Location: Tropical Crop and Commodity Protection Research
Project Number: 2040-43000-018-046-I
Project Type: Interagency Reimbursable Agreement
Start Date: Aug 1, 2024
End Date: Jul 31, 2027
Objective:
The overall goal of this project is to identify volatile compounds (odors) of oriental fruit fly that can be used to evaluate any differences between colony and wild giant OFF as well as other fruit fly species. Any unique compounds identified will be explored for use as canine training aids in locations where live OFF are not available.
The specific objectives of this project for ARS-Hilo are to:
1) Isolate and identify volatile compounds from various OFF larval and pupal sources or forms.
2) Evaluate OFF detector dog responses to various OFF and non-OFF fruit fly larvae and pupae.
3) Determine unique OFF compounds that differ from at least two other fruit fly species found in Hawaii.
4) Develop a synthetic training tool using compounds unique to OFF and evaluate OFF detector dog response to the prototype training tool.
Approach:
Field Collection of wild OFF, melon fly and medfly in Hilo, Hawaii
Wild fruit fly infested host fruits of OFF (e.g. guava, Indian almond), melon fly (e.g. papaya), and medfly (e.g. papaya, coffee) will be obtained from different locations known to have infestation from these flies. Infested host fruits will be brought back to the lab to rear 2nd and 3rd instar larvae and pupae for volatile profile analysis. A part of naked larvae and pupae collected will be frozen at -20C for volatile analyses of frozen then thaw samples. Infested fruit and bagged fruit (to prevent infestation) will be also collected for volatile analyses.
Odor analysis
The volatile profile of different life stages (3rd instar larvae, pupae), fresh or frozen samples, and naked larvae vs larvae in fruit will be determined using Thermal Desorption-GC-MS (Markes TD100-xr Thermal Desorption with Agilent 8890 GC and 5977B MS) equipped with non-polar DB-5MS or polar DB-Waxetr capillary columns (30 m x 0.25 mm diameter x 0.25 um film thickness). Fruit fly compounds will be identified based on library matches, retention index, and also using authentic standards if commercially available. Volatile profiles of OFF will be compared with odor profiles of other invasive fruit flies such as melon fly and medfly by checking absence and existence of certain compounds among different sample types. A mixture of the volatile compounds unique to OFF will be prepared for testing with canine unit.
Oriental fruit fly odor dispensers
A mixture of the commercially available volatile compounds unique to oriental fruit fly odors will be prepared using neat compounds and loaded to different types of dispensers for testing with OFF trained canines. Dispenser types will include rubber septa, polyethylene vial, polypropylene vial, and different thickness and sizes of polyethylene sachets.
