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Colony death by yellowjacket attack

Colony death by yellowjacket is common, but I’ve never heard as many yellowjacket stories as I have this year. People describe how colonies that seemed strong a month earlier are now gone, replaced by yellowjacket scavengers. Or they describe seeing yellowjackets freely entering the hive and seizing prey, undeterred by guards. What is going on?

What is a yellowjacket?

To be clear, a yellowjacket is a type of wasp that is usually black with yellow markings, although some may have white markings. In most places other than the United States, they are referred to simply as wasps. The species that cause problems for beekeepers are social insects that maintain large nests and raise their young on chewed invertebrates. Most species build a nest in an underground cavity, although certain species known as aerial yellowjackets build nests in trees or against buildings—nests that look very much like those of bald-faced hornets. In fact, aerial yellowjackets and bald-faced hornets are closely related, both in the genus Dolichovespula.

Why do they go after my bees?

Honey bees are particularly attractive to yellowjackets because one colony can provide a large supply of prey even late in the year. As an added bonus, the honey bee hive also contains larvae (food that doesn’t fight back), pollen, and honey. An entire smorgasbord awaits the predators who get through the door. Most yellowjackets do not forage very far from their home, usually no more than 1000 feet. So if you are seeing lots of yellowjackets around your hives, you have a nest fairly close by.

Wasps are beneficial insects

For the most part, wasps are considered beneficial insects because they eat many invertebrates that harm agricultural crops, including caterpillars. In fact, yellowjackets are scavengers and often do a good job of cleaning up the dead bees around a hive. The problem, of course, is they will keep coming back for more, especially as the weather becomes colder, drier, or other insects become scarce.

The yellowjacket life cycle

The life cycle of yellowjackets is very similar to that of bumble bees. Solitary mated queens overwinter in a protected spot. Early in spring, the queens emerge and begin looking for a place to build a nest. All by themselves they build a small nest, lay eggs, and provision their young with masticated insects. After the first set of workers emerge, those workers take over the job of raising the young and provisioning the nest, and the queen becomes a stay-at-home mom, spending her days laying more eggs.

Yellowjackets are worse in the fall

Honey bee populations peak in the spring and early summer along with the supply of pollen. As dry weather sets in and pollen becomes scarce, the number of honey bees in a colony decreases. So while the honey bee populations are decreasing, the yellowjacket populations are increasing, maxing out in August or September.

For that reason, yellowjackets in spring don’t seem like much of a problem—the ratio of ‘jackets to honey bees is insignificant and there are plenty of other insects for yellowjackets to eat. But by late summer the tables have turned and the earth is overrun by hungry wasps with a hankering for tender bees with yummy honey sauce.

The weather makes a difference

I can usually predict a bad yellowjacket year by the winter weather. A very cold winter with lots of snow, ice, wind, or rain will kill many of the overwintering queens. The probability of any individual queen surviving the winter goes down as the weather gets worse. Conversely, a mild winter will ensure a good crop of spring queens.

Then, too, if the summer is mild and wet, there will be plenty of insects around for the yellowjackets to eat. But if the summer is hot and dry, plants dry up, plant-eating insects die for lack of forage, and yellowjackets search for higher-risk food items, including honey bees.

This past year in western Washington, we were set up for a bad yellowjacket year due to a mild winter followed by a harsh summer. True to form, the wasps were out in force this fall—I’ve never seen more.

Weak colonies can’t repel an attack

A strong colony can usually hold its ground against yellowjackets, repelling them at the entrance. But colonies that are weak for any reason are vulnerable. Once you see a yellowjacket saunter freely through the hive entrance, you are in trouble.

Yellowjackets will sometimes bite off the the bees’ head, tear out the larvae, kill the queen, and break open honey cells. Once the honey begins dripping out of the hive, honey bee robbers will appear, and before long the colony is beyond hope. Sometimes the remainder of the colony will leave, more often they give up and become easy-to-catch prey.

Stopping a yellowjacket attack

Stopping a yellowjacket attack is difficult at best. You can close the hive, throw a wet blanket over the top, and wait. But usually, by the time an attack is evident, irreparable damage has been done.

I once watched an attack in action at a hive I had at an outyard. The property owner called to say that my bees were grouped under the hive stand. When I got there, the colony was indeed huddled below the stand and the hive itself was teeming with yellowjackets. I killed as many as I cold for an hour or more, but the supply never lessened. They’d torn open the honey cells and the brood cells, excavated the pollen, and were carting away bee parts as fast as they could.

