The pheromone bait for those traps is pretty useless but the overall design isn't bad. The keys to getting them to work is filling them with either cider vinegar or apple juice, sugar and decaying insects. I had a real problem with those big, nasty European Hornets destroying my Lilac bushes last year and was having a hard time nabbing them. Once I switched to cider and sugar I found that the more dead Yellowjackets there were in the traps, the more Hornets I got. Disgusting picture here but with the right bait, they work pretty well.
I put several of them up last week and got a pretty big one. Hopefully it's a queen.
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