Even though the seeding of winter wheat in northern Illinois will be delayed in most situations, certain cultural practices and management decisions are critical in growing this crop.

By now, seed has been purchased; but if not, select adapted, high yielding varieties that have scab and leaf disease resistance. Variety information is available at http://vt.cropsci.illinois.edu/wheat.html or in the booklet titled Wheat Performance in Illinois Trials-2009 available at the above web site or from local University of Illinois Extension offices.

The Hessian fly-free date has been used as a guide for seeding date. These dates are listed in the Illinois Agronomy Handbook, 24^th Edition, available at Extension offices and on-line at https://pubsplus.uiuc.edu/C1394.html The dates range from September 17-21 for the northern three tiers of Illinois counties to October 9-12 in far southern Illinois. In addition to preventing insect (including aphids) and disease problems, the date is also important for winter survivability and yield.

University of Illinois data indicates that yields often decline little with planting delays for the first 10 days after the fly-free date. From 10 to 20 days late, yields decline at the rate of 0.5 to 1 bushel a day. The loss increases to 1 to 2 bushels per day from 20 to 30 days late, with sharper declines in northern Illinois. Wheat planted a month after the fly-free date typically yields two-thirds to three-quarters of normal, and this is considered about the latest practical planting date.

Studies have shown that highest yields required seeding rates of 35 to 40 seeds per square foot or about 1.5 to 1.7 million seeds per acre. If there are 15,000 seeds per pound, then 100 pounds of seed contain 1.5 million seeds. Increase the seeding rate by 10 percent for each week of delay in planting, starting two weeks after the fly-free date. This will help compensate for reduced fall growth and spring tillering.

Optimum planting depth is 1 to 1.5-inches. Shallow planting can result in more winter injury. It is important to have good seed-to-soil contact and the crown of the plant needs to be ¾ - to 1-inch below the soil surface. It is best if the plant can grow to about the 3-leaf stage and form two to three tillers in the fall.

Wheat should not be planted following wheat, as volunteer wheat can serve as "the green bridge" for diseases such as wheat streak mosaic virus, which is vectored or carried by the wheat curl mite. Research at Monmouth has shown that wheat yields 3 to 4 bushels more following soybean than following corn.

Wheat receives 10 pounds per acre of nitrogen credit when following soybean. When following a good stand of alfalfa, the credit would be 30 pounds per acre. Since the amount of nitrogen needed for good fall growth is modest, 20 to 30 pounds of nitrogen is recommended. Spring nitrogen (applied at early green-up) recommendations are based on the soil organic matter and the amount of nitrogen that one bushel of wheat will "buy", as shown in Table 9.2 of the Illinois Agronomy Handbook, 24^th Edition.

Phosphorus and potassium should be applied based on a current soil test and past yields. Maintenance fertilizer or the amount removed for each bushel per acre is 0.90 pound P₂O₅ and 0.30 pound K₂O.

Fungicide seed treatments are an inexpensive way to help ensure improved stands and better seed quality. Each fungicide active ingredient has pros and cons; thus premixed products are common. These treatments may be more beneficial for later planted wheat.

Insecticide seed treatments have increased yields in northern Illinois by 1.7 bushels per acre compared to about 6 bushels per acre in southern Illinois. Early-planted wheat is more likely to benefit from insecticide seed treatment.

Further details are included in Chapter 4 of the Illinois Agronomy Handbook, 24^th Edition.