Alternative to the Use of Probit 9 Mortality as a Criterion for Quarantine Treatments of Fruit Fly (Diptera: Tephritidae)-Infested Fruit

Current Trends in Quarantine Entomology

“…Therefore, reducing the severity of a quarantine treatment may improve the shelf life or marketability of the commodity. Landolt et al (79) pointed out that the probit 9 standard may be too stringent for commodities that are rarely infested or are poor hosts, and hence a less severe postharvest treatment might still provide quarantine security. The alternative treatment efficacy approach measures risk as the probability of a mating pair or reproductive individual surviving in a shipment.…”

Potential for Escape of Live Boll Weevils (Coleoptera: Curculionidae) into Cottonseed, Motes, and Cleaned Lint at the Cotton Gin

“…Proportions indicate experimentally determined 24-h survival potentials of free adult boll weevils from the point in the ginning process marked by the base of an arrow to the next stage or output product at the tip of the arrow. A percentage preceded by "Յ" represents the p u (95% upper conÞdence limit) calculated for an observed zero recovery of marked adults surviving 24 h. For green boll/rock trap, and minimum and enhanced seed cotton cleaning estimates, see Sappington et al (2004b); for trash fan estimates, see Sappington et al (2004c). than the probit 9 level (99.9968%) traditionally required for quarantine security (Landolt et al 1984, Hughes 2003. Given that not even any dead boll weevils were recovered intact from the precleaning experiments (Sappington et al 2004b), the true mortality rate is likely much greater than that calculated based on the p u value.…”

“…As Landolt et al (1984) pointed out, the effectiveness of a probit 9 mortality rate attributed to treatment of a commodity in preventing introduction of a pest depends on the initial infestation rate. In a survey of cotton modules from three boll weevil-infested regions of Texas over 2 yr, mean estimates of boll weevils packed alive into modules ranged from 341 to 7,219 (Sappington et al 2004a).…”

“…With an initial heavy infestation of 7,219 boll weevils per module, and a 2.002 ϫ 10 Ϫ6 rate of survival under the most lenient ginning and stringent statistical scenarios, the number of live boll weevils segregating into the cottonseed per module is calculated to be 0.0145, or one weevil per 69 heavily infested modules. Males are unimportant in the context of potential boll weevil reinfestations (Landolt et al 1984, Baker et al 1990, Hughes 2003. Assuming a 1:1 sex ratio, one would expect one female per 138 heavily-infested modules to escape alive into the cottonseed.…”

“…The specter of reinfestations and the associated high costs of reeradication create a strong motivation for regulating transport of harvested cotton and gin products out of infested zones (Barker et al 2001, Dickerson andHaney 2001). Thus, it is imperative to understand and quantify the potential for boll weevil escape from the cotton gin so that future regulatory decisions can target true hazards while minimizing costly and unnecessary precautionary measures (Landolt et al 1984). Sappington et al (2004a) concluded from Þeld studies that substantial numbers of boll weevils indeed can be picked up at harvest and packed alive into cotton modules and Mention of trade names or commercial products in this article is solely for the purpose of providing speciÞc information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.…”