When removing drone brood from a few production hives yesterday, I noticed that I was attracting Yellowjackets to my pickup truck bed. These insects are both very hungry and attack in VERY large numbers this time of the year. In a bad year, I have seen them systematically take down a row of 5 production strong hives, one after the other.
I have had some success using baited traps in the Spring to catch the solo overwintering Queen Yellowjackets, thereby reducing to load of individuals available to attack my yards in the Fall.
