RESUMEN
INTRODUCTION: Culicoides pachymerus is a major pest species for the inhabitants of the western Boyacá province of Colombia. OBJECTIVE: The effect of a repellent lotion based on p-menthane-3,8-diol (16%) and lemongrass oil (2%) was evaluated against the bites of C. pachymerus. MATERIALS AND METHODS: The repellent lotion was compared simultaneously with a control (no treatment) by human landing catches of C. pachymerus on the forearms of paired volunteers situated near human dwellings. Protection percentage and protection time for 3 to 6 h after repellent application was calculated. The test was repeated ten times. RESULTS: Only two females of C. pachymerus were collected on arms with the repellent treatment. In contrast, the mean biting rate in the untreated control was 47.7 midges/person/10 min. Mean protection percentage of the repellent was 100% up to 4 h and 99.5% up to 5 h. Protection time was 332.2 and 338.2 min in the two replicates where bites of C. pachymerus were confirmed. In the remaining eight replicates protection time exceeded the test duration. CONCLUSION: The repellent showed high efficacy against C. pachymerus, up to 5 h post-application.