Testing against umbrella or tree orderings for binomial proportions with an adaptation of an insect resistance case

Franco-Pereira, Alba M.; Nakas, Christos T.; Athanassiou, Christos G.; Pardo, M. C.

doi:10.1002/bimj.201900272

Cited by 1 publication

(3 citation statements)

References 29 publications

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“…This spot is located at a rather stable exposure, that of 5 h, and a rather stable concentration, that of www.nature.com/scientificreports/ 1000 ppm, or in some cases, 2000 ppm. This stands in accordance with the initial data provided by Franco-Pereira et al 48 for the umbrella peak of a phosphine resistant T. castaneum population. The fact that many populations, both susceptible and resistant, exhibited similar sweet spots, may suggest that this phenomenon is correlated with the mode of action of phosphine and insects' response, rather than a clearly hormetic pattern.…”

Section: Discussionsupporting

confidence: 93%

“…While the delayed effects and the immobilization-recovery patterns can be used to differentiate susceptible from resistant populations, in terms of different expressions in resistant populations, the sweet spot is rather a "global" phenomenon, as it is expressed almost equally vigorously regardless of the resistance level of the specific population that is examined. This is particularly important in the case of the use of phosphine in general, as short exposures trigger "umbrella/ inverse umbrella peaks", which can be attributed to self-regulated process [46][47][48] . In a recent study, Franco-Pereira et al 48 have modelled the "umbrella peak" phenomenon of adults of a single phosphine resistant T. castaneum population, under the context of binary dose-response variables.…”

Section: Discussionmentioning

confidence: 99%

“…This is particularly important in the case of the use of phosphine in general, as short exposures trigger "umbrella/ inverse umbrella peaks", which can be attributed to self-regulated process [46][47][48] . In a recent study, Franco-Pereira et al 48 have modelled the "umbrella peak" phenomenon of adults of a single phosphine resistant T. castaneum population, under the context of binary dose-response variables. In fact, this binary, i.e.…”

Section: Discussionmentioning

confidence: 99%

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Delayed mortality, resistance and the sweet spot, as the good, the bad and the ugly in phosphine use

Lampiri

Agrafioti

Athanassiou

2021

Sci Rep

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Phosphine is the most commonly used gas for fumigation for durable commodities globally, but there is still inadequate information regarding its efficacy in conjunction with proper concentration monitoring. In a series of bioassays, insect mortality after specific exposure intervals to phosphine in selected species was examined, as well as the appearance of the so called "sweet spot". The species that were tested were: Oryzaephilus surinamensis (L.), Tribolium castaneum (Herbst), Sitophilus oryzae (L.) and Rhyzopertha dominica (F.) with populations that had different levels of phosphine resistance. Evaluation was conducted by using the Phosphine Tolerance Test (PTT), with exposure of the adult stage for 15, 30, 60, 90, 150 and 300 min at 3000 ppm. At the end of these intervals (separate bioassays for each time interval), the insects were transferred to Petri dishes, in which recovery was recorded at different time intervals (2 h, 1, 2 and 7 days). The majority of susceptible populations of all species were instantly immobilized even in the shortest exposure period (15 min), in contrast with resistant populations that were active even after 300 min. After exposure to phosphine, populations and exposure time affected mortality of susceptible populations, whereas resistant populations recovered regardless of species and exposure time. Additional bioassays at the concentrations of 500, 1000, 2000 and 3000 ppm for 1, 3, 5, 20, 30 and 40 h showed the presence of the "sweet spot", i.e., decrease of mortality with the increase of concentration. In fact, for most of the tested species, the "sweet spot" appeared in 1000 and 2000 ppm at a 5-h exposure time, regardless of the level of resistance to phosphine. This observation is particularly important both in terms of the assessment of resistance and in the context of non-linear recovery at elevated concentrations, indicating the occurrence of strong hormetic reversals in phosphine efficacy.

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Section: Discussionsupporting

confidence: 93%