Pathogen:
1) Cercospora personata
2) Cercospora arachidicola
Symptoms:
All the parts of the plant found above the ground are affected, but specially the lesions of the disease appear on the leaves.
In India, generally the symptoms due to "Cercospora personata" appear; the symptoms developed by Cercospora arachidicola are rarely seen.
The lesions on the leaves, developed by C. personata are rounded and 1-6 mm in diameter.
These spots are dark brown or black and found on both the surfaces of the leaf. Later yellow halo developed around the such dark spots.
The spots surrounded by the yellow haloes are restricted to the upper surface of the leaf.
The lesions developed by C. arachidicola are irregular and bigger in size. Each spot is rounded and 4-10 mm in diameter.
The yellow haloes develop around the leaf spots from the very beginning. The inconspicuous haloes are seen on the lower surface of the leaf.
Control Measures:
The disease can be controlled to some extent by sanitation and crop rotation.
The use of phosphatic and potassic manure and mixed cropping with arhar, also reduce the disease.
The spraying with Bordeaux mixture, Perenox and cupravit, has also been proved effective to some extent. Sulphur dusting is quite effective.
Use of Resistant varieties and sowing early maturing varieties has shown good results.