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Content by Connie Strunk

Soybean leaves with small, white lesions with red-to-purple halos throughout.

Frogeye Leaf Spot Developing in Soybeans

Frogeye leaf spot, also known as Cercospora leaf spot, was found in several soybean fields scouted the week of August 19, 2019. Frogeye leaf spot is characterized by irregular to circular lesions, which are tan-to-gray in color with reddish-purplish borders.

Corn leaf with “cigar” shaped tan to gray lesions throughout.

Northern Corn Leaf Blight Developing in Corn

Northern corn leaf blight was found in a few corn fields scouted recently. The disease was found at very low severity, except occasionally when an individual plant was found with several lesions on one leaf.

A corn field with several plants displaying long, tan to gray lesions on their leaves.

Goss’s Bacterial Blight Beginning to Show Up in Corn

Goss’s bacterial blight was found in a few corn fields scouted the week of August 5, 2019. The severity ranged from low to moderate, where at least 25 percent of the leaf area was killed by the bacteria infection on several plants. The disease is characterized by long, tan-gray lesions with wavy margins found in the center of the leaf or along the edges of the corn leaf blade.

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.

Symptoms of three common corn diseases. From left: anthracnose leaf blight, common rust and eyespot.

Is a Fungicide Needed for Developing Corn Diseases?

Corn is starting to tassel in several locations across the state. This is also the growth stage when a fungicide may be applied to control fungal leaf diseases. Diseases currently starting to develop are: anthracnose leaf blight, common rust and eyespot.

A green soybean plant with purple and white flowers begining to develop.

Current Weather Conditions Are Conducive White Mold Development in Soybeans

Frequent rains and overcast conditions continue to occur in South Dakota’s main soybean growing counties. These conditions favor white mold development. In some of these counties, soybean is already at R1, which is also the best timing for fungicide application targeting white mold control.

Green blades of wheat with brown, rust-like spots throughout.

Diseases in Winter Wheat Imply High Inoculum for Spring Wheat

Winter wheat is past the need for an in-season fungicide application. However, many spring wheat fields are yet to flower, making them prone to disease development. A few diseases, including leaf rust, stripe rust, and Fusarium head blight have developed in winter wheat. This implies that there is enough inoculum available for these diseases to develop in spring wheat; especially East River, where rainfall has been frequent.

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.

A collection of empty pesticide and herbicide containers.

What to Do With Unusable Home and Garden Pesticides

As a gardener or homeowner, you may be wondering what you can do with your leftover pesticide products (including herbicides, insecticides, and fungicides), or maybe you bought a new home and the garage or basement is full of mysterious containers with no labels. If products are stored in garages or other areas with a lot of temperature changes, these products may become entirely unusable. So what to do?

A green soybean pod with frogeye leaf spot symptoms. The pod is partially open to reveal developing seed at the end of the pod with frogeye leaf spot symptoms developing.

Frogeye Leaf Spot of Soybean

This fact sheet is about a soybean disease that is increasingly becoming more severe in South Dakota. Moreover, fungicide resistance for this pathogen has been detected in South Dakota.