SUMMARYThe potato cyst nematodes (PCN)Globodera pallidaandG. rostochiensisare major pests of potatoes. TheG. pallida(andG. rostochiensis) life cycle includes both diapause and quiescent stages. Nematodes in dormancy (diapause or quiescent) are adapted for long-term survival and are more resistant to nematicides. This study analysed the mechanisms underlying diapause and quiescence. The effects of several compounds (8Br-cGMP, oxotremorine and atropine) on the activation of hatching were studied. The measurements of some morphometric parameters in diapaused and quiescent eggs after exposure to PRD revealed differences in dorsal gland length, subventral gland length and dorsal gland nucleolus. In addition, the expression of 2 effectors (IVg9 and cellulase) was not induced in diapaused eggs in water or PRD, while expression was slightly induced in quiescent eggs. Finally, we performed a comparative study to identify orthologues ofC. elegansdiapause related genes in plant-parasitic nematodes (G. pallida, Meloidogyne incognita, M. haplaandBursaphelenchus xylophilus). This analysis suggested that it was not possible to identifyG. pallidaorthologues of the majority ofC. elegansgenes involved in the control of dauer formation. All these data suggest thatG. pallidamay use different mechanisms toC. elegansin regulating the survival stage.