The most time-consuming and expensive assay for repellents or repellent devices is the field test. For this test an experimenter is set up in the field within mosquito habitat at times when mosquitoes are most active. The experimenter wears a protective suit that only exposes the arms. A second experimenter catches all mosquitoes that land on the test person using an aspirator.
This assay can be used to test the efficacy of spray-on repellents, lotions, repellent devices, or repellent-treated clothing.