Cause Fusarium spp. that are common saprophytes on umbelliferous crops as well as some weeds and other cultivated plants. These soilborne fungi can overwinter as chlamydospores and hyphae in soil or plant debris and on living plant roots. Conidia produced on hyphae are spread by wind and move with soil.
Symptoms Small reddish-brown regions of dry rot develop on the sides of storage roots; other microbes may subsequently invade, and larger areas of dry rot can develop. Damage is typically minor, and no foliar symptoms are apparent. Secondary roots may exhibit a grayish coloration due to root rot.
Cultural control
- Long rotations will reduce the population of chlamydospores in soil.
- Select well-drained fields. Avoid fields with excessive soil compaction.
- Burying infected plant debris will hasten breakdown of plant material and expose the pathogen to antagonistic soil microbes.
- Control weeds and insect pests that damage roots.
Biological control
- Bexfond at 7 to 14 fl oz/A. O