Abstract:The anhydrobiosis and 8 species of entomopathogenic nematodes from Gansu Province,including 5species of Steinernema (S.feltiae 0619HT,S.bicornutum 0631PG,S.kraussei 0657L,S.karii 0663YC and S.affine 0619M) and 3 species of Heterorhabditis (H .megidis 0627M,H .brevicaudis 0641TY and H .marelatu0639G),were used to study the impact of low humidity on the survival rate,pathogenicity and fertility of thenematodes.The results showed that Steinernema spp.still kept high survival rate under the conditions of 50.5% humidity and 25℃ for 7 and 9 hours,but it was lower for Heterorhabditis spp.After the low humiditystress treatment for 9 hours and recovery,the pathogenicity of infective juveniles (IJs) of 4 species from Steinernema(S.feltiae 0619HT,S.bicornutum 0631PG,S.kraussei 0657L,S.karii 0663YC) were 100%,and nosignificant difference with the control (P >0.05),and as for S.affine 0619M,it was 75% (P <0.05).The invasionrate of all 5 species was lower than control.And there was no significant difference in the fecundity of S.felitiae 0619HT and H .megidis 0627M after low humidity stress.The resistance of Steinernema to low humiditystress was stronger than that of Heterorhabditis,especially S.kraussei 0657L.Low humidity stress reducedthe infection rate of entomopathogenic nematodes,but no significant influence on their pathogenicity.Moreover,the low humidity stress had no significant effect on the fertility of S.felitiae 0619HT and H .megidis0627M.