Diseases of Fruit Plantation Medicinal and Aromatic Crops

Leaf spot

Causal organism: Colletotrichum gloeosporioides

Symptoms

• The disease appears as small, regular to irregular, dull violet or black spots on the leaves.
• These spots are surrounded by yellow margins.
• The infected leaves turn yellow and defoliate.

Epidemiology

• The disease is in severe form during August to November months when there is high humidity and the temperature between 20 and 27°C
• Mode of survival and Spread
• The pathogen survives in infected plant parts as dormant mycelia
• It spreads through airborne conidia produced in acervullus.
• Mode of entry is through stomata
Management

• Clean cultivation.
• Spray nitrogen solution (urea %) or bleaching powder to enhance degradation of fallen leaves or infected plant parts .
• Prune and burn infected branches and pruned material. The pruned area should be smeared with Bordeaux paste or COC paste.
• Spray thiophanate methyl (0.1% )or mancozeb (0.25%) or carbendazim (0.1%) on the plants.