Multi-species comparisons for in vitro tolerance of quarantine tephritids to heat treatments

Phytosanitary treatments are often essential to prevent movement of invasive tephritid fruit flies from quarantine areas. Developing treatments can be time consuming and often the treatment is required immediately when an invasive tephritid is discovered and an area falls under quarantine. A proactive approach is to determine species’ relative tolerance to phytosanitary treatments. Species found to be no more tolerant than species for which treatments already exist could arguably be controlled with those existing treatments. Heat is a treatment option that’s applicable to a number of tropical fruit flies and commodity combinations. Heat treatment is currently used for almost all mangoes entering the US, papayas from Hawaii to the US mainland, and many fruits imported to Japan. There are, however, a number of challenges to working with fresh produce and developing insect infestation techniques to test phytosanitary treatments. Host fruit type, quality, size, ripeness, shape, country of origin and the insect species biological characteristics must all be considered in designing experiments that contribute to the development of approved treatment schedules.  Here we report on the development of an “artificial fruit” bioassay used to evaluate heat treatments for a number of tephritids of quanrantine significance, and present results of comparative in vitro heat tolerance of species of tephritid fruit flies.