Field Identification
Soilborne vascular wilt: the host-specific formae speciales of F. oxysporum plug xylem, causing one-sided yellowing, wilting despite moist soil, and brown streaks in stems. Tomatoes, melons, bananas, and many ornamentals each have their own pathotype.
Wilting progresses from lower leaves upward; cut stems show brown vascular ring; roots may look fine early. Confirmed diagnosis often needs lab isolation since other wilts mimic symptoms.
How to Deal With It
Organic Control Methods
No spray cures infected plants—soil drenches with Trichoderma spp. or Bacillus-based biocontrol products may suppress spore loads when used preventively on clean ground.
Nonpathogenic Fusarium strains, mycorrhizae, and competitive Trichoderma in planting mixes can reduce infection incidence on transplants.
Use resistant cultivars where available; long rotations away from susceptible hosts; avoid moving field soil onto sterile mix; sanitize tools and stakes; improve drainage.
Soil solarization in hot climates; steaming propagation beds; destroy infected plants including root balls—do not compost.
Start with certified seed and clean transplants; test irrigation water; avoid ammoniacal nitrogen sources that some studies link to worse Fusarium on certain crops.
Let Nature Handle It
Natural Enemies
- Trichoderma harzianum
- Bacillus subtilis
- Nonpathogenic Fusarium
Threat Map