Reproductive potential and Host Searching Ability of Entomopathogenic nematode, Steinernema feltiae

Due to non-availability of mass production techniques in Pakistan, the development and application of entomopathogenic nematodes (EPN) depend on the use of host insects for in vivo production. As there is little information regarding relationship between nematode dosage and production of infective juveniles (IJ) of Steinernema feltiae and ability to locate hosts, therefore, in the present studies investigations were done on these aspects. A significantly greater emergence of IJ of S. feltiae from Galleria mellonella was observed with White traps than with modified Baermann trays. Maximum juveniles of S. feltiae emerged at 50 IJ dose followed by 100 IJ. The emergence of IJ decreased significantly at the dose of 200 IJ and then increased with 400 IJ dose. The minimum number of juveniles emerged at the dose of 200 IJ. The relationship between inoculation dose and emergence of IJ by using both methods was non-significant.Similarly, with an increase in inoculum dose and time, invasion of host was significantly increased. There was little invasion at the 800 IJ dose even after 4 days whereas with the commercial dose (8,000), nematodes did migrate to the larvae and caused some infection after 2, 3 and 4 days. Greatest invasion took place with the highest dose (80,000) with 8 IJ successfully finding and penetrating the larvae. A positive correlation was observed between dose and time and invasion of the host. It is concluded that application of EPN in cadavers may be appropriate in Pakistan because of the non-availability of industrially produced isolates.