Can Synthetic Scent of Predators 

 Repel Deer in Orcliards? 



Ronald Prokopy and Jennifer Mason 



Department of Entomology, University of Massachusetts 



There is a growing number of studies suggesting 

 that predator odors are repellent to potential prey. 

 Repellency appears to stem at least in part from chemi- 

 cal constituents of predator urine or feces. Deer can be 

 very troublesome pests in apple orchards, especially 

 during winter months, when they chew apple buds and 

 twigs. Cougars and other large members of the cat 

 family are among predators which deer fear the most. 

 We report here on a small pilot study that we conducted 

 to evaluate potential repellency to deer of synthetic odor 

 of cougar feces. 



Materials and Methods 



TTie odor consisted of a 50:50 mixture of 3-propyl- 

 1 ,2-dithiolane and 2-propylthietane, encapsulated in 

 polymeric plastic fibers to provide slow release. Both 

 components of this mixture are present in cougar feces. 

 Together, they convey a strong sulfur-like stench 



vaguely similar to the smell of a skunk but more 

 pungent. The odorous fibers are still in a developmental 

 stage, not yet available commercially. They were 

 provided to us by Phero Tech Inc. of Delta, British 

 Columbia. 



In November of 1992 and December of 1993, we 

 hung 4 fibers on each of 25 perimeter-row apple trees at 

 Rice's fruit farm in Wilbraham, Massachusetts. Each 

 tree with fibers was separated by three perimeter-row 

 trees without fibers, the middle tree of which served as 

 the check tree. Ten twigs on each treated and check tree 

 were examined for signs of deer injury just before 

 emplacement of fibers and again one to three months 

 afterward. 



Results and Conclusions 



The data in Table 1 show there was little if any 

 repellent effect of the odorous fibers against deer feed- 



Fruit Notes, Fall, 1994 



17 



