Persistence, horizontal movement, and efficacy of the Thai indigenous entomopathogenic nematode, Steinernema hermaphroditum EPNKU60 against larvae and pupae of stable fly, Stomoxys calcitrans L. (Diptera: Muscidae) under laboratory conditions

Abstract

The stable fly (Stomoxys calcitrans) is an important insect pest in livestock production because it is both a nuisance and a disease carrier. The use of chemical insecticides on farms is reduced via biological control of stable fly populations. The use of the entomopathogenic nematodes (EPN) has been successful in controlling many insects worldwide, especially those that live on the ground. The purpose of this study was to investigate the ability of the EPN, Steinernema hermaphroditum EPNKU60 against the stable fly under laboratory conditions. The death rate of the last instar of the greater wax worm (Galleria mellonella) employed as bait was used to determine the EPN's persistence and horizontal movement ability in cow manure. The EPN survived in cow manure at 1, 3, 5, and 7 days, with all treatments killing 100% of wax moth larvae within 72 hours of testing. The EPN approached the prey horizontally at distances of 0, 5, 10, and 15 cm, with all treatments resulting in a mortality rate of wax moth larvae ranging from 98-100% within 72 hours of testing. Furthermore, the second instar of stable fly was more susceptible to the EPN than the third instar, however the EPN did not infect the pupal stage. At 144 hours following testing, the EPN at rates of 12, 25, 50, and 100 IJs/cm² killed the second and third instars of stable fly larvae at 70-100% and 47-87%, respectively. In conclusion, S. hermaphroditum EPNKU60 may survive and hunt for prey in cow manure. It is also useful in controlling stable fly larvae.