Effect of extreme low and high temperatures on the almond moth, Ephestia cautella (Walker) (Lepidoptera: Pyralidae)
Y. A. Darwish, A. M. Ali, R. A. Mohamed, N. M. Khalil
Journal of Phytopathology and Pest Management
Abstract: The different immature stages of the almond moth, Ephestia cautella (Walker) were exposed to low temperature of -5oC for different exposure times. Exposure of eggs to 240 to 360 minutes is sufficient to achieve 100% mortality for this stage. Exposed early larval instar to -5oC for 180 minutes is sufficient to achieve 100% mortality. Exposure of the late larval instars to 300 and/or 360 minutes is effective to achieve a complete mortality for the late larval instars of the pest. The calculated LT50 and LT95 were 113.73 and 208.64 minutes. Exposure of pupae to 300 minutes or more is effective to get a complete mortality for the pupal stage. High temperatures of 45o, 50o, 55o and 60oC were tested against egg, late larval instars and pupal stages of E. cautella. Mortality tended to be increased with the increasing of temperature and exposure time. Exposure time for more than one hour at 45oC, 15 minutes at 50oC and 10 minutes at 55oC were more effective and led to more than 95% mortality for the egg stage of E. cautella. Exposure of the late larval instars for more than 97.22, 72.17, 17.65 minutes at 45, 50 and 55oC is sufficient to achieve more than 95% mortality for the late larval instars as indicated by LT95 values. Exposing the pupae to 25 minutes at high temperatures of 50oC and to 15 minutes at 55oC is an effective to get complete mortality for the pupal stage. Thus exposure times for more than 90 minutes at high temperature of 45oC; 33 minutes at 50oC and/or 11.67 minutes at 55oC were more effective to achieve more than 95% mortality of the pupal stage of E. cautella.