Swarm Lures Compared: Lemongrass Oil, Pheromone Lures and Old Comb
An empty swarm trap is just a box. What turns it into a place scout bees want to report back about is how it smells. Swarm lures are the cheapest part of a trap and one of the biggest factors in whether it ever catches anything.
This guide focuses on the bait itself: what each lure does, how to use it without overdoing it, and how to keep it working. For trap boxes, sizing and placement in general, see our guide to setting up bait hives, and for catching swarms you can see, how to catch a swarm.
- Old brood comb is the most natural attractant: it smells like a home bees have lived in. One old dark frame in a trap is a common starting point.
- Lemongrass essential oil contains compounds similar to the scent bees use to mark a location. A few drops is enough; more is not better.
- Commercial swarm lures release attractant slowly over weeks and are the most convenient option.
- Combining old comb with one lure is a popular approach. Refresh oil regularly, and put traps out before your local swarm season starts.
Why lures work
When a colony swarms, scout bees search for a new cavity and advertise good ones to the swarm. Scouts are drawn to places that smell like other bees have lived there: old comb, wax and propolis. At a promising site, scouts expose their Nasonov gland and fan, releasing a scent that helps guide other bees in.
Swarm lures imitate those cues. They do not “pull” a swarm out of the sky. They make your trap more noticeable and more appealing to scouts who are already in the area. That is why placement and timing matter as much as the bait.
Lure options compared
| Lure | How it works | How long it lasts | Pros | Cons |
|---|---|---|---|---|
| Old brood comb | Smell of a lived-in cavity | All season if protected | Free if you have it; natural | Wax moths; risk of spreading disease from unknown comb |
| Lemongrass essential oil | Similar compounds to Nasonov pheromone | Fades within days to a couple of weeks | Cheap, widely available | Needs refreshing; too much can put scouts off |
| Commercial pheromone lure | Slow-release attractant blend | Typically weeks; check the package | Low effort, consistent | Costs more per trap |
| Propolis / wax rubbed inside | Smells like a bee cavity | Long | Free from hive scrapings | Weak on its own |
| Combination (comb + lure) | Layers several cues | Varies | Widely recommended | Slightly more setup |
Durations vary with temperature, sun and product, so check the lure’s own instructions and use your own records to judge.
Old brood comb
A frame of old, dark brood comb is the single most common bait among swarm trappers. Scouts recognise it as evidence that a colony once lived there.
- Use comb only from colonies you know were healthy. Old comb can carry disease spores, including American foulbrood. Never use comb from a colony that died of unknown causes or from an unknown source. See our American foulbrood guide.
- Protect it from wax moths. A single frame in a warm trap can be destroyed by wax moth larvae. Many trappers freeze comb before use and check traps regularly.
- One frame is usually enough. Fill the rest of the trap with frames of foundation or empty frames with starter strips so the swarm has somewhere to build.
Lemongrass essential oil
Lemongrass oil is the classic DIY lure because it shares key scent compounds with the Nasonov pheromone bees use to mark a location.
How to use it
- Buy pure lemongrass essential oil, not a blended fragrance oil. Check that the label lists lemongrass oil only.
- Use a few drops on a cotton ball, a twist of paper towel or the top bar, inside the trap near the entrance. A heavy dose can be overpowering to scouts and is a common beginner mistake.
- Contain it. A cotton ball inside a small zip bag with a few holes, or in a small vial, slows evaporation.
- Refresh regularly. In warm weather oil evaporates quickly. Many trappers re-dose every week or two through the season.
Lemongrass oil on your hands or gear can attract curious bees, including near your own hives. Handle it with gloves and keep the bottle closed and away from active colonies.
Commercial swarm lures
Commercial lures are usually small vials or packets that release an attractant blend slowly. You hang or tape one inside the trap and leave it.
The appeal is convenience and consistency. If you run several traps, or traps that are a drive away, a slow-release lure means fewer refresh trips. Check the package for how long the product is designed to last and how to store unused lures (many recommend cool, sealed storage).
Lures only work with good placement and timing
Even a perfectly baited trap will struggle in a poor spot. The general guidance most trappers follow:
- Timing: have traps up before your local swarm season. Ask your local association when swarms typically start where you live.
- Height: traps raised off the ground, often several feet up, tend to be more attractive to scouts than traps on the ground. Only climb as high as you can safely reach to take a full, heavy trap down.
- Visibility: a trap on a clear landmark such as a tree on a field edge or a fence line is easier for scouts to find.
- Size: scouts generally prefer a cavity around the volume of a single deep Langstroth box.
- Entrance: a small entrance, often near the bottom.
- Distance: traps some distance from your own apiary can catch swarms from your colonies and from wild colonies nearby.
- Permission: only put traps on land where you have the owner’s permission.
After a catch
Check traps regularly during swarm season. Steady traffic with bees carrying pollen is a good sign that a swarm has moved in.
- Wait a short while so the swarm settles and starts building, then move the trap at dusk when foragers are home.
- Close the entrance with a screen or plug and strap the box.
- Transfer to a hive, moving frames across in order.
- Monitor for mites and disease. A swarm of unknown origin may carry mites or disease. Keep it a little apart from your other colonies at first and inspect carefully.
- Re-bait the trap if there is still swarm season left.
If you would rather catch visible swarms than wait for traps, getting on your local swarm call list is a good complement.
Frequently asked questions
How much lemongrass oil should I put in a swarm trap?
A few drops is enough. Too much can be overpowering to scouts. Put it on a cotton ball or in a small container near the entrance inside the trap, and refresh it every week or two in warm weather.
Do swarm lures attract bees from my own hives?
They can draw curious foragers, and they may catch swarms from your own colonies. Keep lures sealed and away from active hives, and handle oil with gloves.
Is old comb better than lemongrass oil?
Many trappers consider old brood comb the strongest single attractant, but it carries a disease risk if its history is unknown and attracts wax moths. Combining clean old comb with a lure is a popular approach.
How long do commercial swarm lures last?
It depends on the product and conditions. Many are designed to last several weeks. Check the package instructions.
When should I put swarm traps out?
Before your local swarm season starts. Your local beekeeping association can tell you when swarms usually begin in your area.
The bottom line
For most people, the best swarm bait is a combination: one frame of old brood comb from a known healthy hive plus either a few drops of pure lemongrass oil or a commercial slow-release lure. Go light on the oil, refresh it regularly, protect comb from wax moths, and remember that a lure only helps a trap that is in the right place at the right time.
Get local help. Beekeeping is very regional. Your local beekeeping association and your state’s cooperative extension service know your climate, forage and pest pressure far better than any general guide, and many clubs run mentoring programs and equipment loans. Some states and municipalities also require hives to be registered or set rules on where they can sit, so check before you set up or move colonies.