Potential of Heterorhabditis zealandica (Rhabditida: Heterorhabditidae) for the control of codling moth, Cydia pomonella (Lepidoptera: Tortricidae) in semi-field trials under South African conditions

ABSTRACT

Infection of codling moth, Cydia pomonella (L.), larvae by the entomopathogenic nematode, Heterorhabditis zealandica, was studied under semi-field conditions. Late-instar diapausing codling moth larvae, coccooned in perforated cardboard strips, were used in all trials to evaluate the nematode treatments involved. A morning application of 0.5, 1.0 and 1.5 MM infective juveniles (IJs) per tree resulted in 85%, 95% and 100% codling moth larval infection, respectively. Contrasting results were obtained for an evening application, with low levels of codling moth infection (<50%). Nematode treatment strips placed in direct sunlight resulted in almost no infection (<10%), opposed to strips attaining 67% infection placed in the shade.

KEYWORDS:

• Codling moth
• Cydia pomonella
• entomopathogenic nematode
• semi-field trial
• South Africa
• Heterorhabditis zealandica

Acknowledgments

The authors would like to thank T Ferreira and NF Stokwe for their technical assistance, as well as D Nel for assistance with the statistical analysis.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors would like to thank the South African Apple and Pear Producers’ Association (SAAPPA) and the National Research Foundation of South Africa (NRF-THRIP) [grant number TP14062571871] for funding of the project.