Repelling animals from crops using plant extracts

Abstract

Several plant species that are not consumed by animals were collected, extracted with organic solvents, and tested at different venues for their effectiveness as animal feeding repellents. Species with the most repellent activity were daffodil (Narcissus pseudo narcissus), bearded iris (Iris sp.), hot pepper (Capsicum frutescens), catnip (Nepeta cataria) and peppermint (Mentha piperita). Considerable effort was expended to isolate and identify compounds from these species responsible for repellent activity. Eight chemicals have been isolated and purified, and four of them have been identified. Both daffodil and catnip contain more than one repellent, but none of the four compounds identified were common to both species. Combinations of extracts from more than one plant species proved to have more repellent activity than extracts from individual species used alone. In several tests these plant extracts proved to be as effective or better than available commercial repellents. A plethora of additives and surfactants were tested to increase repellent activity by enhancing the spreading, penetration or persistence of the extracts.