Lessening the number of yellowjacket colonies

I learned a lot from watching that attack, and I have been proactive with wasps since then—perhaps overly so, but it is working for me.

I start in early spring with a reusable yellowjacket trap and a butterfly net. The important thing is to catch the queens early in the year. In the beginning the queens are out and about, doing all the initial work themselves. If you can kill them at this stage, you can prevent the establishment of a colony.

The pheromone lures get some, but I get more with the net. The queens are big, noisy, and easy to net. They need to eat frequently in order to do all that work, so you will see them drinking nectar at whatever is in bloom. Remember, yellowjackets don’t travel far from home, so if you can get a few queens in spring, you will save yourself a world of woe by autumn.

After the queens settle in, I have often found early workers by the sound they make as they scrape wood fibers for nest building. I have a woodshed made of unfinished lumber, and one time while I was out getting wood I was drawn to a distinctive scritching sound. On the outside of the shed were no less than five yellowjackets scraping the fibers off the siding. Last year, in the garden I heard the same sound and found two yellowjackets scraping wood fibers from unfinished tomato ladders.

The point is, killing the earlier individuals has the most impact on colony survival. The queen, of course, is the most important. But her first batch of brood is not large, so if you can get a good percentage of those, you may forestall the colony.

By late summer and early fall, killing an individual worker doesn’t make much difference. By then, you need to focus on protecting your honey bee colonies.

Preventing a yellowjacket attack

During early spring and summer, damage to honey bee colonies by yellowjackets is minimal. Bee colonies are large, yellowjacket colonies are small, there is plenty of food, and lots of water.

During this lush period you can afford fully open main entrances, upper entrances, ventilation shims, or any number of other openings. But once a nectar dearth begins, you have to reconsider how many openings your colony can defend. A large boisterous colony will be fine, but smaller or weaker colonies will probably need to be closed down.

Here in yellowjacket country, I reduce entrances to all but my largest colonies. The medium-sized ones I reduce to 4-inch by 3/8-inch main entrance, and the small ones to 1-inch by 3/8-inch. I remove all upper entrances and shims, and replace these with screened inner covers for ventilation. Since all my colonies have screened bottom boards, I am able to maintain through-the-hive airflow.

Even though both the yellowjackets and bald-faced hornets were cruising around the hives and cleaning up dead bees, none of my hives were breached this year in spite of multiple nests in the area.

During the fall, I also keep the pheromone lures fresh. Although they don’t seem to catch as many yellowjackets as I would like, they do catch some, so I keep going with it. All the homemade traps I have made have been a miserable failure, even though I’ve tried smoked turkey, ham, tuna, cat food, apple cider vinegar and everything else I’ve read about. I’m going to give up on that and stick with the commercial variety which use heptyl butyrate as an attractant.

Gone with the freeze

In temperate areas, the workers will all be killed with the first hard freeze, with only the queens surviving the winter months. In those places we get a reprieve from their antics and a little time to think about what to do next year. However, in the warmer areas of the country, nests may survive from year to year.

I feel for all the beekeepers who described their yellowjacket experiences to me, and I hope this summary will provide you with some ideas for next year. Who knew becoming a beekeeper meant learning so much about so many different things?

Rusty
Honey Bee Suite

Yellowjacket-collecting-wood-fibers
Yellowjackets and some other wasps build their nests from well-chewed wood mixed with saliva. You can see where this one has scraped fibers from a piece of unfinished lumber in my garden. © Rusty Burlew.

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Comments

Blanche
Reply

Oh yes, THANK you. I was feeling awful because I thought I did something wrong.

The orchard hive colony, the one that had tons of food all around and should have survived has all the signs you described. It’s also the one closest to all the places where jackets nest, in the pole barn, the tractors, any damned thing we’ve got that doesn’t get moved or used or looked at in two weeks or more. That was the one where I questioned whether milkweed pollen has some protective qualities against varroa. 🙂

The one out back of the pasture, that is furthest from water and buildings of any kind, is doing amazingly well. (It’s also a swarm colony off a feral colony way the heck out of reach of anything up near top of a cottonwood in a rot hole.)

donna berti
Reply

Here in the southern area of Denver, it feels as though we are being invaded by these nasty insects. My one viable hive is in a field and the yellow jackets have been flying around the hive like crazy! (They had already destroyed one hive during the summer and it was just as you describe in your post.) I had 3 exterior feeders on the eight frame hive, which left little room to enter/exit which seemed to work pretty well. I was very careful when doing my final inspection this past week. I barely lifted the outer cover and winter quilt as I didn’t want to allow any of the yellow jackets into the hive. Lots of bees were feasting on the winter patties and I didn’t see any yellow jackets inside. This current hive is a mix of a swarm and nurse bees and larvae that I helped rescue from a tree. They are relatively small and I am keeping my fingers crossed that they make it through the winter. Our weather is still pleasant, but in our area that could change overnight. Rusty, thanks for this excellent article!

