In the first week of scouting, all three scouts did not report anything noteworthy in the wheat fields they visited. And except for a few aphids and a single lesion of halo blight in a single plot of a new Canadian oat variety, the yield trials near Rochester and Rosemount told the same story. Halo blight is caused by the bacterium Pseudomonas syringae pv. coronafaciens and is primarily a seedborne disease that is rarely, if ever, found in Minnesota.
However, that same day, true armyworms were reported in several rye cover crops in SE Minnesota. This morning, a similar report was fielded from the SW part of the state. This indicates that, while maybe not widespread, true armyworms have migrated north, and locally numbers may be high enough to warrant treatment. To scout for armyworms in small grains, part crop, and look for fecal pellets on the soil surface. If present, look for larvae under soil clumps and plant residues. Start scouting on the south edges of fields and/or areas where grain has lodged. The threshold for all small grains is 4 or more worms per square foot.
This week's forecast remains very favorable for small grains with highs across the state in the mid seventies to lower eighties and nighttime lows in the fifties and low sixties. Last week's intermittent rains are resulting in longer leaf wetness duration periods, and the number of days favorable for tan spot, Septoria, and rust is starting to reach six or more days in the past ten days at some of the NDAWN/MAWN weather stations. Likewise, the risk of FHB is increasing and has reached a moderate risk for the most susceptible spring wheat varieties at those same locations. Therefore, the advice remains more or less the same as last week.
Oats - If you did not apply a fungicide to control crown rust when the flag leaf had just fully extended, apply a fungicide at Feekes 10.5 (fully headed) 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 at Feekes 10.5 (fully headed) to suppress FHB and control net blotch on varieties rated susceptible or very susceptible to net blotch. There is little incentive to use one of the premium fungicides to suppress FHB.
Winter wheat - Apply a fungicide at Feekes 10.51 (beginning of anthesis) 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 at Feekes 10.51 (beginning of anthesis) 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.
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