Early Season Sunflower Rust Can Pose Severe Problems

By: Robert M. Harveson

Rust, caused by the fungal pathogen Puccinia helianthi, is not a disease that we see every year. However, if it occurs early in the season, it can pose severe disease problem of sunflowers in Nebraska, particularly in irrigated fields.

Signs of rust observed this spring in volunteer sunflowers at the Panhandle Research and Extension Center are a signal that conditions are conducive for disease to occur. Sunflower growers should destroy volunteer and wild sunflowers, be prepared to scout fields earlier than normal this year, and be prepared to treat with fungicides to reduce the damage to crops.

The rust pathogen has a very complex life cycle consisting of five distinct spore stages—all of which occur on sunflower.