DEER REPELLENT STUDY

At Illinois Walnut Council Butternut Plot

 By Ken Konsis

The Illinois Walnut Council planted butternut seedlings in 1994 at the Tree Research Area, Forest Glen Preserve, Westville, IL. This is also the IWC Headquarters. Butternut (Juglans cinerea) were chosen in response to the declining butternut species due to the Butternut Canker fungus (Sirococcus clavigignenti-juglandacearum.)  The butternut plot consists of 14 rows of trees with 17 trees per row, or 238 total number of trees. Height measurements and herbicide treatments have been performed since the second year the seedlings were in the ground. Pruning of the trees was performed in the winter of 2001.  The plot was overall heavily browsed by deer and had several major buck scrapes. This seemed to be the perfect area for a deer repellent study, especially since the Walnut Council receives many inquiries about repellents. The Vermilion County Conservation District has already conducted deer fencing studies and deer browse studies at the Tree Research Area. The results of the fencing study was part of the Walnut Council Annual Meeting tour in 1998. These results were very positive.

The products that were chosen to be part of this study are products that are readily available from nursery and garden catalogs. The Vermilion County Conservation District and the Illinois Walnut Council do not endorse any of these products. The attempt is to report on findings of this study. Also, some products recommend multiple applications (after rains, etc.) This was not done. All products were treated the same. They were applied on the same day and results were documented on the same day. It is quite possible that the results would be different if complete product directions were applied. This, however, was not feasible due to lack of manpower, time restraints, and everything else that enters into one’s busy schedule. Therefore, this is not applied research but may be comparable to what a landowner would do.

The following is a listing of products tested using the brand name, active ingredient, quantity purchased, price paid, and general application and information on the product label.

PRODUCT TESTED
 

           MECHANICAL CONTROL TESTED

   PRODUCTS TO BE TESTED 

Of the 238 total trees in the plot, at least 2 trees not affected by deer browse or scrapes were chosen for each product. Six (trees) were surrounded by 48-inch woven wire fencing. The average height of the trees is 5 feet 3 inches.  

GENERAL ASSESSMENTS AND OBSERVATIONS

There were originally 238 butternut seedlings planted in 14 rows with 17 trees per row. Of these original trees, only 112 or 47% are currently surviving. This has not changed since the beginning of this study in 1999. Of the 112 surviving trees, 35 are a part of the deer repellent study. The remaining trees (77) can be considered “control” trees. Of these control trees, 71 trees were damaged be deer. Only 6 trees showed no damage. Of the 35 trees in the study, only 10 trees showed deer damage in some way. Therefore, it is probable that these repellents do work.

Conclusions

First and foremost, deer repellents are very expensive to use and are labor-intensive to apply. The results are not guaranteed and depend on many factors such as time of year applied, weather conditions, application rate, following exact label directions, suggested re-applications, and the total number of trees to be protected. Product active ingredients must be examined closely, but this is usually unknown when ordering from a garden or nursery catalog.  An example of this is the product “Tree Guard Deer Repellent” which is yet to be tested in this study. It was purchased for $44.95 per gallon. When examining the active ingredients, it is exactly the same as a product already tested, “Durapel”. The price for Durapel, however, was $29.99 per gallon.

Before applying a deer repellent, ask yourself these questions:

1. How many trees do I wish to protect?

2. Is cost a factor?

3. Do I have the time to apply the repellents?

4. Will I be satisfied with mixed results?

Sometimes it is better to try and understand the deer. Deer are basically lazy animals that often use the same trails or paths. Along these paths (deer runs) you usually notice the most deer damage on trees (buck rubs or browse damage.) It is also easy to notice if deer are bedding down in the plantation at night. Deer damage is usually severe here. Our experiment with deer fencing worked because deer did not bother to jump a 48-inch fence, although they could do so easily without any effort. It also worked because we fenced in a small area of trees. A larger area would be ineffective unless a taller fence would be installed (costly.) If you have a favorite tree to protect, we have had great success by enclosing the single tree with fence wire, forming a cylinder. This protects trees from deer rubs, but not browsing. If the tree branches reach 4 feet in height, this will be above the browse line and the problem is gone. The key is to get the tree above that height. Annual browsing forms “bushy” trees. Deer also tend to rub on smooth barked trees. Young trees of all species fall into this category. When trees mature and form rougher bark, buck rubbing usually stops, or if it does occur, it does not damage the inner bark.

Examining the results of this study, taking into consideration cost, time involved, and effectiveness, the old stand-by Dial soap would be recommended. One problem we often heard was that soap does not last long on the tree. Ours is still hanging after two years. All you need to do is drill a hole and hang it with fishing line.

Everyone has his/her favorite stand-by deer repellent. We have been told to use human hair bags, sulphur/egg mixtures, large cat feces from a zoo, and even human urine. If nothing else, I hope this report will assist landowners with deer problems in their decisions if deer repellents are considered.

A special thanks to Tree World of Sechelt, British Columbia, who provided their product “Plantskydd” for free testing. Also, special thanks to Lorna Konsis and Amy Steeples for their assistance in compiling this data.