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Evaluation of Knockdown Bioassay Methods to Assess Phosphine Resistance in the Red Flour Beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae)

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Cato, A., Afful, E., Nayak, M. K. and Phillips, T. W. (2019) Evaluation of Knockdown Bioassay Methods to Assess Phosphine Resistance in the Red Flour Beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). Insects, 10 (5). p. 140. ISSN 2075-4450


Article Link: https://doi.org/10.3390/insects10050140

Publisher URL: http://www.mdpi.com/2075-4450/10/5/140


Resistance to the fumigant phosphine in Tribolium castaneum occurs worldwide. This study evaluated tests based on adult knockdown time, the time for a beetle to become immobile, when exposed to a high concentration of phosphine. We recorded knockdown times of beetles that remained completely still for 30 s when exposed to 3000 ppm of phosphine in a large, gas-tight glass tube. Beetles were used from 12 populations, of which six were ‘susceptible’ to phosphine, three were ‘weakly resistant’, and three were ‘strongly resistant’. Knockdown times were determined for single beetles, as well as for groups of ten beetles for which the time to knockdown for either five beetles (KT50) or ten beetles (KT100) were recorded. Similar knockdown times occurred across susceptible and resistant populations. However, the KT100 tests generated conservative times for diagnosing strong vs. weak resistance. The strong resistant populations were all over 100 min with KT100, compared to 60 min or less for susceptible and weak resistant populations. Special tests on single beetles revealed higher knockdown times in insects that were deliberately disturbed compared to those without any disturbances. Work reported here suggests a knockdown test conducted on beetles in a matter of minutes or hours could help classify phosphine resistance status prior to decisions on phosphine fumigation.

Item Type:Article
Business groups:Crop and Food Science
Additional Information:Open access
Keywords:fumigation; hydrogen phosphide; narcosis; resistance management; stored products
Subjects:Science > Entomology
Plant culture > Field crops > Grain. Cereals
Plant pests and diseases
Plant pests and diseases > Pest control and treatment of diseases. Plant protection
Live Archive:30 May 2019 05:52
Last Modified:03 Sep 2021 16:45

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