Tolerance of codling moth, and apple quality associated with low pressure/low temperature treatments

Abstract

A combination of low pressure (LP) and low temperature (LT) may serve as a phytosanitary disinfestation treatment for fresh fruit. In this study, different life stages of codling moth (eggs, 2nd to 3rd instar larvae, 5th instar larvae and pupae) were treated in hypobaric chambers maintained at 10°C and 1.33kPa with nearly saturated humidity (>98%). Weight loss, color, firmness, titratable acidity (TA), and soluble solids content (SSC) were selected as quality parameters to evaluate the quality changes of ‘Red Delicious’ apples before and after the LPLT treatment. Results showed that the 5th instar larvae were the most tolerant life stage for codling moth under LPLT treatment conditions. Insect mortality increased with increasing LPLT treatment time to >98% after 12 days of exposure to 10°C temperature and 1.33kPa pressure. Although stored in less than optimum conditions for apples, the measured quality variables of ‘Red Delicious’ were maintained relatively well after 15 days of LPLT treatment. The results suggest that LPLT technology has potential as an alternative, non-chemical disinfestation treatment for apples.