Cause Fusarium oxysporum f. sp. asparagi, F. proliferatum, and F. redolens, fungi that persist in soil and can be seed-transmitted. High soil temperatures (optimum about 82°F) favor the disease, which is more severe on plants in light soils. Low soil pH, poor soil drainage, or low levels of available Mn in soil may all favor disease. A high soil K to Mg ratio, if it creates a Mg deficiency, is associated with disease. These soil factors may negatively impact plant growth, making plants more susceptible.
Symptoms Yellowing, stunting, and wilting of the stalk and ferns. Reddish lesions can develop on stalks bases. Rusty red discoloration of vascular bundles can be detected in roots, crowns, or stems. Fine roots rot away while storage roots eventually collapse from rot. Rot of the crown leads to plant death.
Cultural control
- Rotate with grasses and cereals.
- Plant only transplants grown from treated seed on clean ground.
- Avoid planting crowns too deeply in the ground,
- The cultivars UC72, UC500, and UC66 are moderately resistant in California but not in eastern Washington.
- NaCl fertilization has been reported to reduce root lesions by promoting changes in the rhizosphere (root-soil interface).
Chemical control
- Manzate 75 DF (Group M3) at 1 lb/100 gal water. Soak clean (free of soil), loosely packed crowns in a continuously agitated fungicide suspension for 5 min. Drain and plant immediately. Wash dirty crowns before dipping. 24-hr reentry.
- Ridomil Gold SL (Group 4) at 1 pint/A applied 30 to 60 days before the first cutting and again just before harvest. Apply after planting seedlings or after covering one-year-old crowns. Preharvest interval is 1 day. 48-hr reentry.
Biological control
- Actinovate AG at 3 to 12 oz/A as a soil drench at planting. 4-hr reentry. O
- Actinovate Lawn & Garden at 1/2 to 1 teaspoon/gal water. H O
- Double Nickel LC at 0.5 to 4.5 pints/A as a soil drench at planting. 4-hr reentry. O
- Prestop WG as a soil drench. 4-hr reentry. O
- Rootshield WP at 3 to 5 oz/100 gal water for field chemigation or at 16 to 32 oz/A as an in-furrow spray. 4-hr reentry. O
References Elmer, W.H. 2003. Local and systemic effects of NaCl on root compositions, rhizobacteria, and fusarium crown and root rot of asparagus. Phytopathology 93:186-192.
Hamel, C. et al. 2005 Factors associated with fusarium crown and root rot of asparagus outbreaks in Quebec. Phytopathology 95:867-873.