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Content by Connie Strunk

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.

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.

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.

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.

Green cover crop growing within yellow wheat stubble.

Cover Crop Considerations When Dealing With Soybean Cyst Nematode

With the soybeans being harvested a little earlier than usual this year, some producers are finding themselves making management decisions that include cover crops. For soybean producers dealing with soybean cyst nematode in their fields, selection of cover crops is important since some of these can be hosts for soybean cyst nematode.

Harvested corn field with field pennycress throughout.

Soybean Cyst Nematode Management Plans Should Include Proactive Weed Management

While soybean cyst nematode can be managed through use of resistant varieties and crop rotation, presence of alternative weed hosts can negate the benefits of these practices by providing a host for soybean cyst nematode to continue to accumulate in the soil.

Left: A corn ear showing Gibberella ear rot symptoms. Right: A prematurely dried corn stalk split to reveal pith disintegration due to stalk rot.

Corn Ear Rots and Stalk Rots: The Last Issues To Check for in Corn Before Combining

Before combining corn, it is recommended to scout your field for corn ear rots and stalk rots. It is important to scout corn fields for these two issues in order to make timely decisions on corn combining.