March 2015. A few plants in the field of watermelons in Gujarat State, India, are said to have the symptoms in the photos. The climatic conditions were said to be warm during the day and cool at night, a variation of about 10-12 degree Celisus.
Members said that it was very difficult to respond to the enquiry without additional information and photos. Has the crop received any drift from herbicides or is there any possible contamination from herbicide residues left behind inside a tank used to apply pesticide to this or another crop.
Viruses, fungi, herbicides and a few other problems could produce these sort of symptoms hence the need for additional information. also, there is a need to see other plants, and to know how the crop is grown, especially if herbicide has been used.
The symptoms are different from gummy stem blight, although anthracnose is a remote possibility, but the collapse of that leaf on the right does not look right.