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SYMPTOMS

The symptoms described below are indicative of a nematode problem, but are not diagnostic because they could result from other causes as well. In general, aboveground symptoms include stunted, yellowed, chlorotic, and/or dead plants. Infected plants are likely to wilt earlier under temperature or moisture stress. Infestations may occur without causing any aboveground symptoms.

Feeding by root knot nematode causes characteristic swellings, called galls, on roots. Galls caused by Meloidogyne chitwoodi are small and difficult to see. On heavily infested plants, egg masses appear as tiny round bumps on feeder roots. Meloidogyne hapla causes small distinct galls with proliferation of lateral roots around these galls. Meloidogyne incognita causes more pronounced galls. All three species of Meloidogyne and Pratylenchus penetrans cause bumps or warts on the surface of infected tubers. However, those caused by M. hapla are less distinct. Brown spots develop inside tubers, mostly in the outer 0.25 inch (6 mm), which are visible when a thin layer of tuber is peeled off. Lesion nematodes cause reddish brown lesions on the roots that turn black later. Stubby root nematodes cause numerous short and stunted (stubby) roots, and corky ringspot symptoms on tubers.

Symptoms: Root-knot nematode infection rarely causes above-ground symptoms in potatoes. External symptoms of M. chitwoodi are distinct pimple-like bumps and lumps on tubers. M. hapla usually produces a more general swelling on the tuber or none at all. Both species produce brown spots within the vascular ring, within 0.25 inch of the tuber surface. Brown spots are about 0.04 inch (1 mm) in diameter and are evident only when the female nematode begins egg production. The female's white body and egg sac containing eggs (egg mass) produced outside the body often can be seen with a hand lens in the center of the brown spot. Unless several nematodes are in the same area, the spots' borders are distinct. The spots should not be confused with symptoms of heat necrosis, which produces spots of similar size but more diffused. Tubers infected with late season infection of M. chitwoodi may not show visible external or internal symptoms at harvest but may develop them in storage.

You are not the only one.
If you read down to "Help" some of us had the same problem this year and still not sure where the problem is. Maybe the seeds