The groundnut leaf spots (early leaf spot and late leaf spot) commonly called as
“Tikka” disease cause nearly complete defoliation and yield loss up to 50 per cent or more depending upon disease severity.
The leaf spot disease epidemics are affected by weather parameters such as hot and wet conditions.
Under field conditions, initial symptoms of late leaf spot were noticed at 45-50 days after sowing of groundnut crop.
The most prominent symptoms appeared on the foliage in the beginning and later lesions on stem also developed.
The characteristic brown coloured lesions first appeared on the lower leaves which were usually smaller and almost circular. Early and late leaf spots in peanut can be differentiated on bases of colour of spot and yellow halo.
In case of early leaf spot colour is reddish brown while in case of late leaf spot it is dark brown.
Yellow halo is conspicuous and spreading in early leaf spot but dull and limited to margins of spot in late leaf spot.
— Leaf spot infected diseased plant materials should be properly destroyed.
— Growing resistant genotypes and do seed treatment with a talc-based powder formulation of Pseudomonas fluorescens reduced the severity of late leaf spot.
— Spraying of Trichoderma viride (5 per cent) and Verticillium lecanii (5 per cent) can reduce the disease severity.
— Neem leaf extract (5 per cent), Mehandi (2 per cent), neeem oil (1per cent), neem kernel extract (3 per cent), can effectively contain the disease.
— Two sprays of Hexaconazole (0.2 per cent), Carbendazim (0.1 per cent) + Mancozeb (0.2 per cent) Tebuconazole (0.15 per cent) and Difenconazole (0.1 per cent) reduced leaf spot disease.
— Bavistin at 0.1 per cent, followed by 2 per cent neem leaf extract + 1.0 per cent K2O significantly reduced the severity of leaf spot disease.
(Dr. Utpal Dey ,Department of Plant Pathology, Vasantrao Naik Marathwada Krishi Vidyapeeth, Parbhani, Maharashtra. D. N. Dhutraj is Associate Dean & Principal, College of Agriculture, Badnapur, VNMKV, Parbhani, Maharashtra, email: email@example.com)