Repellent activity of icaridin-impregnated horsecloth against horse flies.

Overview

• This study investigated the effectiveness of horsecloth treated with the repellent icaridin in reducing horsefly attacks on horses.
• The research demonstrated that icaridin-impregnated cloth significantly lowered horsefly numbers and horsefly-related avoidance behaviors compared to untreated or plain cloth.

Introduction and Background

• Horseflies are blood-sucking insects that cause discomfort to horses and can transmit diseases.
• They lead to economic losses in the equine industry due to stress and potential health problems in horses.
• Traditional control strategies include physical barriers (like cloth coverings) and chemical repellents.
• This study aimed to evaluate a combined approach: horsecloth impregnated with icaridin, a known insect repellent.

Study Design and Methods

• Location: Riding horse club in Hokkaido, Japan, in July 2023.
• Subjects: Six horses were used – three native Hokkaido horses (Dosanko) and three mixed breeds (Dosanko and Haflinger).
• Treatments tested:
• Treatment 1: No horsecloth (control).
• Treatment 2: Horsecloth without icaridin (physical barrier only).
• Treatment 3: Horsecloth impregnated with icaridin (chemical repellent + barrier).
• Measured outcomes included the number of horsefly attacks and horse avoidance actions (behaviors to evade flies).

Key Findings

• Treatment 3 (icaridin-impregnated cloth) significantly reduced the number of horseflies compared to untreated or plain cloth.
• Treatment 2 (plain cloth) did not significantly reduce the number of horseflies compared to no cloth.
• Both treatments 2 and 3 reduced horse avoidance behaviors, indicating that the cloth itself provided some comfort.
• The reduction in avoidance behaviors was greater with icaridin treatment, suggesting better fly deterrence and reduced irritation.
• Horses with lighter coat colors experienced fewer fly attacks and avoidance behaviors than darker-colored horses, indicating potential color-related attractiveness to horseflies.

Conclusions and Implications

• Using cloth impregnated with icaridin is more effective in repelling horseflies than using cloth alone.
• The combination of chemical repellents with physical barriers enhances horsefly control strategies, improving horse comfort and welfare.
• Reducing fly attacks can also improve the safety of horses as fly irritation often leads to sudden movements and potential injuries.
• This suggests practical applications for equine management, especially in environments with high fly populations.

Recommendations for Future Research

• Further studies with larger horse populations are needed to confirm these findings.
• Assessment of efficacy across various horse breeds and different environmental conditions should be conducted.
• Long-term effects and optimal impregnation concentrations of icaridin on horsecloth could be evaluated.