477 Effect of High-temperature Controlled-atmosphere Treatments for Insect Control in `Bartlett' Pear Fruit

Abstract

High-temperature, controlled-atmosphere treatments were explored for disinfestation of codling moths from `Bartlett' pear fruit. Fruit were freshly harvested in 1996 and 1997 and sorted for uniformity and absence of defects. Fruit were exposed to forced-heating at 46 °C for 1, 2 and 3 h in either air or a controlled atmosphere of 1% oxygen and 15% carbon dioxide. Fruit were evaluated during ripening at 20 °C immediately after treatment (1997 only) and after 3 weeks of cold storage at -1 °C. Fruit were ripened with and without an exogenous ethylene treatment in 1997. Heat treatments, and particularly heat plus CA treatments, slowed fruit ripening, even after fruit had been stored for 3 weeks. The longer the treatment, the greater the inhibition. Fruit from longer treatments were firmer than untreated fruit after 4 days of ripening, but treatment with exogenous ethylene did not overcome the inhibition in the rate of ripening, although fruit from all treatments softened faster. The mortality of codling moths following exposure to the same treatments was also determined. With the heat plus controlled-atmosphere treatments, 100% mortality was achieved in 2.5 h with the faster heating rate used in our 1996 experiment, while it took 3 h to achieve 100% mortality with the slower heating rate.