Causal Agents: (fungi ‑ Rhizoctonia solani, Pythium spp.)
Seedlings wilt and die. The lower stems have a watersoaked appearance. Damping off is usually a problem of direct-seeded watermelons germinating in cool, moist soil (Image 1), but Pythium aphanidermatum can rapidly kill new transplants in warm soils (Image 2). A soil application of mefenoxam (Ridomil Gold) at the time of planting will prevent damping-off caused by Pythium species.