Adam Rose
Reply

I personally don’t have too much of a problem with what we call wasps in the UK. But people that do have used various kinds of “confuse the wasp” entrances to reasonably good effect.

One tactic is to put a glass screen in front of the entrance. The bees can figure out that they need to fly around the glass screen but the wasps have great difficulty.

The other is a periscope entrance. This might be easier to do with a top bar hive than any other kind of hive. It involves making a vertical tunnel so that the bees and wasps have to fly in horizontally, then fly up the tunnel, and then horizontally again to get into the hive. Apart from confusing the wasps more than the bees, this provides a long tunnel which even a relatively weak hive can fill with guard bees.

Adam.

Eddy Radar
Reply

I didn’t have noticeably more this year than normal, maybe because we did a better job with new nest removal! But I will surely watch for next year! I take it the wasp lure is just a commercial hep-buty one available in stores.

Rusty
Reply

Eddy,

Yes. If I knew where to buy just the chemical itself, I would.

WesternWilson
Reply

Here just north of you across the USA/Canada border on the coast, it has been an horrific yellowjacket year as well. Robbing screens have saved my colonies, they have been on since early July. I find the Rescue brand pheromone traps work the best, and I have tried all kinds! I will be setting them out as soon as the days warm a little in spring…March-ish.

Susan McElroy
Reply

This year in SW Washington, I’ve heard that the yellow jackets have been especially bad. I had fewer problems with them than in years past, though. In late winter, my granddaughter and I made a fake hornet nest with wallpaper paste, newspaper, and a balloon. I painted it when it was done, and my girlfriend made fake bald-faced hornets out of polymer clay to wire onto the “nest.” I hung it in my bee yard, by the hives. I had read that hornets are very territorial and will not build near other nests, and also that yellow jackets are one of the favored food of bald faced hornets and that the sight of a nest could be a deterrent. I don’t know if it had any effect, but my wasp numbers were small, and NO hornets at all, all summer. I’ll move the nest in spring to see if I have a second good year with it.

Rusty
Reply

Susan,

Now that sounds interesting. I need to commission you to build me one!

Suz
Reply

It happened to my really strong colony a week ago. 2 deeps and a medium full of honey and pollen. Full of bees that had been well fed and treated for mites. The honey bees completely disappeared. Yellow jackets were going out and put. All kinds of yellow jackets. But out of the hoards, Only 6 went into the wasp traps.

Jesslyn Howgate
Reply

Same experience. Shocked to see a healthy hive with a highly productive queen decimated by the yellow jackets. I find that the attractants that are refillable don’t continue to attract the YJ. I had better luck with the kind that you fill with water and hang. After a couple of weeks I replaced it.

Suz
Reply

It happened to my really strong colony a week ago. 2 deeps and a medium full of honey and pollen. Full of bees that had been well fed and treated for mites. The honey bees completely disappeared. Yellow jackets were going out and put. All kinds of yellow jackets. But out of the hoards, Only 6 went into the wasp traps. I had reduced the entrance in July to 2 inches

EllenW
Reply

I heard recently that you can wipe out a yellow jacket nest by covering the entrance with a clear glass bowl or vase. Put the bowl in place in late evening or early morning to avoid being stung, and make sure there is a tight seal. You can add dirt or sand around the base to seal.

The Yellow jackets do not dig under the glass, perhaps because they are confused by the fact that the sunlight is not obscured. Have you heard anything about this method?

Rusty
Reply

Hey Ellen,

No, I hadn’t heard that, but it seems to make sense. Unfortunately, my yellowjackets are the aerial type, 30 or 40 feet up a Douglas fir, otherwise I would try it.

Philippa Burgess
Reply

Hi Rusty,

This trap worked wonders for me.

http://www.paynesbeefarm.co.uk/softwood/apishield-hornet-trap/

It caught hundreds of wasps in my apiary that was under attack. It was so worth the money I’ve bought one for each of my apiaries. Sounds like you need them over there!

Philippa (UK)

Rusty
Reply

Looks interesting.

