Freezing temperature treatments against almond moth, Ephestia cautella (Walker), infestation of date fruits

Abstract

Dates maintain prime importance as sources of income and as symbols of cultural heritage in Saudi Arabia. Ephestia cautella (Walker) is one of the most important insects that attack stored dates. In an effort to safeguard small-scale producers, temperatures of 5 °C (representing typical house refrigerator temperatures), − 14 °C (representing in-house freezer temperatures), and − 25 °C (representing temperatures in small factory freezers) were applied to samples of dates previously infested with E. cautella larvae. Exposure periods of 1, 12, 48, 120, and 240 h were considered to assess the effectiveness of freezing temperatures against stored product insect pests. The temperature of − 25 °C proved to be the most effective, resulting in 100% mortality across all stages after just 1 h of exposure. At 5 °C, the pupal stage exhibited the highest tolerance, with only a mean mortality of 11% after 240 h of exposure. Conversely, at the same temperature, mean mortalities of 89% and 97% were recorded for eggs and larvae, respectively. However, when larvae were placed inside the dates, the mean mortality was only 65% after 240 h at 5 °C, complete larval mortality was achieved in 12 h at − 14 °C and 1 h at − 25 °C. This information can guide strategies for managing E. cautella in storage facilities with limited available resources.