The Bee Bench › BeeVet
Tick what you're seeing (in the brood, on the bees, at the entrance) and BeeVet lines up the likely causes for the time of year, from “that's normal” to “call the inspector,” then tells you the one check that would settle it. 95 conditions, each with what to do.
Open a section and tick everything you noticed, in as many sections as you need. The likely causes line up underneath as you go, weighted for the month, with the one check that would best settle it. Nothing is saved.
Tick what you see above and the likely causes show up here, most likely first, each with what else to look for.
The swarm has left
Most common: May to June
What you see: Thousands of bees pouring out of the hive and swirling in the air, then settling in a cluster on a branch, fence or post nearby.
What's going on: Half or more of the bees leave with the old queen to find a new home. Scouts pick the spot while the cluster waits, from minutes to a day or two. Swarms are usually gentle because they have no home to defend.
What to do: Catch it into a box with some old comb if you can reach it safely, or call a local beekeeper. Then check the hive it came from: it will be raising a new queen.
Easy to mistake for: Absconding, Orientation flights, Bearding and fanning
The whole colony leaves
Most common: May to June and September to October
What you see: Almost all the bees and the queen gone, leaving brood, pollen and honey behind and no queen cells. Most often in fall, or with a new swarm or package soon after hiving.
What's going on: Unlike swarming, absconding is the colony giving up on the home: heavy mites or disease, strong chemical smells, ants or hive beetles, too much disturbance, or starvation.
What to do: Treat the cause before re-using the hive. Give new swarms and packages a frame of brood to anchor them.
Easy to mistake for: Swarm preparation, Bees vanished, food left behind
Hybrid bee from South America
What you see: Extreme, repeated stinging: huge numbers of bees boiling out at the slightest disturbance and chasing people and animals a long way.
What's going on: Established in the southern and southwestern states, not in Pennsylvania. Our winters are too cold for them to settle. A hot colony here almost always has another cause.
What to do: Work through the usual reasons for a hot colony and requeen. If you got bees from the deep South and they're extreme, tell the state apiarist.
Easy to mistake for: Hot (defensive) colony
Bacteria: Paenibacillus larvae (spore-forming)
What you see: Spotty brood with sunken, dark, greasy cappings, some pierced. Under them, larvae gone coffee-brown that string out 2 cm or more on a stick, then dry to a black scale stuck flat to the lower cell wall. Sometimes a dried tongue sticks up from the scale. A foul, old-glue smell.
What's going on: The worst brood disease. The bacterium infects larvae in their first day or two and kills them after capping. Its spores survive decades in comb and honey. Adults carry it without getting sick, and robbing and swapped frames spread it to other hives.
What to do: Close the hive, move nothing out of it, and reduce the entrance so nothing robs it. Confirm with a field test kit or a free sample to the USDA Bee Research Lab in Beltsville, and call the Pennsylvania state apiarist. Confirmed hives are usually burned. Antibiotics only hide AFB and need a vet's order.
Easy to mistake for: European foulbrood (EFB), Parasitic mite syndrome (PMS), Sacbrood
Ants
Most common: May to September
What you see: Ants nesting in the lid, the walls or under the hive (often with white eggs and pupae), or trailing in to steal honey and scavenge dead bees.
What's going on: Ants living in the lid are mostly a nuisance. A big raid on a weak colony is the real risk.
What to do: Brush them out and put the hive on a stand. Greased or oiled legs or moats keep them from climbing up. Keep the colony strong enough to fill its space.
Easy to mistake for: Flies and maggots
Wax moth larvae tunnelling under the cappings
Most common: June to September
What you see: A straight or wandering row of uncapped cells with healthy, purple-eyed pupae showing, following a moth tunnel. Silk threads under a magnifier.
What's going on: A wax moth caterpillar ran along under the cappings and the bees pulled the damaged cappings off. The pupae usually survive.
What to do: Usually minor. A strong colony cleans it up.
Easy to mistake for: Hygienic bees at work, Parasitic mite syndrome (PMS), Wax moth
See it drawn in the Frame Guide →Brood Disease ID: bald brood →
Nothing wrong
Most common: June to August
What you see: Hundreds of bees hanging on the front of the hive or under the bottom board on a hot day or warm, humid evening, and rows of bees fanning at the entrance. They go back in when it cools off.
