Diseases & Disorders

All Diseases & Disorders Content

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.

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.

Left: A close-up of two wheat leaves showing light yellow streaks, a symptom of wheat streak mosaic virus. Right: Winter wheat leaves with small dark brown lesions surrounded by a yellow halo, a symptom of tan spot.

Winter Wheat Disease Update: Wheat Streak Mosaic and Tan Spot Developing at Low Level

Winter wheat fields scouted the week of May 27, 2019 in South Central South Dakota were found with wheat streak mosaic virus and tan spot developing at very low levels. Both diseases were found in non-rotated wheat fields.

Alfalfa shoots with top leaves showing yellow patches interspersed with green patches, symptoms for Alfalfa mosaic virus

Alfalfa Mosaic Developing in a Few Alfalfa Fields

In South Dakota, alfalfa fields that were recently scouted were found to be infected with Alfalfa mosaic virus (AMV) at a very low incidence. AMV is a common virus in alfalfa that can also infect soybeans.

Winter wheat blades with lesions with a dark brown center and yellow margin surrounding the lesion.

Diagnosing Early Diseases in Winter Wheat

Winter wheat progress is relatively behind the five-year average given the long winter season and low spring temperatures. However, it is important to scout and diagnose early-season diseases in winter wheat to determine the need for an early season fungicide.

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.

Field with field peas and blue sky with fluffy white clouds

An identification guide of common Diseases of Dry Peas in South Dakota

A guide depicting common diseases of Dry Peas in South Dakota

An empty grain bin full-air floor is plugged by insect webbing.

Stored Grain Pests: Spring Insect and Disease Issues

Grain storage is a key component in getting your crop to market. Aside from watching bins for spoilage, moisture, and temperature changes, make sure you are looking for signs of pest infestation.

Soybean seed drill. Courtesy: United Soybean Board

Fungicide Seed Treatment Considerations for 2019

With the excessive soil moisture and flooding that has occurred throughout South Dakota, growers may be thinking about using a fungicide seed treatment this planting season.