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Symptoms of rust infection on wheat blades. Left: Stripe rust. Yellow pustules are arranged in a linear fashion on the wheat blade. Right: Leaf rust. Orange-brown pustules are randomly distributed on the leaf.

Stripe Rust and Leaf Rust Developing in Winter Wheat

Stripe rust and leaf rust were found in winter wheat plots at the SDSU research farm in Aurora. Observation of these two rusts indicates that we have inoculum in our area, therefore winter wheat fields should be scouted until wheat is done flowering.

Two, dark green aphids on a bright green leaf.

Aphid Populations Being Observed in Wheat

During the past couple of weeks, reports of aphid populations in wheat fields have slowly been increasing. Typically, the initial aphid populations are observed earlier in the season, but the 2019 spring may have delayed infestations.

A color-coded map of South Dakota. The majority of the map is green, with a small patch of yellow and some specs of red in the East, South Central part of the state.

Use the Scab and Leaf Disease Forecasting Tools to Decide on Fungicide Application in Wheat

Fungicide application in winter wheat has consistently shown to prevent yield loss caused by fungal diseases. However, in some cases, a fungicide application may not always result in a profitable yield when disease pressure is low. Disease forecasting tools can aid fungicide application decisions and hence improve on the profitability of fungicide application.

winter wheat blade with brown to tan colored lesions with water soaking around them.

Bacterial Leaf Blight Developing in Winter Wheat

Recent winter wheat scouting found bacterial leaf blight developing in some fields. Bacterial leaf blight is caused by the bacteria, Pseudomonas syringae pv. syringae. The disease develops under frequent rains between 59 and 77 degrees Fahrenheit.

wheat field

2018 Field Plot Summaries for Wheat Disease Management Trials

The wheat disease management field experiments conducted in the 2018 growing season evaluated several experimental and commercially available fungicides for managing foliar, head or root diseases of spring wheat. Foliar and spike/head diseases incidence and severity were assessed. The field experiments were implemented at Volga Research Farm and Northeast Research Farm (NERF) near South Shore, SD. Results of the same experiment may vary between Volga and Northeast due to environmental differences between the two locations.

Wheat heads with extreme white-yellow bleaching.

Wheat Stem Maggots Observed in S.D. Wheat

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.

Barley yellow dwarf developing in winter wheat.

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.

A field of emerging winter wheat in early spring.

Winter Wheat Breaking Dormancy Early

A threshold indicator for winter wheat emergence is to consider average temperatures over a 14-day period. When that 14-day average temperature is equal to or above 5°C, or 41°F, then hard red winter wheat can break dormancy.

Small white mites crawling on a blade of wheat.

Managing Wheat Curl Mite

Wheat curl mite is one of the more difficult pests to manage in wheat. This is in part due to the limited options available for preventing populations from infesting a field and rapidly reproducing.

yellowed wheat field

Wheat Streak Mosaic Virus Management: Plan ahead before planting this fall

Have you had a history of moderate wheat streak mosaic disease in your field? Do you plan on planting wheat into wheat stubble or wheat fallow? Have your neighbors had wheat streak mosaic disease outbreaks in the recent past? If you answered yes to any of these questions, you need to incorporate wheat streak mosaic control principles into your management plan before planting winter wheat this fall.