A Watermelon Vine Turning Yellow

Identification

• Watermelon is susceptible to fusarium wilt, a serious disease caused by Fusarium oxysporum f.sp. niveum, also referred to as FON. The pathogen is strictly host specific and infects only watermelons. The fungus persists in soil for extended periods.

Damage

• The disease begins with wilting in only certain areas. The fungus clogs the vascular or water-conducting tissues in the vine. This leads to all the symptoms related to water deprivation including yellowing, wilting, browning and eventual death of the plant. Roots outwardly appear white and healthy, but cross-sectional inspection reveals discoloration.

Control

• This disease is hard to control; prevention is among the best management practices. Rotate crops to disperse fungal spores in soil and reduce symptoms. Fumigating soil before planting lessens the chances of infection. Obtain healthy transplants from reliable sources.