Potato cyst nematode
The potato root nematode or potato cyst nematode (PCN) is a 1-mm long roundworm that lives on the roots of plants of the Solanaceae family, such as potatoes. It causes deformed tubers and wilting of the above-ground plant parts, thus reducing the crop yield. The symptoms typically appear in patches on the farmland. There are two species: Globodera rostochiensis and Globodera pallida.
The eggs hatch in the presence of a substance (Solanoeclepine A) secreted by susceptible plants. The larvae then invade the plant roots and feed on them, thus inhibiting sap flow. The female individuals swell up and appear as cysts on the surface of the roots, each containing up to 400 eggs. The eggs can survive for up to 20 years inside these cysts.
Spread of the nematodes can be limited by cleaning equipment of possibly infested soil and using only certified PCN-free seed tubers. Pesticides can be used, but they do not act on dormant eggs. Crop rotation with at least 6 years between planting a susceptible crop is an effective means to limit the growth of the nematode population. The official recommendations and requirements for crop rotation vary between countries. Some potato varieties are less susceptible to PCN.
- PCN description by the Australian government
- UK Government technical overview
- Pictures of the nematodes and infected plants