Sieving Fruit Pulp to Detect Immature Tephritid Fruit Flies in the Field

We are developing a method to find tephritid fruit fly larvae that is faster and more accurate than the current method of cutting and visually inspecting each fruit. We want to develop a simple technique that can be used in the field to process large amounts of fruit. A challenge of this study was finding fruit with a low infestation, which would likely represent what we see during an emergency or eradication program.

As we cannot see into the fruit, we use methods to artificially infest key hosts with a low number of larvae. In both field and laboratory trials, mushing and sieving the pulp require less time, and more larvae were found than cutting fruit. Floating the pulp in a brown sugar water solution helped detect earlier instar larvae.

Mushing and sieving fruit pulp of important tephritid hosts may increase the probability of detecting larvae during emergency programs. We'll continue to optimize the protocol to determine the optimal sieve size for different species of regulated fruit flies and establish criteria such as the type of fruit, the quantity of fruit, et cetera, that will help decide whether the use of the larval destruction method or standard fruit cutting is warranted.