Winter Wheat Update as of May 24, 2007

Winter wheat fields are advancing quickly past the flag leaf stage. Fields in Essex/Lambton are at the mid-boot stage (Zadok's 47-48); advanced fields will head on the weekend (May 26/27). In Huron/Bruce, advanced fields are at flag leaf (Zadok's 39) while most fields there are at the flag leaf just emerging stage (Zadok's 36-37). Over the next couple of weeks, depending on where you are in the province, it will be time to spray for fusarium. Make sure to scout your fields to optimize spray efficacy. Optimal timing for Folicur or Proline is Day 2 (Day 0 is when 75% of heads have cleared the flag leaf). Trials by Dr. David Hooker indicate potential yield and quality improvement with Proline over Folicur, but does it cover the additional cost? The only way to know is with lots of field trials! Contact Peter Johnson (519 318 7769) if you have interested growers!

Vigorous stands have begun to outgrow their physiological fleck symptoms. In poor stands, the flecks are still obvious, and in severe cases the flecks have become necrotic, and will impact yield. Powdery mildew is present in the lower canopy in 60-70% of fields. In very dense canopies, the fungus is moving into the middle of the canopy. Because powdery mildew growth stops above 25ºC, this week's warm weather should stop disease progression. Septoria levels remain low. No rust has been found to date. Barley Yellow Dwarf Virus symptoms are showing in an increasing number of fields (see previous article titled "Yellow Wheat - Possibly Barley Yellow Dwarf" in this issue.)

Table 1. Weeds as observed in Essex/Lambton and Huron/Bruce

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