desiccation tolerance among different isolates of the entomopathogenic nematode steinernema feltiae fillipjev poor storage capacity is a major constraint limiting further expansion of the use of entomopathogenic nematodes in order to prolong shelf life a quiescent state of the dauer juveniles djs should be induced this can be attained by means of desiccation of djs in this study 24 natural isolations of steinernema feltiae were exposed to desiccation stress in nonionic polyethylene glycol 600 the dehydrating conditions were measured as water activity awvalue nonadapted and adapted djs were tested separately under a series of dehydrating conditions the mean tolerated awvalue mw50 ranged from 085 for the isolate nep1 to 095 for fin1 isr5 and ita2 when not adapted to desiccation stress and from mw50 of 0822 for cr1 to 098 for isr6 when adapted to the stress conditions cr1 tolerated the lowest desiccation stress at an awvalue for the most tolerant 10 of the population mw10 at 065 when djs had been adapted to stress no significant differences were recorded between all isolates in nonadapted djs populations mw10 was compared no correlation between tolerance under nonadapted and adapted conditions were found most tolerant isolates will now be used for crossbreeding and subsequent genetic selection to enhance desiccation tolerance