What a lousy year for wheat! We were challenged last fall to plant wheat on time due to untimely rainfall. Despite the late planting, wheat in most of west central Ohio looked pretty good into the heading process. When rains came numerous days during the flowering stage, cooler temperatures left us with the hope that we might avoid some of the Fusarium head blight fungus floating around. Any hope of a decent yield with good quality was buried last week with data collected during our wheat head scab field assessments.

Dr. Pierce Paul, Ohio State University plant pathologist reported late last week that our surveys of wheat fields across the state show that the incidence of head scab ranges from about 4 to 60 percent, meaning that between 4 and 60 heads out of every 100 heads have some scab. Head scab is a disease caused by the fungus Fusarium graminearum or Gibberella zeae (two names for the same fungus). Scab develops best when wet, humid weather occurs when the wheat is flowering. The disease causes shriveled and lightweight kernels, reducing grain yield and test weight. In addition, the fungus also produces a toxin called vomitoxin that is harmful to humans and livestock. So, the effects of scab can be devastating, lower yields, lower test weights, and toxin contamination equals price discounts or complete grain rejection at elevators.

Many, if not most of the wheat fields in our area have turned color, making it difficult to determine whether the scab fungus or glume blotch have infected the wheat head.

As we rapidly approach wheat harvest, remember that turning up the air on the combine will help blow out scab infested kernels. These kernels are lighter than wholesome kernels. If there is any inclination to feed the grain, be sure to have it tested for vomitoxin levels prior to use.

More than a handful of area farmers are hoping for a long enough “no rain” window this week to finish planting soybeans, touch up thin spots, finalize first cutting hay harvest and sidedress corn.
If planting soybeans, keep in mind that late planting reduces the cultural practice options for row spacing, seeding rate, and variety maturity. The row spacing for June planting should be no greater than 7.5 inches. Appropriate seeding rates for the first half of June were about 200,000 to 225,000 seeds per acre. For the last half of June, 225,000 to 250,000 seeds per acre is recommended to promote canopy closure for sunlight interception and weed control. Higher populations will also encourage taller plants and the first reproductive node set higher to aid in harvest efficiency.

Relative maturity (RM) has little effect on yield for plantings made during the first three weeks of May, but the effect can be large for late plantings. During the first half of June, a four-day delay in planting delays physiological maturity about one day. In the last half of June, it takes a five-day planting delay to delay physiological maturity one day. As planting is delayed, yield potential goes down.

When planting runs late, the rule of thumb is to plant the latest-maturing variety that hopefully reaches physiological maturity before the first killing frost. The reason for using late-maturing varieties for late planting is to allow the plants to grow vegetatively as long as possible to produce nodes where pods can form before vegetative growth is slowed due to flowering and pod formation. More nodes equates to more pods and more yield. Varieties with an earlier relative maturity will mature earlier but will produce reduced yields.

The views and opinions expressed in this column are those of the author and not necessarily those of Farm World. Readers with questions or comments for Roger Bender may write to him in care of this publication.