Preliminary Field Efficacy of Anthraquinone Repellent to Reduce Drip Irrigation Line Damage by Cottontail Rabbits

Author(s): Anderson, Christopher T.; Major, Matthew; Blake, Alan; Raff, Collin; Quinn, Niamh M. | Abstract: Unmanaged cottontail rabbit populations can cause significant damage to drip irrigation tubing. Common integrated pest management strategies to reduce damage include trapping, exclusion, and repellent use. Trapping and exclusion, while effective at managing cottontail rabbits, are impractical when applied to large scale habitat restoration projects. To evaluate repellent use under these conditions, we conducted a preliminary conditioned avoidance field trial using anthraquinone applied to drip irrigation tubing installed in a riparian habitat undergoing restoration in Silverado, CA. The postingestive repellent, anthraquinone, was selected due to prior laboratory research indicating its effectiveness in inducing conditioned avoidance feeding behaviors in cottontail rabbits. Following a complete repair of the irrigation system, alternating sections of the irrigation tubing were treated. After the first treatment, there was an estimated 50% reduction in damaged tubing between the treated and control sections. An estimated 0.18% of the total tubing surveyed was damaged after the second treatment. Between the first and second treatments, we observed an estimated 99.5% decrease in total damaged tubing. Our results suggest that anthraquinone may be successful in reducing cottontail rabbit damage by inducing conditioned avoidance to drip irrigation line. As a preliminary study, these findings are promising and warrant future field trials to validate the use of anthraquinone as a repellant to reduce damage by cottontail rabbits.