Cadophora gregata formerly known as Phialophora gregata
Symptoms and Signs:
- brown to reddish-brown discoloration of stem pith
- “greasy” appearance of outside of stem
- foliar symptoms not always present, but when present include wilting and inter-veinal chlorosis and necrosis
- The pathogen survives on crop residue over the winter.
- Conidia (asexual spores) are produced in spring under cool temperatures.
- The fungus invades the root and breaks down the vascular tissue.
- It then colonizes the pith and vascular system and, depending on the pathotype, the leaves.
- Symptoms usually appear after pod formation.
- Host resistance- Few sources of resistance are available, so host resistance should be used in combination with other management strategies.
- Cultural practices- Crop rotations with non-hosts such as corn or small grains will help reduce the amount of inoculum present in the field. Deep plowing of crop debris can also help reduce BSR incidence up to 30% when compared to no-till fields.
- Early maturing varieties- Early maturing varieties may escape the yield reducing effects of brown stem rot in comparison to cultivars with later maturity or planting later in the season.
- Soil pH- Brown stem rot severity is higher when pH decreases. Modifying soil pH to close to 7.0 will reduce the risk of Brown stem rot, except when SCN is present.