Diseases & Disorders

All Diseases & Disorders Content

Green soybeans with yellowing throughout.

Bacterial Blight Developing In Some Soybean Fields

Bacterial blight was found developing in a few soybean fields scouted the week of July 19. Leaf tattering is a common symptom of bacterial blight and happens when expanding bacterial blight lesions coalesce and form large brown patches.

A soybean plant with wilting leaves due to stem canker surrounded by healthy soybean plants.

Stem Canker Developing in Some Soybean Fields

A few soybean fields are showing some wilting plants due to stem canker. The field entries and head rows are the most-impacted parts of these fields. The current dry conditions are stressing the plants and causing early development of the disease.

Yellow wheat with grey colored wheat heads.

Sooty Mold: A Saprophytic Fungi Observed in Wheat

While out crop scouting, sooty mold was observed in some South Dakota wheat fields. Sooty mold is a saprophyte, which can be easily mistaken for a disease caused by plant pathogens.

Three bean leaf beetles. From Left: Brown beetle with black spots on a green leaf. Yellow beetle with black spots on a green leaf. Red beetle with black spots on a green leaf.

Monitor Soybean for Bean Leaf Beetle Activity

Some of the bean leaf beetles we are currently observing in South Dakota may make up the population of overwintering adults. While these adults are in soybean, they can cause significant amounts of defoliation to the leaves.

Three soybean fields with yellowing issues due to potassium deficiency, iron deficiency chlorosis and soybean cyst nematode.

What Is Causing Soybeans to Yellow at This Time?

Recently scouted soybean fields were observed with yellowing plants, and one field was found to have plants dying prematurely. Learn some of the factors that may cause soybean plants to yellow at this time in the growing season.

A soybean field showing healthy soybean plants, but roots are infested with SCN. The top right corner has an in-set picture that shows a soybean root with white pear-shaped SCN female cysts.

Drought Conditions May Increase Soybean Cyst Nematode Population in Soil

Moisture stress coupled with above-normal temperatures have been linked with increased soybean cyst nematode populations in the soil. In order to keep populations in the soil below the yield-reducing levels, there are a few management practices which can be used.

From left: Wheat plants killed by common root rot. Wheat plants with bleached heads due to Take-all disease. Bleached wheat heads due to stem maggot feeding.

Differentiating Between Wheat Head Diseases and Disorders

Several diseases and disorders can develop in wheat heads. Learn the symptoms of several common disease and insect issues being observed in South Dakota wheat this growing season.

A wheat head showing the start of the flowering period. This growth stage is the best time to apply a fungicide to manage Fusarium head blight.

Use Fusarium Head Blight Risk Prediction Tools for Better Disease Management

Winter wheat has reached the flowering growth stage, which is a time of high risk for Fusarium head blight. By using disease prediction tools correctly, a producer can protect wheat from infection by applying a timely fungicide when the tools show moderate to high risk.

Stripe Rust Starting To Develop in Winter Wheat

Stripe rust was found in a few winter wheat fields scouted this week. The presence of a few plants with stripe rust indicates there is inoculum of this pathogen in the state.

Wheat tillers with lower leaves covered with tan-brown lesions. The ground beneath has wheat stubble from previous wheat crop.

Scout for Tan Spot in Winter Wheat

Tan spot was observed in a few winter wheat fields scouted recently. It is important to scout winter wheat for tan spot and other early diseases developing before deciding to apply an early-season fungicide tank mixed with herbicide.