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Diseases & Disorders

All Diseases & Disorders Content

tall trees in the Black Hills

Tree Pest Alert

From seasonal issues and timely recommendations to disease diagnosis and expert advice, the Tree Pest Alert is a trusted resource for selecting, planting and caring for trees and shrubs all year round.

Two broccoli plants exhibiting early black rot symptoms.

Black Rot of Brassica Crops

Black rot is an uncommon, but devastating bacterial disease in South Dakota that can develop during extended periods of hot and wet weather, leading to rapid and widespread crop loss.

Swarm of mosquitoes.

West Nile Virus Update: October 16, 2025

As of October 16, 2025, the South Dakota Department of Health reported 86 human cases of West Nile virus from Aurora, Beadle, Bon Homme, Brookings, Brown, Charles Mix, Clay, Codington, Corson, Douglas, Grant, Gregory, Haakon, Hamlin, Hand, Hughes, Hutchison, Hyde, Lawrence, Lincoln, Marshall, Meade, Miner, Minnehaha, Pennington, Roberts, Sanborn, Spink, Stanley, Todd, Union, Walworth, and Yankton counties.

Dried corn growing in a field with visible damage and molding.

Mycotoxins: Should you be concerned?

Environmental stress caused by the weather or damaged crops increases the potential for mold and mycotoxin development. Learn some answers to common questions about mycotoxins and how to manage them.

Swarm of mosquitoes.

West Nile Virus Update: September 26, 2025

As of September 26, 2025, the South Dakota Department of Health (SD DOH) reported 74 human cases of West Nile Virus from Aurora, Beadle, Bon Homme, Brookings, Brown, Charles Mix, Clay, Codington, Corson, Douglas, Grant, Gregory, Haakon, Hamlin, Hand, Hughes, Hutchison, Hyde, Lawrence, Lincoln, Marshall, Meade, Miner, Minnehaha, Pennington, Roberts, Sanborn, Spink, Stanley, Union, Walworth, and Yankton counties.

Swarm of mosquitoes.

West Nile Virus Update: September 10, 2025

As of September 10, 2025, the South Dakota Department of Health (SD DOH) reported 59 human cases of West Nile virus from Beadle, Bon Homme, Brookings, Brown, Charles Mix, Codington, Corson, Grant, Gregory, Hamlin, Hand, Hughes, Hutchison, Hyde, Lawrence, Lincoln, Marshall, Meade, Miner, Minnehaha, Pennington, Sanborn, Spink, and Walworth counties.

Gardeners browsing a tablet computer while visiting a garden center.

Home Horticulture Resources for Gardeners

Horticulture is the branch of plant agriculture dealing with garden crops. In addition to our website, there are many horticulture resources available on the web to provide research-based information to help every gardener succeed.

Two white flowers with green leaves. The first flower has an abnormal fused bloom.

Fasciation: What’s going on with my plant?

Fasciation is a malformation of plant parts commonly manifested as enlargement, flattening or cojoining. The abnormal growth of plants can be uniquely puzzling and beautiful at the same time.

A group of brown cattle foraging in a green field.

Prussic Acid Poisoning

As the first frost date approaches, producers often have concerns about the risk of prussic acid poisoning in livestock. Certain forage plants, especially sorghums and related species are associated with an increased risk of death loss because of prussic acid poisoning.

Swarm of mosquitoes.

West Nile Virus Update: September 3, 2025

As of August, the South Dakota Department of Health indicated that West Nile Virus positive mosquito pools have been detected in Beadle, Brookings, Brown, Codington, Hughes, Lincoln, and Minnehaha counties.