FOREST DISEASE MANAGEMENT

DISEASES OF Pongamia pinnata
            Pongamia is attacked by few diseases. A brief description of the nursery diseases is given below:

a) Leaf spot and blight:
Leaf spot and blight diseases caused by Fusicladium pongamiae on Pongamia pinnata. The pathogen causes severe leaf deformities.  Microstroma pongamiae causes white to cream-coloured spots giving a yellowish appearance to the leaves. Other fungi such as Phyllochora pongamiae, Robillarda makatii and Urohendersonia pongamiae cause leaf spot disease.
Cercospora pongamiae and Sphaceloma pongamiae cause anthracnose spots on leaves, tender shoots and pods resulting in severe damage and early defoliating in young seedlings and trees.

Control Measures:
Foliar spray of Bavistin fungicidal solution (0.1%) is found to be effective in minimizing the disease.

(b) Leaf Rust:
            The rust fungus, Ravenelia hobsoni infects the leaves and produces numerous chest-nut brown teliospore heads on the lower surface of the leaves. Another rust fungus, R. stictica is also known to attack the leaves. 

Control Measures:
Dusting or foliar spray of sulphur based fungicide (0.05%) is found to be effective in minimizing the disease.

(c) Powdery mildew:
            Powdery mildew disease caused by Oidium sp. was also reported on Pongamia seedlings.

Symptoms:
            The pathogen formed irregular white patches, consisting of mycelium and asexual conidia on the surface of the leaves.  These patches coalesced and covered the whole leaf lamina giving grayish white appearance.  Severely infected leaves and leaflets defoliated prematurely.

Control Measures:
Foliar spray of Bavistin fungicidal solution (0.01%) is found to be effective in minimizing the disease.