Plant parasitic nematodes feed on plants by puncturing cells and sucking their contents with a needlelike mouthpart called a stylet. They have a wide host range, vary in their environmental requirements, and in the symptoms they cause. All cucurbits are susceptible to root knot nematodes.
Damage is typically greatest in warm regions with light, sandy soils.
Nematode-infested plants may have reduced growth, lower yield and fruit quality, and tend to wilt earlier under moisture stress. Lesion nematodes have not been found to cause economic damage in California, but the root lesions formed by their feeding may be invaded by fungi and bacteria. Stubby root nematode can reduce root growth. Pin nematode, Paratylenchus sp., is found in fields but is not known to cause damage to cucurbits in California . Needle nematode has been found to cause damage to cucurbits in the Imperial Valley.