Leaf spots (Cercospora spp.)
Symptoms of early leaf spot (Mycosphaerella arachidis, Cercospora arachidicola) consist of sub-circular dark brown spots produced on the upper leaflet surface. The spots are of lighter shade of brown on the lower side of the leaflets. Yellow halo is seen around the brown spots. Oval to elongate spots are also seen on stems, petioles, and pegs. Late leaf spot can be distinguished from those of early leaf spot.
Late leaf spots (M. berkeleyi, Cercosporidium personatum) are darker with no or light yellow halo. The late leaf spots on the lower leaflet surface are rough in appearance. They exhibit circular rings of fungus fruiting structures on the lower leaflet surface. Severe disease attack leads to shedding of leaflets resulting in premature ageing of the crop. Oval to elongate spots similar to early leaf spot are also formed on stems and pegs. Late leaf spot attack is usually seen along with rust disease.
- Plant tolerant / resistant varieties, if available.
- Collect and destroy the infected crop debris.
- Follow cereal-cereal- groundnut crop rotation.