Biocontrol introduction
Target pest: Oemona hirta (Coleoptera: Cerambycidae), lemon tree borer
Agent introduced: Heterorhabditis zealandica (Rhabditida: Heterorhabditidae) = Heterorhabditis heliothidis
Import notes:
Cameron et al. (1989) - no species have been imported for the biocontrol of O. hirta (an endemic New Zealand species). The biocontrol potential of three species of parasitic nematodes already present in New Zealand has been investigated, although not implemented in the field [see Cameron et al. (1989) entry in ‘Impacts on target’ section below]. The three species chosen were Steinernema bibionis, S. feltiae and Heterorhabditis heliothidis [though note that S. bibionis is now considered a junior subjective synonym of S. feltiae and H. heliothidis renamed H. zealandica (Nemys, accessed 5 April 2025) - see Taxonomic note (5 April 2025) entry in ‘General comments’ section below].
Impacts on target:
Cameron et al. (1989) - in trials, spray inoculation of nematodes (S. feltiae and H. zealandica) reduced O. hirta numbers, but it is doubtful that benefits would outweigh costs, and nematode applications do not appear to be economically useful control measures.
General comments:
Taxonomic note (5 April 2025) - Wouts (1979) described New Zealand populations of a Heterorhabditis species and concluded that they could be considered identical to H. heliothidis as described by Khan et al. in 1976. However, Poinar (1990) concluded that morphological evidence indicated the New Zealand populations were a separate species, which he described as H. zealandica. The status of Heterorhabditis heliothidis sensu Wouts is considered ‘unaccepted’ by Nemys (accessed 5 April 2025) and synonymous with H. zealandica (and the status of Heterorhabditis heliothidis sensu Khan et al. considered ‘uncertain’).
References
Cameron PJ, Hill RL, Bain J, Thomas WP (1989). A Review of Biological Control of Invertebrate Pests and Weeds in New Zealand 1874-1987. Technical Communication No 10. CAB International Institute of Biological Control. DSIR Entomology Division. 424p.
Nemys (). World Database of Nematodes. Bezerra TN, Vanreusel A (chief taxonomic editors), Ghent University https://nemys.ugent.be/
Poinar Jr GO (1990). Taxonomy and biology of Steinernematidae and Heterorhabditidae. In: Gauglar, R. and Kaya, H.K., Eds., Entomopathogenic Nematodes in Biological Control, CRC Press, Boca Raton, 23-61
Wouts W (1979). The Biology and Life Cycle of a New Zealand Population of Heterorhabditis heliothidis (Heterorhabditidae). Nematologica. 25(2): 191-202 https://doi.org/10.1163/187529279x00226
