THE RESPONSE OF LIPOSCELIS-BOSTRYCHOPHILA BADONNEL AND LIPOSCELIS-ENTOMOPHILA (ENDERLEIN) (PSOCOPTERA) TO PHOSPHINE

Eggs and adults of Liposcelis bostrychophila were exposed to fixed phosphine concentrations for varying exposure periods. The eggs were more tolerant of phosphine than the adults, but the former showed no change in tolerance with age. Phosphine may have arrested development of the eggs during exposure, as evidenced by delayed hatching of phosphine treated eggs. The response of L. bostrychophila eggs did not differ greatly from the simple relationship, Ct = k. When mixed-age cultures of L. entomophila were exposed to 0.1 mg l(-1) phosphine with varying exposure periods, the time to population extinction occurred at 96 h exposure. This dosage is similar to the LD(99) for L. bostrychophila eggs at this concentration. The current recommendations for the use of phosphine are adequate for controlling the two species studied.