Vapor heat mortality tests on the eggs of oriental fruit fly, Bactrocera dorsalis, infesting different fruit shape of fresh mango.
Omura K., Dohino T., Masahiro Tanno I. M., Suzuki N.
Author Affiliation: Research Division, Yokohama Plant Protection Station, 1-16-10 Shin-yamashita, Naka-ku, Yokohama 231-0801, Japan.
Research Bulletin of the Plant Protection Service, Japan : 1-8
Abstract : Three different mango varieties, Tommy Atkins' (oval/round shape, 431.5-575.7 g), 'Nam Doc Mai' (flat/elongated shape, 379.1-444.5 g), 'Carabao' (flat/elongated shape, 217.8-241.9 g), infested with eggs of Oriental Fruit Fly, Bactrocera dorsalis (Hendel) were subjected to vapor heat treatment to study the relationship between mango variety and mortality. The innermost pulp of each variety was heated to 45.5°C. The result showed that the heavier the fruit weight, the longer the run-up time and the higher the mortality. When the 'Nam Doc Mai' reached 45.5°C, 'Tommy Atkins' was 42.8-44.2°C. However, the mortality of eggs in 'Tommy Atkins' was higher than those in 'Nam Doc Mai'. We speculate that this was because heavy and oval Tommy Atkins kept surplus heat longer than 'Nam Doc Mai'. We supposed that fruit shape affected the heat loss after treatment, but it could not be denied that fruit weight affected heat loss. Then, nearly the same weight and different shaped mangoes, 'Nam Doc Mai' (flat/elongated shape, 429.1 g-480.9 g) and 'Kent' (oval/round shape, 427.8-480.9 g) were heated to 45.0°C. The result showed that increase and decrease in temperature of 'Nam Doc Mai' was faster and the mortality of B. dorsalis eggs in 'Nam Doc Mai' was lower than 'Kent'. These results indicated that the fruit shape was one of the factors which affect mortality in vapor heat treatment.