Fusarium Rot

• Surface rot caused by fusarium is most common in roots that have been injured mechanically, by pests or by cracking during growth. These lesions allow for an entry point for the fusarium fungus. In many cases, surface rot is the first stage in a disease that progresses into full root rot.
  
  

Surface Rot Symptoms

• Plants infected with fusarium surface rot will feature round lesions that are brown in color and firm to the touch. These dry lesions will cause shallow decay to the roots of the plant. The external lesions most commonly appear on broken rootlets. Surface root rot is most common on plants that have been harvested and stored for long periods of time. As this disease progresses, the root hardens, shrinks and becomes mummified. Surface rot is normally confined to the vascular area of the root.
  
  

Root Rot Symptoms

• Fusarium root rot and surface rot have similar symptoms. The main difference between surface rot and root rot is that root rot causes lesions that can be seen in areas other than the vascular part of the root. The lesions caused by root rot are brown in color and feature concentric rings. The tissue surrounding each lesion may appear orange or light brown in color. It is spongy and moist to the touch. Within the lesions, white fungus can often be seen. With root rot, the entire root in infected and eventually mummifies.
  
  

Fungal Persistence

• Fusarium fungus overwinters in the soil and is capable of contaminating an area for a number of years. Because of its persistence, this fungus can infect multiple years' growth, especially when the roots have been damaged by mechanical harvesting methods. In cases where the fungus has infected stored plants, the disease is capable of rapidly spreading to other stored plants.
  
  

Treatment

• The best method of control is to prevent root rot by taking care not to damage the roots or stems of the plant during harvest and care. After harvest, the roots should be cured to prevent long-lasting moist conditions. Using insecticides to control damage from nematodes and pests can also prevent this disease. If the soil has become contaminated, do not plant healthy crops in the soil because they too will become infected. All transplants taken from other areas should be cut above the soil line to prevent introducing the disease to new soils.