Evaluation of Citronella for Repellency of Biting Arthropods on Horses, 1992

Eight thoroughbred mares (20 to 24 yrs old) were randomly assigned to one treatment group and one control (untreated) group (four mares per group). An experimental preparation of 10.6% citronella (Natrapel1) was applied to both sides (0.5 m2 area) of the horses in the treated groups with a hand pump mist sprayer. Each horse received 15 pumps per side or the equivalent of 120 ml for a whole body application. Three to five d old stable flies, horn flies, and two species of Aedes mosquitos (3-o 5-d-old) were tested by placing them in tea strainers (12.7 cm diam) and feeding them 10% sugar water for 24 h prior to exposure. Repellency was tested after a single treatment, two treatments in 1 d and 2 treatments/d for 2 d. After the treatments, the strainers containing separate species were placed on the sides of the horses and held in place by elastic straps for 15 min at 1, 4, 18, 24, 48, and 72 h posttreatment. After exposure the insects were frozen at - 10°C and squashed on paper toweling to determine if a blood meal had been acquired. Data were subjected to analysis of variance (ANOVA). Differences among means were considered significant at P < 0.05.