Influence of Temperatures on Storage of Formulated Entomopathogenic Nematodes

Due to entomopathogenic nematodes EPNs represent excellent biological control agents for soil stages of several insect pests.  This work aimed to study the influence of the different temperatures on the survival and vitality of EPN IJs after a long-term duration, and evaluate the suitability of   EPNs, for formulation and storage on Hydrogel was used as a carrier medium. The new method was used for storage of IJs that was pieced in a square shape of Baby diapers which containing of Hydrogel (SAP), and fine cotton fibers to offer the moisture for IJs.  Four EPNs were investigated, three of them were foreign, Steinernema carpocapsae (S.c.), Steinernema glaseri (S. g.), Heterorhabditis bacteriophora (H.b.), and one indigenous, Heterorhabditis indica (RM1).  The tested EPNs divided into two main groups, the first group was stored at room temperature for 4 months, and the second was stored in the refrigerator for a long-term period extended up to 12 months. The survival and pathogenicity of the formulated EPNs were discussed. Results of the EPNs, which were stored at room temperature (group 1), showed that survival % of (RM1) and (S. g.) IJs were more than the others two (S. c.) and (H. b.). Also, (RM1) and (S. g.) achieved high pathogenicity % of the tested wax moth larvae, Galleria mellonella, morethan (S. c.) and (H. b.). The data showed excellent success in case of storage of EPNs IJs at low temperature (group 2), where all EPNs remained survive with percentage 100% for 5 months, while the survival of (S. g.) was 100% after 10 months, followed by (RM1) with survival 100% after 8 months, and (S. c.) as a long-term for 7 months. All EPNs species showed high vitality and infected the G. mellonella larvae with pathogenicity % reached to 85 %, 78%, 76%, and 72% by (S. g.), (S. g.), (S. c.), and (H. b.), respectively as storage long-term period expanded to 12 months.