Potato cyst eelworms

Symptoms
Leaves turn yellow and then turn brown in the middle of summer. The brown discoloration gradually spreads up the stem causing early die-back. Potatoes produce a crop of small tubers when early dieback has occurred.

Spot them
Spherical objects, or cysts, up to 1mm in diameter can be seen on the roots if the plants are carefully dug up. These may be white, yellow or brown in colour, and are the swollen bodies of the female eelworms. Each one contains up to 600 eggs that can remain viable in the soil for many years.