EFFECTS OF OXYGEN, CARBON-DIOXIDE, AND TEMPERATURE ON THE MORTALITY RESPONSES OF EPIPHYAS-POSTVITTANA (LEPIDOPTERA, TORTRICIDAE)

First-instar light brown apple moths, Epiphyas postvittana (Walker), were exposed to various controlled-atmosphere treatments at different temperatures. The time required for 99% mortality (LT99) was highly dependent on the concentration of O2 and temperature; insects died more rapidly with lower concentrations of O2 and with higher temperatures. The effect of different concentrations of CO2 on mortality of first instars was less pronounced. At 20-degrees-C and an O2 concentration of 0.4%, a CO2 concentration of 5.0% resulted in lowest LT99 (mean of 22.5 h) of all of the CO2 concentrations tested. Using this atmosphere (i.e., 0.4% O2, 5.0% CO2), we determined mortality of third instars, fifth instars, and eggs of E. postvittana at 20 and 30-degrees-C. At both temperatures, LT99S decreased in the following order: fifth instar > third instar almost-equal-to eggs > first instar. An experiment testing this atmosphere at 40-degrees-C on fifth instars gave a mean LT99 of 4.2 h.