Heat Tolerance of First Instar Oriental Fruit Fly Infested in 'Nang Klarngwan' , 'Nam Dorkmai' , 'Rad' and 'Pimsen Daeng' Mangoes

Abstract

The first instar Oriental fruit fly (OFF), Dacus dorsalis Hendel, infested in 'Nang Klarngwan', 'Nam Dorkmai', 'Rdad' and 'Pimsen Daeng' mangoes (Mangfera indica Linn.). were determined for their heat tolerance by subjecting a npair of infested mango wvarieties to vapor heat. All available evidence indicated that there were some differences in the OFF first instars susceptibility to vapor heat treatment of 'Nang Klarngwan', 'Nam dorkmai', 'rad' and 'Pimsen Daeng' mangoes. The sruslts distinctively demonstrated that the OFf first instars in 'Pimsen Daeng' infested fruit for vapor heat evaluation showed that the first instar larval inoculation method was the most effective.
The differences observed in the OFF first instrs tolernce to vapor het treatment for different mango varieties would possibly effect the efficacy of the quarntine treatment currently used. Some OFF first instars infested in 'Pimsen Daeng' mangoes were able to survive whwn an approved vapor heat disinfestation treatment temperature 46.5 C for 10 min. at fruit center of 'Nang Klarngwan' mangoes was applied. Thus, it was neccessary to verify the efficacy of an approved vapor heat treatment of 'Pimsen Daeng' mangoes infested withthe OFF first instars.