What's going on: A strong colony cooling the hive: moving bees outside and pushing air through.
What to do: Nothing. Water nearby and an upper vent help in a heat wave. A beard is not a swarm about to leave.
Easy to mistake for: Heat stress, Swarm preparation
Black bear
Most common: April to May and September to October
What you see: Hives smashed and scattered, boxes knocked over, frames carried off, brood eaten. Paw prints, claw marks, sometimes scat.
What's going on: Bears go after the brood more than the honey and come back night after night, usually in spring and fall, until the yard is gone.
What to do: A baited electric fence is the only reliable fix, and it's best up before a bear finds the yard. Call the Pennsylvania Game Commission about a nuisance bear.
Easy to mistake for: Vandalism or theft, Toppled hive
Nothing wrong
What you see: Cells packed with pollen in yellow, orange, red, grey or other colors, usually in a band between the brood and the honey. Some cells have a shiny honey glaze on top.
What's going on: Stored pollen mixed with nectar and enzymes. It's the colony's protein, and it's what nurse bees eat to feed the brood.
What to do: Nothing. One to two frames of it per brood box is about right.
Easy to mistake for: Entombed pollen, Pollen-bound brood nest
Wingless fly: Braula
What you see: Tiny reddish-brown specks riding on the queen. They have six legs (varroa has eight). Their maggots leave fine tunnels under honey cappings.
What's going on: A wingless fly that steals food from bees' mouths. Harmless, and nearly gone from the US since mite treatments became routine.
What to do: Nothing needed. The only harm is cosmetic tunnels in comb honey.
Easy to mistake for: Varroa mites, Wax moth
What used to be called colony collapse disorder
Most common: September to November
What you see: A colony that was fine and then, within a few weeks, has a queen, a handful of young bees, plenty of honey and pollen, and capped brood, but almost no adults and no dead pile.
What's going on: Named colony collapse disorder in 2007. Today the same picture is mostly blamed on high varroa and virus loads (PMS), with Nosema ceranae and pesticides as other suspects.
What to do: Do a mite wash on the rest of the yard right away. If you still have bees, test for nosema. Close up the dead hive so it isn't robbed.
Easy to mistake for: Parasitic mite syndrome (PMS), Nosema ceranae, Absconding, Starvation
Scarab and other beetles
What you see: Large beetles, much bigger than a small hive beetle, in the debris on the bottom board.
What's going on: Native scavengers eating debris. Harmless. (The African large hive beetle isn't in North America.)
What to do: Nothing. Clean the bottom board.
Easy to mistake for: Small hive beetle
Virus
Most common: April to June
What you see: A capped queen cell with the developing queen dead inside: yellowish and sac-like at first, then dark brown to black, with the cell walls darkened.
What's going on: A common virus that kills queen larvae and pupae after capping. It often goes along with nosema and is worst in spring. Queen breeders see it most.
What to do: Nothing to treat. Cull the dead cells. If you raise queens, keep cell builders strong, well fed and low on nosema.
Easy to mistake for: Sacbrood
Queen in the honey super
Most common: May to August
What you see: Eggs or brood in a honey super above a queen excluder, and sometimes dead drones trapped at the excluder.
What's going on: The queen got moved above the excluder during an inspection or slipped through a gap. Scattered eggs in multiples point to laying workers instead.
What to do: Find the queen and put her below the excluder. Check the excluder for damage. Give trapped drones an exit.
Easy to mistake for: Laying workers
Normal colony response to stress
Most common: March to May and September to October
What you see: Capped cells opened and pupae partly eaten or removed. Fewer young larvae than you'd expect for the eggs and capped brood present.
What's going on: Bees eat brood to recover protein when pollen stops coming in (a cold, wet spring is the usual time), when brood is diseased, and when they're removing mite-infested pupae. Drone brood gets eaten heavily in fall.
What to do: Look for the cause: check stores and pollen, feed protein in a dearth, and do a mite wash.
Easy to mistake for: Starved brood, Hygienic bees at work, Parasitic mite syndrome (PMS)
Management
What you see: Comb built between boxes, on top bars, under the lid, in feeders or in any gap bigger than a bee space, or combs built crosswise across frames.
