Root-knot nematodes

Meloidogyne incognita are microscopic roundworms that feed on the roots of plants. Foliage symptoms from the affected root system include stunting, wilting, and leaf yellowing. Infested roots develop gall-like swellings. Adult stages of the nematode live inside these root swellings. These root galls prevent the normal water and nutrient uptake by roots. Nematode numbers are often higher in sandy soils under warm summer weather. Clean fields may be infested by run-off irrigation water from nearby contaminated fields and from movement of soil or infested plant material. Soils may be tested to estimate parasitic nematodes populations.

Before planting, infested cucumber fields are normally fumigated for nematode control. Several grasses that are non-hosts to the root-knot nematode such as oats, barley, wheat, and rhodes grass, may also be grown before cucumbers. However some grasses may attract undesirable cutworm populations into the field. Cultural controls to reduce nematode numbers include crop rotations, fallow, field flooding, and destruction of volunteer weedy hosts. No resistance is available to rootknot nematodes in the cucurbits.

   Other nematodes that infest cucumber are the sting nematode, Belonolaimus spp., the root lesion or meadow nematode, Pratylenchus spp., the stubby root nematode, Trichodorus spp., and the Pin nematode, Paratylenchus spp. Yield losses from these nematodes range from moderate to heavy. In many cases nematodes do not affect yields directly, but bacterial and fungal infections may occur in root lesions caused by nematodes.

   Stinkbugs

   Stinkbugs of size from 1/2 to 2/3 inch in length feed on plant sap and inject toxins on the plant while feeding. Heavy feeding may deplete the plant of resources and reduce yields or make it susceptible to disease attack.