Repellents

Repellents are most effective when integrated into a damage-control program that includes fencing, hunting, and several types of repellents. Apply repellents at the first sign of damage to prevent deer from establishing a feeding pattern at the site. Area repellents include tankage (putrefied meat scraps), ammonium soaps, bone tar oil, blood meal, and human hair. Contact repellents work by taste and must be applied directly to the plant. These repellents work best if you apply them in the dormant season on dry days when temperatures are above freezing. Examples of contact repellents are putrescent egg solids, thiram, and hot pepper sauce (capsaicin). Remember that whenever you apply a commercial repellent, you are required by law to comply strictly with the label. Home remedies often have limited success.

Human hair can be obtained from a local barber shop and placed in small bags (cloth or plastic--if plastic is used, punch three to four holes in the bottom). Tie up the tops and hang them around the garden or individually in trees. Soap bars can be placed in individual trees. Blood meal and tankage can be hung around the perimeter of the planting, initially 20 feet apart and then closer together if needed. Place these items about 30 inches off the ground, about the average height of a deer. Remember, success depends upon early preventative monitoring, as well as on alternation of materials.

Repellents containing denatonium saccharide, such as Ro-Pel, have been found to be less effective. There is little evidence to suggest that the bittering agent, denatonium saccharide, works as a mammal repellent. These products are taste repellents that may only be applied to plants during the dormant season. Because they are taste repellents, the new growth in the spring is not protected. Denatonium saccharide, including Ro-Pel, is not approved for rabbits. However, it is an approved deer repellent.

Repellents have variable results--what works for one grower might not work for another, and success differs from year to year. Some repellents do not weather well and require repeated applications during the season. Also, if deer are very hungry and the area lacks other more palatable food resources, they might ignore the repellents. Success must be measured by how much the damage has been reduced since it is rarely eliminated. In areas where deer density is low and damage is light, repellents may be a cost-effective part of your IPM strategy.