What's going on: Bees fill any gap over about 3/8 inch with comb. A missing frame or a feeder left in is the usual cause.
What to do: Scrape it off and fill the box with the right number of frames. A strong flow is a good time to let them draw new foundation instead.
Fungus: Ascosphaera apis
Most common: April to June
What you see: Larvae turned to hard, chalky mummies, fluffy white at first, then mottled grey to black as the fungus fruits. They rattle in the cells and get dumped on the bottom board and at the entrance. No rope, no smell.
What's going on: A fungus that takes hold when brood gets chilled or stressed, usually in cool, damp spring weather with too few bees covering the brood. Some bee lines are more prone to it.
What to do: A stress sign more than a disease problem. Improve ventilation, tip the hive slightly forward so it drains, give it sun, keep the colony strong, and requeen with hygienic stock if it keeps coming back.
Easy to mistake for: Stonebrood, Chilled brood
See it drawn in the Frame Guide →Brood Disease ID: chalkbrood →
Not a disease: too few bees to keep brood warm
Most common: March to May and October
What you see: A patch of dead brood of every age, grey to black, usually at the edge of the brood nest or on outer frames, with healthy brood right next to it. Follows a cold snap, a split made too small, a long cold-weather inspection, or a sudden loss of bees.
What's going on: The cluster pulled in and left the outer brood uncovered. It doesn't spread.
What to do: Nothing to treat. Keep splits big enough, keep cold-weather inspections short, and let the bees clean it out. If the bees disappeared first, find out why (pesticides, swarming, mites).
Easy to mistake for: Chalkbrood, Pesticide poisoning, Parasitic mite syndrome (PMS), American foulbrood (AFB)
See it drawn in the Frame Guide →Brood Disease ID: chilled brood →
Normal aging
What you see: Comb that started white or pale yellow and turned brown, then nearly black.
What's going on: Every round of brood leaves cocoons behind, and bees walking on it and storing pollen darken it. Old cells get a little smaller each time.
What to do: Nothing urgent. Swap out the two oldest frames per box each year so no comb gets more than about five years old.
Post-mortem
Most common: January to April
What you see: A hive that didn't make it, usually found in late winter or spring.
What's going on: Most deadouts here trace to varroa and the viruses it spreads, often with the colony too small going into winter. Starvation and moisture are the other common ones.
What to do: Look before you clean up. White mite droppings in cells, a small cluster and honey left over: mites. Bees head-first in cells and no honey touching the cluster: starvation. Wet and moldy: moisture. If any dead brood ropes, test for AFB before reusing anything. Close it up so nothing robs it out.
Easy to mistake for: Starvation, Parasitic mite syndrome (PMS), Too much moisture, Bees vanished, food left behind
Queen lost
What you see: A dead queen (or a queen pupa) on the bottom board or at the entrance, or a queen with a damaged leg or wing.
What's going on: Usually the losing queen after a supersedure or virgin fight, a surplus virgin, or an old queen that didn't make it out with a swarm. Sometimes she gets rolled or crushed during an inspection.
What to do: Check for eggs and queen cells. Make sure the colony has a laying queen again within two to three weeks.
Easy to mistake for: Queenless colony, Queen balled or rejected
Nothing blooming
Most common: July to August
What you see: Little flying, cranky bees, robbing attempts, the queen easing off laying, and colonies that stop growing. In south-central PA it usually sets in during July.
What's going on: Nothing worth working is in bloom, from drought, heat, too much rain, or just the gap between flows. Too many hives in one spot makes it worse.
What to do: Reduce entrances, inspect quickly or not at all, and don't spill syrup or leave honey out. Feed light colonies inside the hive. Put out water if it's hot and dry.
Easy to mistake for: Robbing, Hot (defensive) colony, Nutritional stress
Virus spread by varroa
Most common: August to November
What you see: Young bees with crumpled, stubby or twisted wings they can't fly on, sometimes with bloated abdomens. Some may have cloudy wings. The brood looks normal; the damage shows only when they emerge.
What's going on: The most common and harmful bee virus, carried and multiplied by varroa. Once you see deformed wings, the mite load is already high.
What to do: Treat the mites. The virus rides in with them. Do a mite wash to see how bad it is. A lot of deformed wings in late summer warns that the colony may not make it through winter.
