Charcoal rotCaused by: Macrophomina phaseolina
Problem Category: Fungal Disease
Symptoms: Water soaked lesions on stems of seedlings close to soil line; lesions girdle stem and kill seedlings; lesions in similar area may be present in older plants; lesions are initially water-soaked but turn brown; if lesions girdle the stem, plant wilts and branches die; infections beginning in the roots cause leaves to turn yellow and wilt and causes stems to be blighted.
Comments: Fungus survives in crop debris in the soil; disease emergence is favored by high soil temperatures which cause plants to be water stressed and more susceptible to disease; fungus can survive for prolonged periods in dry soils but are killed in wet soil.
Management: Rotating crop with rice for a period of 3-4 years can reduce the level of oioculum in the soil; providing the plants with adequate irrigation and fertilization reduces susceptibility to the disease; there are currently no resistant varieties of peanut; frequent irrigation to wet soil reduces the incidence of the disease.
Control: spray 6 litres neem oil to control the charcoal rot