Amanda
Reply

Here in Luxembourg we had a mild winter followed by a (for us) hot and dry summer. I had a lot of problems with yellow jacks in August and September. I also had pretty good luck with homemade traps. My most effective method was to make a hole (about the size of my littlest fingertip) with a screwdriver in the lip of a glass jar. I smeared the underside of the lid with fruit jam, and then filled the jar about half full with apple juice. Lid on, and trap near the hive entrance. My bees ignored it, but it filled up quickly with wasps. I had better results with this than with a trap made from plastic bottles. I also put in my entrance reducer.

Next spring I’m going to try the papier-mâché method — I’d rather deter than kill other insects if I can. But at the end of the day I will do what I can to protect my hives.

Robbin
Reply

I have noticed this season the numbers seemed low for paper wasps, and what we call yellowjackets here in north eastern Maryland. I’ve noticed much more European or bald-faced hornets. We had a very cold snowy winter last year. I haven’t had a problem yet with attacks. But I have seen those big yellow European hornets drinking nectar from a hummingbird feeder I left up, which I’ve been reading is normal as the spring is the attack time for hornets looking for larvae. But am going to reduce my entrances today while it is rainy and cool. What we call yellowjackets are bees the size of honeybees, but quicker and more aggressive. I open feed syrup well away from my 3 hives in late summer to prevent robbing and have noticed very very few of those bees, when normally at apple season they are everywhere. But in all those thousands of honeybees, there will be one or two bald face hornets eating alongside the honeybees.

PS can’t find the hornet nests, but neighbors complain about those yellow European hornets in their trees or swarming on a bush or pole. Seemed to be worse this fall.

Robbin

christa mcfarland
Reply

I have a couple questions . I live in Harpersfield, Ohio, Ashtabula County and we are in the snow belt. I am a first time beekeeper and discovered a couple weeks back my hive had wax moths. There was not a huge infiltration of them and was able to destroy the moths. They did not infiltrate the comb. They were making homes on the wood frame itself. The hive appeared to be strong. I also have yellow jackets flying around my hive, I have killed a few of them and have seen them go into the hive but my honey bees seem to be pretty good at fighting them off. While checking my hive and discovering the wax moths I did eradicate two wasps that were setting up on the comb. Any suggestions would be greatly appreciated. Although my hive appears strong I am worried it may be weak and need suggestions on what I can do so they make it through the winter. We are going to have temps in the low 50s this week so I am going to check the hive one more time for wax moths and then I want to winterize my hive.

Christa McFarland

Steve Rodney
Reply

This is a fascinating article. Thank you.

Chris
Reply

We too have noticed a larger than normal population of yellow jackets in St. Louis MO this year. We’ve found them around the hives, in the top of feeders, even in parks where the kids play. Wonder why this year there was so many more than usual.

Scott B
Reply

This was my 1st year with a hive. It was a great experience right up to the point where yellow jackets destroyed the hive. I followed all the guidance about protecting the hive (reducing the entrance, putting out wasp traps, etc) but it didn’t seem to matter. The YJ’s overwhelmed the hive. What do you do when the hive is destroyed and the YJ’s are carting off all of the honey? Do you let them clean out the hive or do you dismantle the hive (depriving them of the honey)?

Rusty
Reply

Scott,

I would definitely try to save the honey. That honey is the very best thing for getting your next colony off to a quick start.

Susan McElroy
Reply

If there are honey stores, I take them. To hell with the YJs!

Alex
Reply

Rusty,
Love the blog. I’m headed into my first winter with one hive. My colony is fairly small right now (they were a swarm I caught in late spring). They don’t even fill a full box (maybe 3/4 full). I am pretty concerned about the cluster being big enough to survive a cold winter, and so I am planning on moving them to my parents house in the much warmer southwest when I go home for Thanksgiving. My question is this: how well would bees handle being locked up inside their hive for? I am tempted to close all the entrances and move them into a warmer spot indoors (garage, etc.), but not a place they should be exploring. Would they stay put for two weeks locked in their hive, but warm? Or would it stress them out?
Thanks
Alex.

Rusty
Reply

Alex,

Bees spend the entire winter inside their hive, sometimes it is many weeks or multiple months before they get out. Also, bees are trucked all over the country for pollination services, so two weeks should certainly be no problem. As long as they have ample food they will be fine. They need fresh air though, so used screen over the entrances.

Janet
Reply

Although I am not a beekeeper I have been feeding the wild bees since August until late last month. Now that its cold, they have gone back to their hives, (I assume).

During the time I was feeding, there were yellow jackets that also ate alongside the honey bees, but there didn’t seem to be any problems. Sometimes I would see honey bees attack a weaker honey bee? At least that’s what it looked like.

