Small Grains

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Winter wheat plants at the tillering growth stage with leaves yellowing as a result of wheat streak mosaic virus infection.

Wheat Streak Mosaic Developing in Winter Wheat Fields

A few winter wheat fields in central South Dakota have been found with wheat streak mosaic disease. Incidence of this disease varied from a few plants to large portions of the field with yellowing leaves.

a strand of oats in a field

2020 Plant Disease Summaries for Small Grains

A number of field trials were implemented in the 2020 growing season with the general objective of assessing various disease management practices suitable for South Dakota growers and the Great Plains.

Diseases on three different wheat plants. From the left: powdery mildew, fusarium head blight, and leaf rust.

Winter Wheat Diseases Update

Powdery mildew, fusarium head blight and leaf rust were observed in a few winter wheat fields recently scouted. The recent rainfall showers and warm temperatures have favored these diseases to develop in winter wheat.

Map of South Dakota showing Fusarium head blight risk. Green indicates low risk, yellow moderate risk, and red high risk. Most of the state is green except for scattered, yellow areas within Edmunds, Faulk, Hyde, Hand, Buffalo, Jerauld, Brule, Aurora, Turner, Lincoln, McCook, Lake, Brookings, and Kingsbury counties. Some red, high risk areas are in Buffalo, Brule, Hyde, and Minnehaha counties.

Fusarium Head Blight Predicted Risk for Spring Wheat

Most of the spring wheat is at or will soon be at flowering. One disease that can develop in wheat at this growth stage is fusarium head blight (FHB or scab).

Yellow and brown streaks on a winter wheat leaf indicative of bacterial leaf streak symptoms.

Bacterial Leaf Streak Developing at Low Level in Winter Wheat

A few winter wheat fields were found with bacterial leaf streak starting to develop at low levels. Bacterial leaf streak is usually observed starting from flag leaf growth stage. It can be severe on the upper leaves when there is prolonged leaf wetness resulting from frequent rains.

A few wheat plants showing heavy yellowing mosaic symptoms due to Wheat streak mosaic virus.

Wheat Streak Mosaic Disease Developing in Winter Wheat

Although the majority of winter wheat in the state is rated good to excellent in the recent USDA-NASS report, a few winter wheat fields in Central South Dakota have been diagnosed with wheat streak mosaic disease (WSMD) caused by wheat streak mosaic virus (WSMV).

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.