Submitted to: Journal of Entomological Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/27/2020
Publication Date: N/A
Interpretive Summary: Exports of sweet cherries from the United States can be impeded by some countries requiring a treatment of the fruit to prevent the accidental introduction of codling moth. Although codling moth is a serious pest of apples, its rare occurrence in sweet cherries, which are not a preferred host, is considered a threat to some importing countries. Historically, fumigation with methyl bromide, an ozone depleting substance, has been the preferred treatment. Researchers at the USDA-ARS laboratory in Wapato, WA with the assistance of scientists at the Battelle Northwest Laboratories in Richland, WA investigated the potential of irradiation to control the infesting stages of codling moth in sweet cherries. Irradiation provides a non-chemical, residue free method for controlling pests of quarantine concern. It was determined that the 3rd instar of codling moth was the most resistant to irradiation, requiring a dose of 250 Gy to prevent adult emergence. These findings support the stance that irradiation is a safe and effective method to meet quarantine restrictions, and is a viable alternative to fumigation.
Technical Abstract: Codling moth, Cydia pomonella (Lepidoptera: Tortricidae), is a serious pest of apple, pear, and occasionally, stone fruit. Its presence in sweet cherries is rare and presumed to occur in areas where high populations in pome fruits occur near sweet cherries. Nevertheless, the potential of codling moth residing in a sweet cherry destined for an export market, especially to Asian Pacific countries, has led to the continued use of methyl bromide, an ozone depleting fumigant, to prevent the accidental spread of this pest. Over the past 20 years internationally accepted alternative phytosanitary treatments using ionizing radiation have been developed. This is the first report of an irradiation dose response of codling moth in sweet cherries. We treated the first three instars of codling moth in export quality sweet cherries and found that the 3rd instar was the most radioresistant, requiring a dose of approximately 250 Gy to prevent adult emergence. This dose is higher than those reported for 5th instar codling moth in apples and artificial diet but should not delay any efforts in using this highly effective treatment to meet quarantine restrictions against this pest.