Easy to mistake for: Parasitic mite syndrome (PMS), Tracheal mites
Bees moving between hives by mistake
What you see: Over a season, hives at the ends of a row and in the front row get stronger while the ones in the middle fall behind.
What's going on: Bees (drones most of all) come home to the wrong hive when hives look alike and sit close together. It spreads mites and disease too.
What to do: Face hives different ways, paint them different colors, add landmarks, and avoid long straight rows.
Easy to mistake for: Orientation flights
Queen out of sperm
What you see: Raised bullet cappings scattered through worker-sized cells across the frame, with single, neatly centered eggs. Small drones.
What's going on: A queen is laying, but she's out of sperm (or never mated properly) and can only make drones. The neat single eggs set her apart from laying workers.
What to do: A drone-laying queen won't recover. Replace her, ideally with open brood in the hive so they'll accept a new queen or raise their own.
Easy to mistake for: Laying workers, Normal drone brood
Too few adult bees
What you see: Not enough bees to cover the brood. Bees disappearing faster than new ones emerge.
What's going on: Many causes: mites and viruses, Nosema ceranae, pesticides, a failing queen, a recent swarm, or starvation. In early spring a short dip is normal as winter bees die off.
What to do: Work through the usual suspects: mite wash, look for eggs and a good pattern, check stores, think about recent spraying. Combine it with another colony if it's too small to recover.
Easy to mistake for: Parasitic mite syndrome (PMS), Nosema ceranae, Pesticide poisoning, Failing or poorly mated queen, Swarm preparation
A sign more than a disease
Most common: January to April
What you see: Brown or yellow streaks and spots on the front of the hive, the lid, top bars and frames inside. A few spots on the snow after a winter cleansing flight is normal. Heavy streaking inside the hive is not.
What's going on: Bees that can't hold their waste, from long winter confinement, stores with too much water or junk in them (fermented syrup, honeydew), or Nosema apis. Damp, poorly ventilated hives get it worst.
What to do: Give them dry, clean stores and good ventilation and replace badly soiled comb. If it keeps happening, a nosema spore count tells you whether N. apis is behind it.
Easy to mistake for: Nosema apis, Too much moisture
Colony suddenly lost its queen
What you see: Several queen cells built out of ordinary worker cells right in the brood, on several frames, often mid-frame. No eggs.
What's going on: The queen died or was lost (or removed), and the bees are turning young worker larvae into queens.
What to do: Leave the best cells. If the cells are poor or it's late in the season, you can add a mated queen instead. Check for a laying queen about four weeks later.
Easy to mistake for: Swarm preparation, Supersedure, Queenless colony
Nothing wrong
What you see: Small, empty, cup-shaped wax cells hanging opening-down on the edges and faces of comb.
What's going on: Most colonies keep a few ready. They only matter once the queen puts an egg in them.
What to do: Nothing. Check for eggs or larvae in them. Many cups with eggs along the bottom edges in spring is swarm prep.
Easy to mistake for: Swarm preparation
Possible pesticide sign
What you see: Pollen cells sealed over with a dark wax or propolis cap set below the cell rim, scattered among normal open pollen cells.
What's going on: Bees seal off pollen they've sensed is contaminated, often with pesticides.
What to do: Cull frames with a lot of it. Think about what's been sprayed nearby.
Easy to mistake for: Bee bread, Pesticide poisoning
Bacteria: Melissococcus plutonius
Most common: April to June
What you see: Larvae twisted like a corkscrew, melted or slumped up the side of open cells, turning yellow, then brown. Sticky, but they rope 1.5 cm at most and the scale comes out easily. Often a sour, vinegary smell.
What's going on: A stress disease of spring, when there aren't enough nurse bees or enough food coming in. It doesn't form spores, and it often clears up once a nectar flow starts. The reason it matters is that it has to be told apart from AFB.
What to do: Help the colony: feed, cage the queen or requeen for a brood break, and swap out old dark comb. Shake the bees onto new comb if it's bad. Send a sample if you can't rule out AFB. Do a mite wash too, because PMS looks almost the same.
Easy to mistake for: American foulbrood (AFB), Parasitic mite syndrome (PMS), Sacbrood, Chalkbrood
Queen problem
What you see: Less brood than the season calls for, a spotty pattern with every age jumbled together, nectar in the brood nest, and maybe supersedure cells. The queen may look dark, worn and slow.
