title: Inhibition of egg development by phosphine in the cosmopolitan pest of stored products Liposcelis bostrychophila (Psocoptera: Liposcelididae).
abstract: Phosphine-induced delay in development of eggs was investigated as a mechanism of resistance to this fumigant in Liposcelis bostrychophila Badonnel. One-day-old eggs of a susceptible and a strongly resistant strain of L bostrychophila were exposed to a range of phosphine concentrations for 6days at 30 (+/- 1) degrees C and 70 (+/- 2)% RH. Delay in mean hatching period occurred in both susceptible and resistant eggs, although it was more pronounced in the latter. A maximum delay of 2.65 days was recorded for eggs of the susceptible strain at 0.01 mg litre(-1) (the highest concentration at which eggs survived) and 13.39 days for the resistant strain at 1 mg litre(-1) (the highest concentration tested). Delay in egg development time was positively correlated with increasing phosphine concentration. Our results reveal that the most successful strategy to control resistant L bostrychophila is to apply relatively low concentrations of phosphine for extended exposure times (eg 0.05 mg litre(-1) for 16 days) that allow all eggs to hatch to the much less tolerant nymph stage.
authors: Queensland Department of Primary Industries, 80 Meiers Road, Indooroopilly, QLD 4068, Australia. manoj.nayak@dpi.gld.gov.au
authors: Manoj K
authors: MK
authors: Nayak
authors: Patrick J
authors: PJ
authors: Collins
authors: Hervoika
authors: H
authors: Pavic
authors: Rosemary A
authors: RA
authors: Kopittke
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D005260:Female; D005651:Fumigation; D007300:Insect Control; D007313:Insecta / Q000187:drug effects / Q000502:physiology*; D007305:Insecticide Resistance / Q000502:physiology; D007306:Insecticides / Q000494:pharmacology*; D010063:Ovum / Q000187:drug effects*; D010720:Phosphines / Q000494:pharmacology*; D014908:Triticum
chemical_list: D007306:Insecticides; D010720:Phosphines; C044646:phosphine