Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/9/2012
Publication Date: 4/9/2012
Citation: Neven, L.G. 2012. Fate of codling moth (Lepidoptera: Tortricidae) in harvested apples held under short photoperiod. Journal of Economic Entomology. 105(2):297-303; DOI: http//dx.doi.org/10.1603/ED11242.
Interpretive Summary: Codling moth is an important pest of apples in the United States and is the subject of quarantine restrictions in apples exported to countries where this pest is not present. There is controversy over whether codling moth in apples exported from the U.S. to Taiwan can establish populations and spread. Scientists at the USDA-ARS Yakima Agricultural Research Laboratory conducted a three year study to determine the potential of codling moth in apples to complete development under short days and without sufficient low temperature exposure needed to break dormancy. They found that very few moths emerged from infested apples, and that based on the reported interceptions of codling moth in apples exported to Taiwan over 5 years, less than 0.005 codling moths a year would successfully complete development and emerge. Based on this study it was determined that the potential for establishment of a sustaining and spreading population of codling moth in apples exported to Taiwan is remote. This information may be used in future trade negotiations with any country importing U.S. produced apples where the climate would not support codling moth populations.
Technical Abstract: Codling moth, Cydia pomonella L., is a cosmopolitan pest of pome and stone fruits. It has been identified as a quarantine pest of concern in a number of countries where it is not known to occur, most of them in tropical or subtropical countries. Although considerable work has been done on the basic biology and physiology of this temperate pest, little is known on its potential to develop and establish in tropical environments with short photoperiods and few to no days below 10°C. Apples were harvested over 3 field seasons (2007 to 2009) from unmanaged orchards in central Washington State and subjected to simulated commercial cold storage at 1.1 ± 2°C for up to 119 d. Following cold storage, infested fruits were held at 20°C under a 12:12 L:D photoperiod for up to 6 months. Over the entire experiment only 27% of the larvae collected exited the fruit and cocooned. Of those 27%, only 1.06% of larvae held under a 12:12 L:D photoperiod successfully emerged as moths. No moths emerged when host fruit would be available in a representative importing country in the tropics over the 3 years of testing. These results indicate that codling moth in apples from the Pacific Northwest pose little threat of surviving and establishing in tropical regions where day length is insufficient to break diapause and the chilling requirement is not met.