Occurrence of Phycopeltis Algae On Leaf and The Mitigation Measures: FRIM’s Experience

Phycopeltis is a genus of green algae belonging to the family Trentepohliaceae. It is well-known for its unique growth form and ecological niche, primarily as an epiphyte organism that grows harmlessly on the surface of another plant such as ornamental plants, fruit trees, and native forest species in the tropical regions, including Malaysia. It appears as green to orange spots on upper leaf surfaces, reducing photosynthesis and visual quality, though typically not causing major physiological stress. The algae outbreaks have increased, especially in humid, shaded urban areas such as FRIM, where colonisation reaches canopy heights. The diagnosis is based on colony colour, texture, and microscopic features such as dichotomous filaments. The algae do not invade host tissue but spread via wind, rain, and tools. Management includes pruning and spacing to reduce moisture, mechanical removal in mild cases, and copper-based fungicides for severe colonisation. Biological and irrigation-based approaches are supplemental. This article guides the identification and control of Phycopeltis algae while emphasising environmentally responsible management to minimise the risks of chemical treatments in sensitive urban landscapes.