See:
Corn (Zea mays) - Bacterial Stalk Rot
Corn (Zea mays) - Crown and Stalk Node Rot
Cause Several fungi can cause stalk rots. The principal ones are Fusarium verticillioides and Pythium spp. They can overwinter on corn crop residue or in soil, and Fusarium propagules may be carried on seed. Incidence of the root and stalk rot phase is associated with moisture stress and over fertilization with nitrogen. Stalks or roots previously injured by cold or insects are especially susceptible to attack by these fungi.
Symptoms Brown decayed spots appear on roots, and the disease moves into the crown. Root rot is usually, but not always, accompanied by stalk rot. Root and stalk rot causes premature dying, and rotted stalks break over as the crop matures. Fusarium stalk rot develops a whitish pink to salmon discoloration of the pith. A characteristic of Pythium stalk rot is that the internode just above the soil line becomes brown, water-soaked, and soft and collapses.
Cultural control
- Use Fusarium-free seed
- Crop rotation and burying residues reduce the amount of disease.
- Do not over-fertilize with nitrogen.
- Avoid root pruning when close-cultivating and injecting fertilizer.
- Use resistant varieties such as 'Champ' or 'Dugan'. Other resistant varieties may be available from your seed distributor.
Biological control
- Bexfond at 7 to 14 fl oz/A. O