Red crown rot

Red crown rot is a destructive soil-borne fungal disease caused by the pathogen Phacidiopycnis (also known as Calonectria ilicicola). This pathogen specifically targets the roots and crown area of host plants, leading to a breakdown of the vascular system and preventing the transport of water and nutrients.

The disease primarily impacts soybean fields and hop gardens. It is considered a major threat in regions with persistent moisture and specific crop rotation patterns that favor the buildup of fungal inoculum in the soil. The pathogen persists in plant debris and soil for several years, making it difficult to eradicate completely.

Key symptoms of red crown rot involve the appearance of reddish-brown lesions on the crown and lower stem. When an infected plant is split open, the interior tissues often show a distinctive dark red or burgundy discoloration. Infected plants exhibit chlorosis, stunted growth, premature wilting, and eventually die before reaching physiological maturity.

Development and spread of the fungus are highly dependent on environmental factors, particularly soil moisture and temperature. Heavy rains and saturated soil conditions during the early growth stages of the crop facilitate the infection process. The fungus spreads via water runoff, movement of infested soil by agricultural machinery, and the use of infected planting material.

Managing red crown rot is challenging and requires an integrated approach. Effective strategies include:

• Utilizing resistant or tolerant crop varieties.
• Implementing long-term crop rotation to reduce soil inoculum levels.
• Ensuring proper field drainage to prevent water stagnation.
• Treating seeds with appropriate fungicides to protect early seedling growth.
• Maintaining rigorous sanitation protocols for machinery moving between fields.