Pink disease

Pink disease is a destructive fungal infection caused by the pathogen Corticium salmonicolor. It primarily affects the bark and cambium layer of woody plants. As an opportunistic fungus, it thrives in warm and humid environments, leading to significant economic losses in fruit orchards and forestry sectors worldwide.

The host range for this pathogen is broad, including economically important crops such as rubber trees, coffee, cocoa, citrus, and various fruit trees like apple and pear. The disease is particularly noted for its ability to girdle stems and branches, which effectively cuts off the nutrient transport system of the plant.

Symptoms typically manifest as a distinct pink or salmon-colored powdery fungal growth on the bark surface. As the infection deepens, the bark begins to crack, and small pustules form. Advanced stages are characterized by severe bark dieback, wilting of foliage distal to the infection, and eventually, the mortality of the affected branch or stem.

The spread of Corticium salmonicolor is highly dependent on environmental conditions, particularly moisture. Rainfall and high humidity facilitate the dispersal of fungal spores via water droplets, while wind carries the spores to new host plants. In orchards, poor spacing and lack of pruning promote microclimates that are highly conducive to the pathogen's proliferation.

Management strategies focus on eradication and prevention. Infected branches should be pruned at least 30-50 cm below the visible point of infection and removed from the site. Protective applications of copper-based fungicides are standard for treating exposed wood and preventing new infections. Improving orchard hygiene and maintaining balanced tree nutrition remain the best long-term defenses against this disease.