In the fall I noticed there were more yellow jackets. I had about 5 or 6 dishes with sugar water as there were so many and it was non-stop feeding. I did notice that the yellow jackets congregated together (although some did sip the sugar water with the honey bees). Is that unusual? I really didnt realize that the yellow jackets did harm to the bees 🙁

Rusty
Reply

Janet,

There is no reason for bee/yellowjacket fights when they are away from the hive. Bees away from the hive are not protecting anything. It’s the home invasion that riles things up. Think about this: If you sit next to a stranger in a restaurant, it is no big deal because you both went there to eat. If that same stranger barges through your front door uninvited and starts cleaning out your pantry and attacking your children, you might feel differently about it.

Jerry Holman
Reply

Rusty, thanks.

This year was my first year and I thought I was doing ok. I really thought I had a pretty good hive till I started feeding the bees this fall. Even though I had the feed inside the hive no matter what I did the yellowjackets got in. I had reduced the entrance and It appeared my bees were willing the battle. Then one day I open the hive because I did not see any of my bees coming or going or even defending. When I opened the hive all I had were yellowjackets and dead bees. Queen and all the store of honey were gone, the young brood dead and a new queen that was ready to come out of her cell dead. I guess All I can do is wait till spring. I had two traps I made that were full of yellowjackets that I had emptied at least five times, but that was still not enough! Hope spring comes early.

Rusty
Reply

Jerry,

That is so, so sad. But you are not alone.

Ken
Reply

Hi Rusty

Not sure I’m looking for any answers, but your opinion is valued. I live in Northern Colorado. Temperatures at night have been in the upper teens to mid twenties and day upper twenties to lower fifties.

When would you expect yellowjackets to stop attempting to raid the hives? From what I’ve observed and read, yellowjackets can and do fly at lower temperatures (35F) than honey bees (50F in full sun). So YJ can and do enter the hive unchallenged at the lower temperature. I am wondering what kind of damage the YJ can do while no HB is on guard duty.
Thank You
Ken

Rusty
Reply

Ken,

Most wasp nests, including yellowjacket nests, are wiped out after the first hard freeze. Yours should be dead by now, but perhaps their nest is in a sheltered area that’s getting heat from somewhere . . . maybe in a barn or garage. In any case, yellowjackets entering a honey bee hive unchallenged can kill it very quickly. They will eat adults, brood, and honey.

Paul
Reply

Feed them openly and try to follow them home. They’ll go back to the nest after they’ve picked up food. Then kill the nest. I used to exterminate them and didn’t have the safety net of a bee suit. Don’t really need one anyhow. Just find the nest (hope it’s not in a perilous location) wait until dark and set a very bright light off from your location directed at the nest. If you mess up they will attack the light. Also, use a distillate based pesticide in a wand sprayer so they can’t communicate attack pheromones and stick it right up the hole and blast em good. They won’t know what hit them. I’ve killed so many of these things I almost have a guilty conscience. If they’re hurting your bees or family, it’s a declaration of macheveilin warfare. For trapping or baits, I used to swear by orange crush, sometimes nothing seems to really work well. I know everybody and they’re dog swears something works better than anything. I know if you cook a nice steak on the bbq every wasp for miles shows up and wants some of your steak but I usually don’t feel like sharing but you could forgo a portion of dinner and work up an extra appetite hurtling over your neighbors fence tracking Yellowjackets back home… If that sounds fun.

Cathy
Reply

I was reading about the yellowjackets. We have 3 sugar water feeders and the yellowjackets are becoming more in number. If they just drank the water, I might leave them be but I know what they are capable of. How can I keep them away from the sugar water? I found a DIY Yellow Jacket Bottle Trap using red wine and isn’t suppose to lure the honeybees.

Rusty
Reply

Cathy,

This is one of the negative aspects of open feeding: everyone is invited. You could try a homemade yellowjacket trap. Any kind of meat also works well in a trap, and bees, unlike wasps, are not interested in meat.

Cathy
Reply

Please pardon my ignorance but how do you make the yellow jacket trap you mentioned. I read about one with red wine and dishwashing soap but they are still in the feeder. We think that 4 houses up is where the nest is…..it would be about the 1000 ft. theory from the nest.

Rusty
Reply

Cathy,

I would just look for several different ideas on the web and try one. I use the commercial ones made by Rescue!

Cathy
Reply

I was halfway to Lowe’s yesterday and picked up several. I hung my first one this morning. We do know where the nest is located just trying to get up with our neighbor to assisting him if necessary to get the nest.

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