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Corn Diseases

All Corn Diseases Content

aerial view of South Dakota farm and surrounding land

Pest & Crop Newsletter

SDSU Extension publishes the South Dakota Pest & Crop Newsletter to provide growers, producers, crop consultants, and others involved in crop production with timely news pertinent to management of pests, diseases, and weeds in South Dakota.

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.

Tan-gray Goss’s bacterial blight lesions were observed in scouted corn fields.

Goss’s Bacterial Wilt and Blight Developing

While out scouting corn fields (the week of August 11, 2020) Goss’s bacterial wilt and blight was found starting to develop in a number of fields.

Green corn plant with abnormal tassel growth.

Crazy Top Disease Developing in Corn

Crazy top disease was observed in a few fields in the Southeast counties in the state. This disease develops in corn that is flooded or under full water saturation when corn has not reached the four-to-five leaf stage.

Three corn diseases. From left: Southern Rust, Bacterial Leaf Streak, and Eyespot.

Southern Rust, Bacterial Leaf Streak, and Eyespot Are Developing in Corn

Southern rust was found in Yankton County, bacterial leaf streak was found in Brule County, and eyespot was found in several fields and counties the week of July 27, 2020.

A mostly green corn leaf that is in brown to yellow markings caused by southern rust.

Is a Fungicide Applied at Tasseling Profitable in Corn?

Corn is currently at tasseling/silking across the state. This is usually the growth stage when a fungicide is applied to control fungal diseases.

corn field with sunrise in the background

2019 Corn Fungicide Field Trials Summary

This document contains results of corn field trials conducted during the 2019 growing season to evaluate foliar fungicides to manage various corn diseases.

Sunny field with large puffy clouds and blue sky

2020 South Dakota Pest Management Guides Released

August 25, 2020

The 2020 South Dakota Pest Management Guides are now available for free on the SDSU Extension website.

Gibberella ear rot and Fusarium spp. symptoms on two corn ears.

Gibberella and Fusarium Ear Rots Developing in Corn

Corn ear rots are one of the last diseases to scout for in the corn growing season, and sometimes they are ignored or forgotten entirely. Ear rots can cause yield loss in the form of grain quality at harvest, but also cause losses during storage.

A corn field with several plants showing symptoms of stalk rot.

Assess for Corn Stalk Rots

Several corn fields are beginning to show stalk rot and top dieback symptoms. Stalk rots cause the entire plant to die prematurely, which can lead to plants lodging under windy conditions making harvesting problematic.