Author(s): Nayak MK, Collins PJ
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Abstract BACKGROUND: The psocid Liposcelis bostrychophila Badonnel, is a widespread, significant pest of stored commodities, has developed strong resistance to phosphine, the major grain disinfestant. The aim was to develop effective fumigation protocols to control this resistant pest. RESULTS: Time to population extinction of all life stages (TPE) in days was evaluated at a series of phosphine concentrations and temperatures at two relative humidities. Regression analysis showed that temperature, concentration and relative humidity all contributed significantly to describing TPE (P<0.001, R(2)=0.95), with temperature being the dominant variable, accounting for 74.4\% of the variation. Irrespective of phosphine concentration, TPE was longer at lower temperatures and high humidity (70\% RH) and shorter at higher temperatures and low humidity (55\% RH). At any concentration of phosphine, a combination of higher temperature and lower humidity provides the shortest fumigation period to control resistant L. bostrychophila. For example, 19 and 11 days of fumigation are required at 15 degrees C and 70\% RH at 0.1 and 1.0 mg L(-1) of phosphine respectively, whereas only 4 and 2 days are required at 35 degrees C and 55\% RH for the same respective concentrations. CONCLUSIONS: The developed fumigation protocols will provide industry with flexibility in application of phosphine.
This article was published in Pest Manag Sci
and referenced in Entomology, Ornithology & Herpetology: Current Research