Leaf spot disease is caused by fungi that live in the soil and on crop residues. Before sowing, mix Trichoderma or Pseudomonas powder with compost and spread it on the field. Coat your seeds with Trichoderma or Pseudomonas powder. To reduce the spread of the disease by wind, grow a tall crop in between your groundnut crop. Ensure proper drainage. When your field is affected by leaf spot disease, spray the crop with a solution of Trichoderma or Pseudomonas. Or mix cow urine, sour butter milk and jaggery in water and use this solution to spray the entire crop.