gummy stem blight of watermelon

Gummy stem blight-One of the most common foliar diseases of watermelon in Indiana. Lesions on leaves are amorphous, dark and may appear water-soaked. Dark fungal bodies (pycnidia) may be observed in lesions on leaves or stems. I have never observed fruit infection of watermelon in Indiana. 

Figure 1. Gummy stem blight Figure 1. Gummy stem blight causes dark, amorphous, necrotic lesions on watermelon leaves.
Figure 2. Gummy stem blight lesions on watermelon leaves sometimes have a ring-like structure. Figure 2. Gummy stem blight lesions on watermelon leaves sometimes have a ring-like structure.
Figure 3. Underside of a watermelon leaf with a gummy stem blight lesion. Figure 3. Underside of a watermelon leaf with a gummy stem blight lesion.
Figure 4. Large gummy stem blight lesion along the midrib of a watermelon leaf Figure 4. Large gummy stem blight lesion along the midrib of a watermelon leaf
Figure 5. Close up of gummy stem blight lesions on a watermelon leaf, one lesion with a shot-hole. Figure 5. Close up of gummy stem blight lesions on a watermelon leaf, one lesion with a shot-hole.
Figure 6. Lesion of gummy stem blight on a watermelon leaf petiole. Figure 6. Lesion of gummy stem blight on a watermelon leaf petiole.
Figure 7. Lesion of gummy stem blight on a watermelon stem. Figure 7. Lesion of gummy stem blight on a watermelon stem. The brown ooze or gum does not always occur in association with this disease and many other diseases and injuries to the stem may cause such an ooze.
Figure 8. Fruiting bodies, pycnidia, on a watermelon leaf petiole. Figure 8. Fruiting bodies, pycnidia, on a watermelon leaf petiole.
Figure 9. A field of watermelon with a severe outbreak of gummy stem blight manifested by defoliation and numerous lesions. Figure 9. A field of watermelon with a severe outbreak of gummy stem blight manifested by defoliation and numerous lesions.