Systems approach to quarantine security: postharvest application of sequential mortality in the Hawaiian grown 'Sharwil' avocado system
1996
Jang, E.B.
Natural mortality of eggs and larvae after 24 h in mature green avocado fruit and efficacy of a heat treatment (40 degrees C) applied to infested fruit were determined for 3 species of tephritid fruit flies. The estimated populations of each immature developmental stage in the fruit were calculated from estimates of the total numbers of eggs or larvae placed in the fruit or from actual numbers of insects that survived to pupae in untreated (control) fruit. Significant natural mortality was associated with the insects being present in the fruit without a postharvest heat treatment. A subsequent heat treatment (40 degrees C, 24 h) further reduced the estimated surviving population by 99.5-100%. A hypothetical population of 100,000 eggs or larvae was subjected to a sequential mortality model in which the likelihood of survival of the various immature stages in the fruit, as well as after a heat treatment was determined based on the above mortality estimates. Immatures that survived both the initial natural mortality within fruit and the heat treatment were once again subjected to further stage-specific mortality within fruits. Application of the sequential mortality concept to both Mediterranean fruit fly, Ceratitis capitata (Weidemann), and melon fly, Bactrocera cucurbitae (Coquillet), in the avocado system would be sufficient to meet probit 9 (99.9968% mortality) security using our model. Oriental fruit fly, Bactrocera dorsalis (Hendel), eggs and 3rd instars would not meet probit 9 quarantine security. The implications of this study to systems approaches to quarantine security and risk are discussed.
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