Globodera pallida Pale potato cyst nematode Damage to potatoes.  Presence of the pale potato cyst nematode in potato growing areas preclude the export of potatoes to international markets due to the restrictions imposed by many countries against this pest.  Biology.   Juveniles penetrate host roots where they establish a feeding site, developing into cysts.  Females range in color from white to yellow, new cysts are glossy brown in color. Ecology.  Globodera pallida  has been found in Canada, as well as countries in South and Central America.  Nematodes are dispersed with soil debris and plant material contaminated by the cysts and by infected potato tubers.  Symptoms.   Under poor nematode management, crop losses induced by G. pallida range 20-70%.   Patches of poor growth may occur generally in the crop, sometimes with yellowing, wilting or death of foliage.  At extremely high nematode densities, tubers may become infected, resulting in the appearance of cysts on their surface.  Damage to other crops. Other Solanum species are hosts of G. pallida, including tomato. Control.  References-Links.  SON pest list information