If you are having deer issues, I know you want to learn all you can about how to control these determined landscape eaters. Let's look at how deer repellents work and the most popular brands of deer repellent.

From a USDA report:

Deer repellents generally rely on fear, conditioned avoidance, pain, or taste. Fear-inducing repellents contain compounds that emit sulfurous odors (such as predator urine, meat proteins, or garlic). We interpret the avoidance of these odors as a fear response, suggesting herbivores perceive sulfurous odors as indicators of predator activity. Conditioned avoidance occurs when
ingestion of a food is paired with nausea or gastrointestinal distress. Animals generally don’t eat as much of a food if it is associated with illness. Active ingredients, such as capsaicin, allyl isothiocyanate, and ammonia, cause pain or irritation when they contact trigeminal receptors in the mucous membranes of the mouth, eyes, nose, and gut. An inherent problem of using
pain repellents is that they are universally aversive to all mammals. Bad taste can also induce avoidance. Bittering agents are often used to induce a bad taste. Unfortunately, while omnivores normally avoid bitter tastes, herbivores are generally indifferent, at least at the concentrations
used in most repellents.

What is the best deer deterrent on the market?

Top 6 Deer Repellents

  • Best Scent: Deer Out Concentrate Deer Repellent.
  • Longest Lasting: Bobbex Concentrated Deer Repellent.
  • Best Sprinkler: Orbit Motion-Activated Sprinkler.
  • Best For Nighttime: Nite Guard Predator Control Light.
  • Most Versatile: ZOVENCHI Ultrasonic Animal Repellent.