Winter Wheat Update as of June 6, 2007

Winter wheat fields continue to advance rapidly. Earliest harvest will begin the first week of July. Fields in Essex/Lambton have pollinated and are moving beyond the Folicur window. In Huron/Bruce, much of the crop is heading now (June 6/7). Rainfall over the weekend (June 2/3/4) held many growers out of the field with Fusarium control products, while increasing the Fusarium risk. Optimal timing for Folicur or Proline is Day 2 (Day 0 is when 75% of heads have cleared the flag leaf). However, applications up to Day 5/6 can reduce Fusarium somewhat, and other leaf and head diseases will still be controlled. Check the website for your fusarium risk (link is available below).

Leaf disease levels remain very low in many fields but be on the look-out for leaf rust which has begun to appear in the province. Powdery mildew has continued to advance in about 20% of fields, with lesions just beginning on upper leaves. Short periods of high temperatures over the last two weeks do not seem to have been sufficient to stop mildew development on these varieties. Control is warranted in these fields.

Physiological fleck is evident at high levels in some fields. Barley Yellow Dwarf Virus (BYDV) symptoms continue to develop, particularly in the southwest where significant aphid numbers were present in May. Aphids are now being found in spring cereals in this region. With the higher levels of BYDV in winter wheat, spring cereals may be even more at risk. Scout! If control is warranted, (15 aphids/stem pre-heading, 50 aphids/stem post-heading) please contact Jen (519 272 4268) or Peter (519 318 7769) to set up some trials, and validate threshold levels. There is little Ontario data on the impact of aphid control in cereals.

Related Links:

• Weather INnovations Incorporated
  

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