susceptible or very susceptible to net blotch.
Winter wheat - apply a fungicide if you find either tan spot or Septoria present in the lower canopy or if your variety is rated very susceptible to FHB. There is little incentive to use one of the premium fungicides to suppress FHB
Spring wheat - apply a fungicide if you find either tan spot or Septoria present in the lower canopy or if your variety is rated very susceptible to FHB. There is little incentive to use one of the premium fungicides to suppress FHB.
Winter rye - Only consider a fungicide if you can find powdery mildew in the lower canopy. There is little incentive to use one of the premium fungicides to suppress FHB.
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| Picture 1 - US Drought Monitor's drought ratings for Minnesota as of June 2, 2026 (white=none, yellow=abnormally dry, tan=moderate drought, orange=severe drought) |
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