Unmanaged host trees of codling moths pose risks to apple industry

The New Zealand apple industry has achieved great success in controlling codling moths on orchards using biocontrol to meet the increasing demands for sustainable ultra-low residue fruit and strict phytosanitary requirements of over 60 export markets.

Since adult codling moths can fly several kilometres, depending on wind conditions and topography, on-orchard control alone would never eradicate the regional population. Researchers from Plant & Food Research and the University of Auckland set out to assess the uncontrolled populations of the pest in the peri-urban area of Hawke’s Bay, the heart of the New Zealand apple industry. Assessments were conducted in Hastings, a city of 70,000 people surrounded by commercial apple orchards, and Ongaonga, a small rural settlement near a pilot codling moth eradication zone. 

Using sex pheromone traps, the research team caught nearly 1,000 moths in one season in Hastings. The catches were heavily clustered around host trees such as backyard walnut and apple trees across different suburbs. Many host trees in Ongaonga surrounding the pilot eradication orchards also had populations of codling moths.

The findings highlight the external risks the industry continues to face and the importance of integrating town and country in pursuing area-wide suppression and reducing the risk of migration of codling moths from peri-urban host trees to commercial orchards. An expansion of the successful Sterile Insect Technique (SIT) programme could be one of the special measures on the cards.  

Journal ReferenceHorner, R.; Paterson, G.; Walker, J.T.; Perry, G.L.; Jaksons, R.; Suckling, D.M. Will Peri-Urban Cydia pomonella (Lepidoptera: Tortricidae) Challenge Local Eradication? Insects 2020, 11, 207. https://doi.org/10.3390/insects11040207