Traits of the entomopathogenic nematode, Heterorhabditis bacteriophora (Hb-EG strain), for potential biocontrol in strawberry fields

Abstract

AbstractEntomopathogenic nematodes (EPNs) can provide a substantial control, especially of the root feeding larval pests. The objective of the present study was to examine beneficial traits of an indigenous entomopathogenic nematode species, Heterorhabditis bacteriophora Poinar (Hb-EG strain), and to identify superior biocontrol candidates for suppression of the scarab beetle Temnorhynchus baal (Reiche & Saulcy) (Coleoptera: Scarabaeidae: Dynastinae) larvae as serious pests of strawberry in Egypt. The nematodes were applied to infect the greater wax moth, Galleria mellonella L. cadavers, to represent natural emergence from the host in laboratory and under field conditions. Its average yield was 49604 infective juveniles (IJs) per G. mellonella larva. Overall averages of nematode-induced mortality in G. mellonella larvae were (4.63, 3.12, and 1.92) at 4, 8, and 12 weeks, respectively, after continuous weekly baiting with 5 cadavers. Nematode capability for infection and reproduction ranged from 72 to 26% one to five months, respectively, after field inoculation of the infected larvae into the strawberry rhizosphere. The number of IJs, moved to the North of the rhizosphere, was significantly (P ≤ 0.05) less than that moved to the South or the East as reflected by the numbers of infected insects. The factors that may have a marked influence on EPN foraging behavior, persistence, and movement direction with implications for harnessing them as biological pest control agents were discussed.