Cause Fusarium sp. is suspect. Fusarium oxysporum was found repeatedly during 2012 and 2013 in association with dying plants in Oregon seed fields. The fungus is soilborne and can survive in soil, often in plant debris, for at least several year as durable resting spores known as chlamydospores. The fungus can be spread by infested equipment or windborne or waterborne movement of infested soil. Fusarium also produces spores, which can be moved with air currents or water.
Symptoms Wilting becomes evident as coneflowers begin flowering; portions of the shoot or the entire plant can die. Affected individual plants were observed in the earlier part of flowering, as the season progressed, large clusters of dead and dying plants were found.
Cultural control
- Avoid establishment of seed fields in soils with high levels of plant residues or organic amendments.
- Remove and destroy all affected plants, including roots.
Biological control
- Bexfond at 7 to 28 fl oz/A. O
- Tenet WP at 2.5 to 5.0 lb/A at sowing will suppress certain fungal pathogens including Fusarium, Rhizoctonia, and Pythium spp. See label for specific application types and timings. 1-hr reentry. O