The wilting and rotting in watermelon may occur due to following pathogens
1. ￼Black root rot of watermelon caused by Thielaviopsis basico
2. Crown and foot rot of watermelon caused by Fusarium solani
3. ￼Fusarium wilt of watermelon caused by Fusarium oxysporum f.sp niveum
It is very important to know the causal organism to recommend any control measures. To diagnose further please provide the following information,
a. Symptoms on leaves other than wilting
b. Is wilting one sided?
c. Is there any discoloration in vascular tissue? (Hard to see from your image)
d. Percent of field infected?
e. Recent agronomic practice carried.
f. Weather conditions etc.
Black root rot of watermelon
Crown and root rot of watermelon
Fusarium wilt of watermelon
Posted by: Dr. Ravishankar Narayana
Posted: April 8, 2016