Inhibition of egg development by phosphine in the cosmopolitan pest of stored products Liposcelis bostrychophila (Psocoptera: Liposcelididae).
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.
Nayak
Manoj K
MK
Queensland Department of Primary Industries, 80 Meiers Road, Indooroopilly, QLD 4068, Australia. manoj.nayak@dpi.gld.gov.au
Collins
Patrick J
PJ
Pavic
Hervoika
H
Kopittke
Rosemary A
RA
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
D007306:Insecticides; D010720:Phosphines; C044646:phosphine