AN EVALUATION OF REPELLENTS TO SUPPRESS BROWSING BY POSSUMS

The efficacy in feeding suppression trials with possums (Trichosorus v ulpecula Kerr) of six synthetic odorous chemicals uniquely associated with various of the Mustelidae species and of the red fox (Vulpes vulp es) has been evaluated with respect to several proprietary repellents. The predator odors, two proprietary repellents, and two other repelle nt formulations (olive oil in petroleum jelly and a synthetic fermente d egg odor cocktail) were applied as 5% w/v solutions In paraffin to t he foliage of Pinus radiata seedlings and the extent of browse compare d with that on seedlings treated with Treepel, an effective egg-based repellent already available commercially. All four of the mustelid pre dator odors [(-/+)-2-n-propylthietane, (-/+)-3-n-propyl-1.2-dithiolane , 2,2-dimethylthietane, and 3,3-dimethyl-1,2-dithiolane] and the volat ile compound from fox urine (Delta(3)-isopentenyl methyl sulfide) were shown to be more or at least equally effective compared to Treepel. T his was true also of one commercial repellent Gori, which contained bi trex and the synthetic fermented egg formulation. The most effective c ompounds will be evaluated when administered with adhesives and surfac tants in the further development of possum repellents with longer fiel d lives.