Post-harvest mortality of carob moth in date fruit using temperature and time

Since the removal of methyl bromide for post-harvest treatment of carob moth-infested dates, packers have used cold and hot treatments to kill eggs and immatures in their dates. Using Deglet Noor and Medjool date varieties, we evaluated the mortality of eggs, small and large larvae in infested dates at -5°F, 0°F, 10°F, 20°F, 32°F, 40°F, 45°F, 50°F and 130°F. Infested dates were exposed for varying amounts of time depending on temperature. For all temperatures below 32°F, carob moth eggs and small larvae died within 24 hours. At 32°F, all eggs were dead by day 7 and 4 for Deglet Noor and Medjool dates, respectively. Small larvae died in 3 days in the Deglet Noor dates, and 2 days in the Medjool dates. Large larvae lived longer with 100% mortality at 8 days for both date varieties. At 40 and 45°F, mortality occurred in eggs by days 9 and 10, but larvae survived longer. At 50°F eggs in Deglet Noor were all dead in 11 days, but the small and large larvae in Deglet Noor and all life stages in the Medjool survive for at least 22 days. At 130°F, all life stages in both varieties were dead after 2 hours of exposure.  These data are being used to provide recommendations to date packers to assist in post-harvest treatment of carob moth-infested dates.