1)Powdery Mildew: Patchy, white powdery growth appears on upper surface of leaves and also on main stem of infected plant. It parasitizes the plant using it as a food source. In severe infestation it causes defoliation and premature fruit ripening.
If infestation is observed take spray of water soluble Sulphur@20gm/10Ltr of water 2-3times with interval of 10days.
2)Sudden wilt: It can affect crop at any stage. Plant get weak and give yellow appearance at initial stage, in severe infestation complete wilting is observed.
Avoid waterlogging in field. Destroy infected parts away from field. Apply Trichoderma Viride@1kg/acre mixed with 50kg FYM or well decomposed cowdung. If infestation is observed, take spray of Mancozeb or Copper Oxychloride@2.5gm/liter or Carbendazim or Thiophanate-methyl@1gm/liter of water.
3)Anthracnose: Anthracnose affected foliage appears scorched appearance.
As a preventive measure, treat seed with Carbendazim@2gm/kg of seed. If infestation is observed in field, take spray of Mancozeb@2gm or Carbendazim@0.5gm/liter of water.
4)Downy Mildew: It occurs frequently in muskmelon and less in case of watermelon. Yellowing occurs on upper side of leaves. Later yellowing get increases and center of leaves turning brown. Underside of leaves white-gray light blue fungus appears. Cloudy, rainy and humid conditions are favorable for spread of this disease.
If infestation is observed in field, take spray of Metalaxyl 8%+Mancozeb 64% WP (Ridomil)@2gm/Ltr of water.