Effects of carbon dioxide on the mortality of Liposcelis bostrychophila Bad. and Liposcelis entomophila (End.) (Psocoptera: Liposcelididae)

Abstract

The reduction in adult emergence of Liposcelis entomophila eggs treated with CO2 was observed to be a direct consequence of egg mortality. Adult emergence was inversely related to the CO2 concentration to which the eggs were exposed. The response of liposcelid eggs to hypercarbia (30-95% CO2) did not differ from the simple Ct relationship, Ct = k. Eggs of Liposcelis bostrychophila were noted to be > 2 times more tolerant to CO2 treatment than those of L. entomophila. Based on LT50 and LT95 values for 1-to 3-wk-old females exposed to 45 and 60% CO2, L. bostrychophila was the more tolerant species. Increasing the CO2 concentration from 45 to 60% did not reduce the LT95 in either species. At a fixed exposure period of 4 h, no corresponding increase in mortality was observed in either species for CO2 concentrations > 45%. Similar responses were observed in L. bostrychophila for 3 and 5 h exposures to various CO2 concentrations. The use of CO2-enriched atmospheres in the control of L. bostrychophila and L. entomophila is also discussed. © 1995.