Abstract
The poor survival of EPNs storage is one of the main factors that prevent them from realizing their full potential as bioinsecticides. Of several EPNs isolates, two effective Heterorhabditis spp. isolates and/or strains (N169 and 195) were selected to study the storage stability of their infective juveniles (Us) and conducting bioassay test of the EPNs during storage period at room temperature (23 +/- 2 degrees C) (February-April). Survival rate of Us in control (water) was significantly lower compared with those stored in vermiculite or calcium alginate granules (gel granules) and significantly higher in calcium alginate granules than in vermiculite. Both isolates had higher survival rates in calcium alginate granules than in vermiculite. At room temperature, both storing methods of Us had no effect on the mortality rate of G. mellonella larvae during the first two weeks of storing period. However, both storing methods and isolates affected the Us during longer storing periods. Longer shelf-life could be improved in refrigerated containers than at room temperature. The results suggest that storing in calcium alginate granules was more suitable for storage of large quantities of nematode for commercial use in biological control programs.