Pink disease fungus

Erythricium salmonicola is a destructive fungal pathogen belonging to the kingdom Fungi and the genus Erythricium. It is primarily recognized as the causative agent of Pink disease, a condition that severely affects the bark of various perennial woody crops, leading to significant economic losses in tropical and subtropical agriculture.

The host range of Erythricium salmonicola includes economically important species such as Hevea brasiliensis (rubber tree), citrus varieties, tea bushes, and coffee trees. The disease is characterized by the formation of a conspicuous pink or salmon-colored mycelial crust on the bark surface. As the fungus invades the underlying tissues, it disrupts the vascular system, leading to bark cracking, dieback of branches, and sometimes complete plant mortality.

The biological cycle of the fungus is strictly governed by environmental conditions, particularly high relative humidity and moderate temperatures. The pathogen produces basidiospores that are disseminated by wind and splashing rain. Upon reaching a suitable host, the spores germinate and enter the plant through wounds, natural cracks in the bark, or pruning scars, initiating the infection process and mycelial growth within the cortex.

The spread of the disease is most rapid during the rainy season when persistent moisture keeps the bark surfaces wet, providing an ideal substrate for the fungus. Crowded plantations with poor canopy aeration create microclimates that favor the accumulation and spread of inoculum, turning minor outbreaks into widespread epidemics.

Effective management and control strategies include the following:

• Systematic monitoring to identify early signs of the pink mycelial crust.
• Aggressive pruning of infected branches, ensuring cuts are made well below the site of the lesion.
• Application of copper-based fungicides to protect healthy bark and treat pruning wounds.
• Implementation of proper agricultural practices, such as increasing canopy light and air circulation, to minimize moisture retention on the bark.