Crown and spear rot

Phytophthora spp., Phytophthora megasperma

Symptoms:

  • Crown Rot: The crown, which is the base of the asparagus plant where the roots and stems meet, can show symptoms of rotting. This can manifest as discoloration, decay, or a softening of the tissue.

  • Spear Rot: The emerging spears, which are the edible shoots of asparagus, can also be affected. Infected spears may display discoloration, wilting, and rotting.

2. Causal Agent:

  • Fusarium oxysporum: This soilborne fungus is a common pathogen causing crown and root rot in various plants, including asparagus.

3. Disease Cycle:

  • Soil-Borne: Fusarium oxysporum can survive in the soil for an extended period, making it a persistent threat to asparagus crops.

  • Infection: The fungus infects the plant through wounds or natural openings. Once inside the plant, it causes decay and disrupts the vascular system.

  • Spread: The pathogen can spread through contaminated soil, water, and infected plant material.

4. Management:

  • Resistant Varieties: Planting asparagus varieties that are resistant or tolerant to Fusarium crown and root rot can help manage the disease.

  • Crop Rotation: Practicing crop rotation with non-host crops can help reduce the buildup of pathogen inoculum in the soil.

  • Sanitation: Removing and destroying infected plant material, especially crowns and spears, can help reduce the source of inoculum.

  • Soil Treatment: Soil fumigation or treatment with fungicides may be considered, especially in high-risk areas or when planting in known infested soils.

  • Proper Irrigation: Avoid overwatering, as excessively wet conditions can create a favorable environment for the pathogen.

5. Importance:

  • Fusarium crown and root rot can significantly impact asparagus yields and quality. The disease may lead to the decline of established asparagus beds and reduce the productivity of the crop.