While scouting wheat last week I observed several fields with small populations of true armyworms. This may seem unimportant as most wheat fields are nearing maturity. However, true armyworms don’t just defoliate leaves.
While scouting wheat fields throughout South Dakota, we have started noticing the presence of bleached heads scattered throughout many different fields. These discolored heads are the result of an infestation of the wheat stem maggot.
Bacterial leaf streak was observed in winter wheat fields scouted in Brookings County. Up to 40% yield loss can occur when severe bacterial leaf streak develops. Severely diseased heads may fail to give any marketable grain.
Recently SDSU Extension held their annual Wheat Walk program on May 25 and June 1, 2017. The Wheat Walk programs brought producers, Industry and SDSU Extension experts out and into wheat fields near Pierre, Wall, and Clark.
Leaf rust was observed in a few winter wheat fields at low levels. Most of the winter wheat is now flowering or past flowering and therefore a fungicide treatment may not be beneficial this time for leaf rust.
SDSU Extension will be hosting a tour of the Small Grain Crop Performance Trials (CPT) located near Ideal, S.D. The tour is set for June 19th at 5:00pm. This event is free and open to public.
Stripe rust continues to be found in several winter wheat fields mainly in areas that have had rainfall in recent days. Some of these fields have severe stripe rust developing. However, since it has been dry with warm temperatures growers are wondering if a fungicide is still necessary.
A few winter wheat fields scouted last week were found with symptoms caused by non-living (abiotic) agents. Some of the symptoms observed include physiological spots, yellowing lower leaves, and gray spots. Growers are wondering if these are diseases that something can be sprayed on to manage.
Several winter wheat fields were scouted last week and the main diseases observed were stripe rust and wheat streak mosaic. Powdery mildew was also observed in a few fields but at low severity. Stripe rust has now been confirmed in 5 counties including Brookings, Hand, Tripp, Union, and Stanley. One field in Stanley County was found to have a moderate level of stripe rust.
Barley yellow dwarf is starting to develop in winter wheat. Barley yellow dwarf is caused by the Barley yellow dwarf virus (BYDV). This disease usually becomes more distinct at flag leaf emergence. A typical symptom of Barley yellow dwarf is the purplish-yellow color of infected leaves, especially the flag leaf.