Plant Diagnosis

Red Rust of Tea Critical

Algal disease causing reddish-brown spots on tea leaves caused by Cephaleuros virescens (parasitic alga) in June-October (monsoon season).

Description

Red rust is a unique disease caused by a parasitic alga that affects tea plants during prolonged wet periods. The pathogen forms characteristic reddish-brown, circular spots on leaf surfaces with hair-like structures (sporangiophores) visible under magnification. The disease is most severe in shaded areas with poor air circulation and persistent moisture. While not immediately lethal, it reduces photosynthetic capacity and weakens plants.

Symptoms

• Reddish-brown spots, hair-like structures, leaf yellowing, leaf drop.