Life Cycle: The fungus enters the head through wounds produced by hail, birds or insects. In wet and hot weather the infection spreads throughout the head.
Damage: Losses can be significant and some fields have been reported to be totally infected. In NSA field surveys, Kansas fields had a high incidence of 20% in 2007 compared to 5% in 2006 and 1.5% in 2005. Other states reporting damage of 5% or more in one or more of the survey years are Texas and Colorado. The 2007 damage in Kansas may likely be associated with extremely high sunflower moth incidence.
Economic Thresholds: This is not well defined since there is not a fungicide treatment available.
Scouting Method: Not available
Management: There is no fungicide treatment available for this fungus. Good head insect control such as the sunflower moth is believed to be the primary management factor of the disease.
Research: Very limited work has been done on the other headrots.
Photos: Visit the Photo Gallery.
Another resource about Diseases can be found in the Archive section of The Sunflower magazine.
Source: NDSU Extension Bulletin 25 Sunflower Production Handbook, NDSU Extension Service, September 2007 and High Plains Production Handbook June 2005