SURVIVAL MECHANISMS OF ENTOMOPATHOGENIC NEMATODES

Entomopathogenic nematodes (Steinernematidae and Heterorhabditidae) ar e isolated from a wide variety of ecosystems ranging from sub-Arctic t o arid and tropical climates. It is expected that natural populations of these nematodes will be pre-adapted to specific ecological conditio ns in their environments. However, little is known about the survival strategies of entomopathogenic nematodes. This review focuses on the m ain survival mechanisms involved in the long-term persistence of nemat odes: extreme temperature tolerance (cold and heat), desiccation toler ance, osmotic tolerance, pesticide resistance and limitations of aerat ion. Physiological and biochemical mechanisms for survival are discuss ed. The review addresses the implications of the survival strategies o n the establishment of exotic and indigenous steinernematids and heter orhabditids.