Small Grains

All Small Grains Content

Green winter wheat leaf with yellow-orange strips indicative of stripe rust.

Stripe Rust Found in Winter Wheat at Low Severity

Stripe rust was observed in the crop performance trials at the Dakota Lakes Research Farm in Hughes County and at Ideal in Tripp County. At both locations, stripe rust was at a low severity.

Three wheat plants exhibiting disease symptoms. From left: Tan spot, powdery mildew, and Barley yellow dwarf.

Winter Wheat Diseases Update: Fungal Diseases and Barley Yellow Dwarf Developing

Tan spot and powdery mildew as well as barley yellow dwarf were found developing at low levels in winter wheat fields scouted the week of May 24, 2020.

Wheat plants exhibiting symptoms of tan spot and powdery mildew.

Does Early Fungicide at Tillering Result in a Profitable Yield?

Tan spot and powdery mildew pathogens are two residue-borne pathogens that can infect wheat early in the season. These diseases can lead to poor tillering, and their continued development can lead to yield loss.

Two diseased wheat plants side-by-side. The wheat heads on the left have ergot bodies throughout. The wheat plants on the right are infected with Fusarium head blight.

Assess Your Fields for Ergot and Fusarium Head Blight Before Harvest

The 2019 wheat harvest is well underway in South Dakota, with many acres of winter and much of the spring wheat crop left to harvest. To date, reports on yield and quality have been variable, depending on when the crop was seeded, weather conditions at important growth stages (such as flowering and grain fill) and disease pressure throughout the season.

Collage of four common wheat disease symptoms. From left: Tan spot, strip rust, stagonospora leaf blotch, and bacterial leaf streak.

Winter Wheat Disease Update: Leaf Diseases and FHB on the Increase

Winter wheat fields scouted last week show an increase in fungal leaf diseases and bacterial leaf streak. Among the fungal diseases, the most common leaf diseases are tan spot, Stagonospora leaf blotch, and stripe rust. The risk for Fusarium head blight has also started to increase in a number of areas in the state.

Oat leaf with water-soaked, brown longitudinal lesions on the top-half of the leaf blade.

Bacterial Blight Developing in Oats

Oats scouted in a few fields in the Eastern and South Central parts of the state were found with bacterial blight developing on the lower leaves. Plants infected have leaves with water-soaked brown longitudinal lesions in the top-half of the leaf. Severe symptoms can lead to premature leaf death.

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.