Eliminate Yellowjacket Problems
Edited article from May 2018 newsletter by Bill Holmes
The University of California Riverside researched the effectiveness of several insecticides placed in baiting stations to eradicate yellow jackets. http://www.pestboard.ca.gov/howdoi/research/2009_yellowjacket.pdf
They discovered that a small amount of fipronil (active ingredient in Frontline flea and tick topical solutions for pets) mixed with Friskies Ocean whitefish or Swanson’s® brand canned minced white chicken was very effective at reducing YJ colonies.
Fipronil is not registered for use against YJ’s, but the product that is registered, Onslaught, was not effective.
Chicken or whitefish baits consisting of 0.0025 to 0.025% fipronil were consistently the most effective baits tested.
The best results were obtained when the numbers of yellowjacket foragers exceeded 10 wasps/day/trap (Rescue Yellowjacket traps available at many stores)
You can buy fipronil in products like Taurus SC or Termidor SC, but only in quart or larger sizes and starting at something north of $40. You only need a few drops per baiting so this would be like a lifetime supply. Products like Frontline will allow you to get a smaller volume, but many have ingredients in addition to fipronil. For instance, Frontline Plus has methoprene that may deter YJ’s from visiting your bait. I purchase Sentry FiproGuard for small dogs from Chewy.com, 6 treatments for $16.51. Each vile is 0.67 ml of 9.7% fipronil.
First build a small cage using a couple of pieces of 1x6 lumber and ½” hardware cloth. The cage will keep birds and mammals out while allowing YJ’s free access. You should build in a door for easy bait replacement. Take a 5.5 ounce can of cat food and add 5 drops of fipronil and mix thoroughly. Place ¼ of the mix into a mason jar lid and set inside your cage. The remainder gets a cap and goes into the refrigerator safely and properly labeled. Remove and replace mixture daily for 4 days. Yellow jackets do not like dried out food. Also add fresh attractant to the nearby Rescue yellow jacket trap which helps attract YJ’s to the bait or squirt half the contents of a tube of RESCUE Yellowjacket Attractant onto a cotton ball and place inside the cage but not in the bait mix. Place the bait cage in the shade 4 feet off the ground and at least 10 to 15 yards away from doors, patios, grills, or people trafficked areas. Within 24 hours 80% of the Yellowjacket nests within 100 yards will be dead, 95% will be gone in 48 hours. Colonies up to 250 yards away will be significantly reduced. Yellow Jackets rarely forage more than a few hundred yards from their nest. Monitor the success of the project by keeping a Rescue Yellowjacket Trap in the yard with fresh attractant.
Fipronil is a relatively slow working insecticide which allows the foragers time to return to the nest, feed larvae, and track poison all over the place. Do not use more than recommended because you want foragers to live long enough to return to the nest and then show additional foragers where to find your bait.
Treatment should not start until July or early August. You want lots of YJ’s foragers to collect bait and return to the nest. The best time is when your Rescue traps are catching more than 10 YJ’s per day. Fipronil is toxic to bees too so don’t add sugar to the mix. It should be a meat dinner only which will not interest your honey bees.