Bean Binoculars Incident

Fungicide phytotoxicity was scouted in R4 (full pod) growth stage soybeans approximately 1 month after an application of a fungicide containing prothioconazole. The fungicide was applied at 2 gal. per acre carrier volume using the standard rate based on label directions. The phytotoxicity may be due to high temperatures during the application. Approximately 50-75% of the site showed damage. Fungicide phytotoxicity may appear as interveinal chlorosis and in severe cases leaf tissue may become necrotic. Symptoms usually appear in the upper canopy of soybean ~21-28 days post fungicide application.

Verify the symptom is in fact fungicide phytotoxicity by ruling out diseases that cause similar symptoms, like sudden death syndrome, red crown rot (not currently found in Nebraska) and brown stem rot. Look at your fungicide application history to determine when the application was made, paying special attention to any additional stress that would have been on the plants during that time. Once verified, no management action is required. Yield loss due to this issue has not been reported.