Quick knockdown results in high mortality: is this theory correct? A case study with phosphine and the red flour beetle

BACKGROUNDThe fumigant phosphine is used all over the world for disinfestation of stored grains and commodities. Adults of 23 different populations of Tribolium castaneum from 10 different countries were evaluated for phosphine resistance using a modification of the Detia Degesch Phosphine Tolerance Test Kit (DDPTTK). Adults were exposed to 3000 ppm and recorded for 5-270 min for their mobility. RESULTSAmong the tested populations, high levels of phosphine resistance were recorded in populations from Brazil, Serbia, and Spain. No survivals were recorded after 7 days post exposure for eight of 23 in a tested population. CONCLUSIONSOur work revealed four scenarios: 1, quick knockdown-low (or no) recovery; 2, Slow knockdown-high recovery; 3, Quick knockdown-high recovery; and 4, Slow knockdown-low recovery. Our data indicate that post exposure period is critical for the evaluation and characterization of phosphine resistance. (c) 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Automated summary

Phosphine resistance was evaluated in 23 populations of Tribolium castaneum from 10 different countries. High levels of resistance were found in populations from Brazil, Serbia, and Spain. Eight populations showed no survival after 7 days post exposure.