Actinomycosis of plants

Actinomycosis of plants is a widespread soil-borne disease caused by bacteria of the genus Actinomyces. These organisms, which resemble fungi due to their mycelial growth, are responsible for significant economic losses in potato and root crop production. They are prevalent in various soil types and act primarily as opportunistic pathogens under specific environmental conditions.

The primary hosts for this infection include potatoes, sugar beets, carrots, and radishes. The bacteria survive in the soil debris and rhizosphere, entering plant tissues such as tubers and fleshy roots through lenticels, root hairs, or openings created by mechanical damage or soil-dwelling pests like wireworms.

Symptoms are typically characterized by the development of corky lesions, scabs, or deep pits on the surface of the plant organs. These symptoms negatively affect the commercial value of the crop and create entry points for secondary pathogens like bacteria and fungi, which lead to post-harvest decay and reduced shelf life.

The disease development is heavily influenced by soil pH, with alkaline or neutral soils (pH 6.5–8.0) being highly conducive to the growth of Actinomyces. Low soil moisture during the tuber initiation stage is another critical factor that significantly increases the incidence and severity of the disease in the field.

• Practicing crop rotation to avoid planting susceptible crops in highly infested fields.
• Managing soil pH by avoiding excessive liming and utilizing acidifying fertilizers.
• Planting certified disease-free seed tubers and resistant cultivars.
• Controlling soil pests that cause physical wounds on the crop surface.
• Improving soil water management to maintain consistent moisture during tuber development.