The most important disease reported to cause economic losses to the soyabean is anthracnose. Symptoms of the disease typically appear during early reproductive stages on stem, pods and petioles as irregularly shaped brown lesions.
Symptoms
Foliar symptoms include necrosis of leaf veins, leaf rolling, petiole canker and premature defoliation. Reddish brown spots appear on the pods and later turn black.
Anthracnosed plants are significantly shorter, with fewer pods and seeds with reduced seed weight compared to non affected plants. Infected seeds often show brown discoloration.
To prevent the infestation farmers are advised to go in varieties that are resistant to this disease.
Mehandi at 10 and 15 per cent was found least effective and caused minimum inhibition (40.36 per cent) of the test pathogen.
Garlic extract at 20 per cent concentration appeared to be best followed by onion, ginger and neem extracts.
Fungicides like thiophanate methyl followed by pyrimethanil and tabuconazole sprayed two times at the stage of flowering was found to give good results.
Instructions
In the field, Carbendazim at 0.1 per cent or Mancozeb at 0.1 per cent or four sprays of Dithane Z-78 (0.25 per ent) followed by Cupramer (0.25 per cent) and Ziram (0.25 per cent) significantly reduced the disease.
Seed treatment with Captan (0.2 per cent) and two sprays of Bavistin (0.1 per cent) at 15 days interval or seed treatment with MBC (0.15 per cent) and two sprays of MBC (0.1 per cent) at 15 days interval effectively controlled the disease.
Integrated field
Under integrated field condition, seed treatment with Carboxin, Tricoderma viride, neem leaf extract and Carbendazim as foliar spray significantly reduced the disease intensity and gave increased seed yield.
(Utpal Dey, scholar and G.P. Jagtap, Assistant Professor, Department of Plant Pathology, Marathwada Agricultural University, Parbhani, 431402, Maharashtra, India, email: utpaldey86@gmail.com, mob.ile 8275824103.)
