~ 241 ~ Journal of Entomology and Zoology Studies 2019; 7 (3): 241-244 E-ISSN: 2320-7078 P-ISSN: 2349-6800 JEZS 2019; 7 (3): 241-244 © 2019 JEZS Received: 04-03-2019 Accepted: 08-04-2019 Jisna George Department of Nematology, Assam Agricultural University, Jorhat, Assam, India Gitanjali Devi Department of Nematology, Assam Agricultural University, Jorhat, Assam, India Badal Bhattacharyya Department of Entomology, Assam Agricultural University, Jorhat, Assam, India Correspondence Jisna George Department of Nematology, Assam Agricultural University, Jorhat, Assam, India Survival and infectivity of entomopathogenic nematode Oscheius rugaoensis in different formulations against wax moth, Galleria mellonella Jisna George, Gitanjali Devi and Badal Bhattacharyya Abstract Entomopathogenic nematode, Oscheius rugaoensis were formulated in six different formulations such as talc, sawdust, alginate gel, water dispersible granule, compost: charcoal powder mixture and water. All formulations tested in vitro at two temperatures (5 0 C and 30 0 C) to evaluate their storage and infectivity against wax moth, Galleria mellonella. Sawdust and Alginate gel formulations were enhanced highest survival of infective juveniles of Oscheius rugaoensis than the other formulations. Per cent survival of Oscheius rugaoensis infective juveniles (IJs) was 98.30% in sawdust and 97.30% in alginate gel up to 6 th week of storage at 5 0 C, whereas per cent survival was less (95.50% and 93.76 % respectively) at 30 0 C up to 6 th week of storage. Larval mortality of G. mellonella by Oscheius rugaoensis was 47.66%, 67.33%, and 81.66% at 24 h, 48 h and 72 h respectively at 5 0 C whereas larval mortality was 43.66%, 64.66% and 78.00% at 24 h, 48 h and 72 h respectively at 30 0 C. Keywords: entomopathogenic nematodes, survival, infectivity, formulation, storage temperature 1. Introduction Entomopathogenic nematodes (EPNs), Steinernema, Heterorhabditis and Oscheius in the family Steinernematidae, Heterorhabditidae and Rhabditidae respectively of the order Rhabditida are obligate parasites of insect pests and distributed in natural and agricultural soils. EPNs are considered as one of the most significant non-chemical alternatives to insect pest control due to their high reproductive potential, ease of mass production and their harmlessness to animals, humans and plants. Nematode formulation is the most important aspect in the commercialization of nematode as a biocontrol agent. After mass production, entomopathogenic nematodes are formulated for ease of use, transport and field application. High oxygen and moisture requirement of nematodes, microbial contamination, sensitivity to temperature and behaviour of infective juveniles in order to maintain viability and storage stability, limit the choice of the formulation method and ingredients. The infective stage nematodes need to be formulated into solid or semi liquid substrates soon after they are mass cultured which guarantee survival for a period necessary to market the nematode product. Hence the present study was carried out to formulate Oscheius rugaoensis in different formulations and test their survival and efficacy against larvae of wax moth (Galleria mellonella). 2. Materials and Methods 2.1 Nematode culture Indigenous culture of Oscheius rugaoensis was maintained in the lab on G. mellonella larva. Infective juveniles were collected from infected cadavers by using white trap method [1] . 2.2 Formulations of Oscheius rugaoensis 2.2.1 Talc formulation Talc powder (250 g) was added to 25 ml of distilled water in a 500 ml beaker and mixed thoroughly. Fifty ml of freshly harvested IJs of Oscheius rugaoensis (2000 IJs/ ml) were added in the above moisten talc and then the contents were thoroughly mixed till the nematode suspension spread over evenly into the talc.