With the risk of wheat midge being high in the north central and northwestern regions of North Dakota for 2011, producers can mitigate damage by planting early. Early planting is the most useful cultural control method for hard red sprng wheat. Early planting is not as effective with durum because dururm wheat varieties are later maturing than spring wheat.
By planting early maturing wheat varieties, wheat midge infestation is minimized because the crop heads adn flowers before peak emergence (before 200 degree Days (DD)). Planting early maturing varieties will not help if planting is delayed and occurs during the time frame (200-600 DD) that causes teh wheat to head as wheat midge is emerging. Degree days are used to help identify the high risk planting windo for hard red spring wheat. Wheat reaches heading state at 1,000 DD (when using the same wheat midge DD accumulations). The following guidelines are provided to identify at-risk planting dates for wehat midge infestation in hard red spring wheat (HRSW). We anticipate that 200 DD will be reached by mid-May in the northern tier of North Dakota.
Wheat Midge Degree Days Used as a Guideline for HRSW Risk Assessment
HRSW planted PRIOR to accumulation of 200 DD will head before wheat midge emerge.
HRSW planted FROM 200 to 600 DD will head at the time wheat midge is emerging.
HRSW planted AFTER 600 DD will head after peak emergence and should be at low risk to wheat midge infestation (higher risk of frost).
The wheat midge forecast maps are available here.