Responses of Woodchucks to Potential Garden Crop Repellents

Abstract

We conducted feeding trials with captive woodchucks (Marmota monax) to determine whether commercial repellents registered for use on edible crops (Hot Sauce Animal Repellent ®, Hinder ®), insecticides (Cygon ®, Sevin ®), or an emetic agent, emetine dihydrochloride, reduced consumption of plants grown in gardens. Application of Hot Sauce Animal Repellent on leaves of acorn and zucchini squash did not reduce consumption relative to pretreatment levels, and Hinder, Cygon, and Sevin were ineffective in reducing consumption of Romaine lettuce by woodchucks. When woodchucks were presented with 6 wild forage species as well as butternut squash leaves or Romaine lettuce, they reduced their consumption of Hinder-treated squash leaves but not Hinder-treated lettuce. Relative to the alternative forage species, butternut squash ranked low in palatability and Romaine lettuce ranked high; thus, a negative association existed between the effectiveness of Hinder and the relative palatability of the target species. Injection of cherry tomatoes with emetine dihydrochloride significantly reduced consumption after 11 days, and woodchucks subsequently generalized their conditioned aversion to untreated tomatoes for a 3-week period