Bioprospecting of agriculture and natural ecosystems for entomopathogenic nematodes

The aim of this study was to determine the occurrence and the distribution, of endemic entomopathogenic nematodes (EPNs) in South Africa. The objectives that are aimed at in this study include finding new, low-temperature-adapted EPN isolates to be used against key pests (specifically codling moth), during the cooler seasons. EPNs were isolated from the different soil samples, using live insects, such as codling moth, wax moth and mealworm, for trapping. The different nematode isolates found during trapping were identified using morphological, scanning electron microscopy, cross breeding and molecular techniques. New species found during the survey were described in full, as new species descriptions from South Africa and include S. sacchari, S. fabii, S. jeffreyense, S. nguyeni, S. litchii and Steinernema n. sp. (not named yet). The most abundant species being found were Heterorhabditis bacteriophora and Steinernema khoisanae  in the Western Cape with a high frequenc. Three H. zealandica isolates were identified associated with three different symbiotically associated bacteria on account of the colour change in wax moth larvae, which turned either steel grey, red and greenish. Commercially available species, such as S. feltiae, S. carpocapsae, and H. megidis have not yet been isolated from any of our soils. All nematode species has been maintained by recycling every three months to keep them alive. These new species has been used in different projects and tested for pathogenicity and low temperature activity. It was found that all South African EPN species isolated thus far are high temperature adapted nematodes, which make storage of them in a formulation at room temperature a viable option.