Submitted to: Entomology International Congress Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 9/2/1996
Publication Date: N/A
Technical Abstract: Several approaches to determining the risk of pest introduction have been proposed based on rates of infestation of commercial commodities. Rare infestation of the commodities because of non- host status or low pest populations may justify eliminating the requirement for postharvest quarantine treatments or reducing the severity of treatments. The "probit 9" (99.9968% mortality) was proposed in 1939 by USDA entomologists based on treatments for fruit flies. The probit 9 requirement has a questionable mathematical basis and frequently is not obtainable without unacceptable damage to many commodities. Recently techniques to calculate the conditions required to ensure a given level of security so as not to exceed a maximum pest limit, have been proposed. We examined the risk of pest introduction for the Mexican fruit fly Anastrepha ludens Loew for a series of host fruits and fruit production regions of Mexico. Proportions of fruit infested and numbers of insects per infested fruit were recorded for commercially important citrus and mango and for native hosts. Then the required treatment efficacy was calculated to allow less than a mating pair of Mexican fruit flies per commercial shipment. Calculations indicate that the currently required treatment efficacy provides security against introduction of a reproductive pair of flies only in fruit production areas that are managed to control fruit flies. The current management systems do not, in general, warrant reduction in treatment efficacy requirements.