What's the Most Effective Way to Repel Yellowjackets During Barbecues?

Sanitation first: keep food and sweet drinks covered, use lidded cups instead of open cans where possible since wasps have been known to crawl inside cans and sting the inside of the mouth or lips, and clean up food scraps promptly rather than letting them sit. Barrier covers second: mesh food tents and lidded containers remove the cue entirely rather than trying to out-compete it. Distant traps third: placed well away from the gathering, not on or near the table, since a nearby trap can draw more foragers toward people instead of fewer.

Concentrated essential-oil sprays do have real, peer-reviewed short-range repellency — see our page on essential oils — and they're a legitimate minor addition to the routine above. But extension sources treat removing the food cue as the highest-leverage move for a barbecue specifically, since late-summer yellowjackets are actively scavenging for sugar and protein and will keep returning to an uncovered source regardless of scent deterrents nearby. In southern New Hampshire that scavenging peaks in the August-through-September stretch, when colonies are at their largest and natural food is dwindling but the first hard freeze — around October 19 in Manchester by National Weather Service climate normals — hasn't yet ended the season; those are the cookouts where sanitation matters most.

A study cited by Oregon State University Extension reduced yellowjacket presence at a picnic pavilion by ringing it with roughly 50 traps placed about 200 feet out — the traps worked by intercepting foragers before they reached the gathering, not by sitting near the food. A trap placed close to the table does the opposite: it can pull in additional wasps that then have to pass right by the people it's meant to protect.