Abstract
The efficacy of CO2 and N-2 gases alone or in a mixture was tested against eggs, larvae, and pupae of the almond moth, Cadra cautella, a major date fruit pest, under temperature regimes of 5 degrees C and 25 degrees C. Our results indicated that exposing different stages to higher concentrations of CO2 significantly affected egg hatchability, larval mortality, and pupal mortality as compared to 100% N-2 gas, at both temperature regimes. Application of CO2 at lower doses (below 50%) did not give 100% mortality of any developmental stage even at longer exposure timings. However, treatments at higher doses (75 and 100% CO2) were effective at 24 h and longer treatment duration. The application of 100% N-2 did not effectively control C. cautella. Of all the stages, the larvae of C. cautella were most susceptible to the gases. Our results indicated that temperature has a significant effect on the efficacy of gases or their combinations tested after an exposure of 48 h and longer. Based on current findings, we conclude that CO2 gas is a good candidate for successful control of C. cautella immature stages under storage conditions and can be a potential alternative to highly toxic methyl bromide.