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United States Department of Agriculture

Agricultural Research Service

Research Project: POSTHARVEST TREATMENT OF TROPICAL COMMODITIES FOR QUARANTINE SECURITY, QUALITY MAINTENANCE, AND VALUE ENHANCEMENT Title: Confidence Limits and Sample Size for Determining Nonhost Status of Fruits and Vegetables to Tephritid Fruit Flies as a Quarantine Measure

Authors
item Follett, Peter
item Hennessey, Michael - USDA-APHIS-CPHST

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 6, 2006
Publication Date: April 23, 2007
Citation: Follett, P.A., Hennessey, M.K. 2007. Confidence Limits and Sample Size for Determining Nonhost Status of Fruits and Vegetables to Tephritid Fruit Flies as a Quarantine Measure. Journal of Economic Entomology. Vol. 100, No. 2, pp.251-257

Interpretive Summary: Nonhost status is a quarantine measure that can be applied to exported commodities to ensure exported commodities are not infested with regulated pests. In the past, the number of insects or fruit tested to determine nonhost status has been far lower than the standard level expected for typical quarantine treatments (fumigation, heat, irradiation, etc.). For tephritid fruit flies, countries typically require that either 30,000 or 93,613 insects be treated experimentally with a quarantine treatment with no survivors to achieve 99.99 or 99.9968% mortality, respectively, at the 95% confidence level to meet quarantine security. This report outlines how the level of confidence in nonhost status can be quantified so that its equivalency to traditional quarantine treatments may be demonstrated.

Technical Abstract: Quarantine measures and treatments are applied to exported commodities to control regulatory pests and prevent their introduction into new areas. Nonhost status can be an effective measure used to achieve quarantine security. If it is determined that the regulatory pest will not be introduced with the fruit into the import area, then the nonhost approach can stand alone. The numbers of insects tested during investigation of nonhost status will determine the level of statistical confidence. If the level of confidence of nonhost status is not very high, then it can be part of a systems approach. Certain countries require that either 30,000 or 93,613 tephritid fruit flies be treated experimentally with a quarantine treatment with no survivors to achieve 99.99 or 99.9968% mortality, respectively, at the 95% confidence level to meet quarantine security. This report outlines how the level of confidence in nonhost status can be quantified so that its equivalency to traditional quarantine treatments may be demonstrated.

Last Modified: 12/19/2014
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