Irradiation to control insects in fruits and vegetables for export from Hawaii

Abstract

Phytosanitary or quarantine treatments are often required to disinfest host commodities of economically important arthropod pests before they are moved through market channels to areas where the pest does not occur. Irradiation is an accepted treatment to control quarantine pests in 10 fruits and five vegetables for export from Hawaii to the US mainland. Irradiation is the ideal technology for developing generic quarantine treatments because it is effective against most insect and mite pests at dose levels that do not affect the quality of most commodities. A generic dose of 150 Gy has been proposed for tephritid fruit flies. Contrary to the 150 Gy dose, approved irradiation quarantine treatment doses for Mediterranean fruit fly, melon fly, and oriental fruit fly in Hawaii are 210–250 Gy. Irradiation studies were conducted to determine if the approved doses were unnecessarily high and could be reduced. Irradiation is also a viable alternative to methyl bromide fumigation to disinfest Hawaii sweetpotatoes, and studies are in progress to identify an effective dose for two key sweetpotato insect pests. Results indicate that irradiation doses <150 Gy will control Hawaii's fruit flies, which supports the proposed generic dose. The idea of generic doses is appealing because it would greatly accelerate the process of approving irradiation quarantine treatments for specific crops, and thereby rapidly expand exports. Preliminary results show that 250–300 Gy will control Hawaii's sweetpotato pests.