EAST LANSING, MI

Stanley Ries, a researcher at Michigan State University, has found that certain species of Daffodil (Narcissus/Amaryilidaceae) and Iris (Iridaceae) families contain compounds that repel deer and rabbits.

The National Landscape Association reports that in a research project partially funded by the Horticultural Research Institute, Ries found that daffodils-- selected for their repellent activity-- contain active compounds in both their foliage and bulbs. The researchers were able to isolate and identify the particular compounds present in daffodils that repel animals. They also learned that it is often more practical to extract natural products than to synthesize them, even when the chemistry is known.

Significantly, one formulation that the researchers developed has been more effective in repelling deer than four of the most available commercial products. The results are encouraging, but Ries indicates researchers still must develop an efficient method for extraction of the compounds responsible for repellent activity, as well as develop a practical method for application in the nursery environment. The key, according to Ries, will be "to come up with a formulation that is inexpensive, resistant to erosion and breakdown, and is easily applied."