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 CO 2 was observed to be a direct consequence of egg mortality. Adult emergence was inversely related to the CO 2 concentration to which the eggs were exposed. The response of liposcelid eggs to hypercarbia (30–95% CO 2) did not differ from the simple Ct relationship, Ct = k. Eggs of Liposcelis bostrychophila were noted to be > 2 times more tolerant to CO 2 treatment than those of L. entomophila. Based on LT 50 and LT 95 values for 1-to 3-wk-old females exposed to 45 and 60% CO 2, L. bostrychophila was the more tolerant species. Increasing the CO 2 concentration from 45 to 60% did not reduce the LT 95 in either species. At a fixed exposure period of 4 h, no corresponding increase in mortality was observed in either species for CO 2 concentrations > 45%. Similar responses were observed in L. bostrychophila for 3 and 5 h exposures to various CO 2 concentrations. The use of CO 2-enriched atmospheres in the control of L. bostrychophila and L. entomophila is also discussed.