Anthracnose: Brown spots on leaves
Pathogen: Colletotrichum gloeosporioides
Symptoms
Leaves turn yellow and fall out. Symptoms appear on flowers also. Appears as small regular or irregular dull violet or black leaf spots with yellowish halos.
Disease development
Primary source of inoculums is infected leaves. Secondary source of inoculums is wind born conidia. The disease is severe during August-September when there is high humidity and the temperature between 20-27ºC.
Control
Carbendazim/ Difenconazole or Thiophanate methyl at 0.25ml/lit sprays at fort-nightly intervals have been found effective. Spraying of Difenconazole 25 EC at 1.0 ml/lit or Prochloraz 45 EC at 0.75ml/lit were effective against anthracnose disease. Spraying of systemic fungicides namely Hexaconazole @1ml/lit / Thiophanate methyl @ 1g/lit/ Carbendazim @ 1g/lit at 20 days interval is quite effective. Among the contact fungicides Chlorothalonil (2g/l) followed by Mancozeb (2g/l) were more efficacious.