Southern rust confirmed in parts of Nebraska
Fungicides for Rust Diseases
Timely fungicide applications can be very effective at controlling rust diseases in corn. Keep in mind that systemic fungicides can provide protection from disease spread for about 21 days. Applications that were made several weeks ago likely are no longer providing protection from fungal foliar diseases. Pay close attention to the label restrictions on the most recent version of the product’s label as changes have been made for pre-harvest intervals and other use parameters.
A list of foliar fungicides labeled for use on corn in Nebraska and their characteristics are summarized in Foliar Fungicides for Corn Grown for Grain on page 215 in the 2012 Guide for Weed Management with Insecticides and Fungicides. Results from foliar fungicide trials conducted in Nebraska are available at the UNL Extension Plant Pathology team’s website, Plant Disease Central, under Management Trials for Corn. These results were gathered from trials with natural infestations of gray leaf spot and sometimes southern rust.
click image to zoomPhotos courtesy of Casey Schleicher, UNLFigure 3. Goss’s bacterial wilt and blight is an ongoing problem in some Nebraska corn fields. Be sure to look for the small dark “freckles” and glossy “exudate” on the leaf lesions. Goss’s Bacterial Wilt and Blight
Goss’s wilt (Figure 3) continues to be confirmed in samples submitted from across the state. Make sure that you know the identity of the disease(s) in your field before making a fungicide application, since Goss’s wilt and other diseases are also present right now and can’t be directly managed with foliar fungicide applications.
CropWatch has recently featured several articles on Goss’s bacterial wilt and blight, which may be helpful:
- Goss's Wilt of Corn Confirmed in Multiple Locations across Nebraska
- Goss's Wilt of Corn Continues to Develop across Nebraska