What's going on: An old queen running out of sperm, a queen that mated poorly, or one damaged in shipping or by heat.
What to do: Rule out mites and disease, since they cause a spotty pattern too. If the bees are building supersedure cells, let them. Otherwise requeen.
Easy to mistake for: Drone-laying queen, Supersedure, Parasitic mite syndrome (PMS), Nosema ceranae
Nothing wrong
Most common: September to November
What you see: In fall, workers dragging drones out the entrance and drones dying out front, sometimes with drone brood thrown out too.
What's going on: Drones are no use in winter, so the colony stops feeding them and throws them out.
What to do: Nothing. A colony that keeps its drones late into fall may be queenless or have a failing queen.
Easy to mistake for: Pesticide poisoning, Robbing, Queenless colony
Stores condition
Most common: July to September
What you see: Thin honey running out of the cells, foam or bubbles, and a sour or yeasty smell.
What's going on: Honey with too much water ferments. In a hive that usually means a weak colony or small hive beetles. After harvest it means supers pulled before they were capped.
What to do: Check for hive beetles. Only harvest capped frames, extract promptly, and check moisture with a refractometer.
Easy to mistake for: Small hive beetle
Nothing wrong
Most common: April to July
What you see: Bees hanging in loose chains and curtains between frames, legs linked.
What's going on: Seen when bees are making wax and building comb.
What to do: Nothing. It usually means a flow is on and they're building.
Scavengers
What you see: Maggots (soft and legless) in hive debris or dead bees, and flies around a deadout, feeders or fermenting honey.
What's going on: Scavengers that clean up dead bees and brood. A sign something died, not the cause of it.
What to do: Clean out the debris and find out what died. Beetle larvae and wax moth caterpillars have legs; fly maggots don't.
Easy to mistake for: Small hive beetle, Wax moth
Nothing wrong
What you see: Two bees face to face with their tongues out and touching.
What's going on: Bees passing nectar and food, and with it the colony's scent and queen pheromone.
What to do: Nothing.
Easy to mistake for: The queen's court
Nothing wrong
Most common: August to October
What you see: A strong sweaty-sock or wet-gym-bag smell coming off the hive from late August into October, with healthy-looking brood.
What's going on: Ripening goldenrod nectar. It fades once the honey is cured. New beekeepers often mistake it for foulbrood.
What to do: Nothing. If the smell comes from the brood itself and larvae are discolored or cappings sunken, check for foulbrood.
Easy to mistake for: American foulbrood (AFB), European foulbrood (EFB)
Nothing wrong
What you see: Bees cleaning themselves or each other, sometimes several bees working over one.
What's going on: Keeping clean, and some lines bite mites off each other.
What to do: Nothing.
Easy to mistake for: The queen's court
Weather
Most common: June to August
What you see: Heavy bearding and fanning through a long hot spell, and a colony that stops growing. Comb can sag or melt in a hive in full sun.
What's going on: Bees can cool a hive by fanning air over water droplets, but only if they have water and room. Long heat wears them down.
What to do: Give them water nearby, some afternoon shade, and an upper vent or a propped lid in extreme heat.
Easy to mistake for: Bearding and fanning
Management
Most common: May to June
What you see: Nectar and honey filling the cells in the middle of the brood frames, with the queen squeezed onto a shrinking patch.
What's going on: In a strong flow the bees fill the brood nest faster than the queen can lay in it. In spring it's a big swarm trigger.
What to do: Add supers before they need them. Move a couple of honey frames out and put drawn comb or foundation into the brood nest, or make a split.
Easy to mistake for: Swarm preparation, Queenless colony, Failing or poorly mated queen
Temper
Most common: July to September
What you see: Many bees coming out to sting when you open up, bees following you away from the yard, or bees stinging when someone just walks past.
What's going on: Something is usually behind it: no queen, a dearth, robbing pressure, night visits from a skunk, bad weather, the wrong time of day, or rough handling. Some bee lines are just hotter.
What to do: Rule out the causes first. If it stays hot week after week with none of them, requeen with gentler stock.
Easy to mistake for: Skunks, raccoons and opossums, Queenless colony, Dearth, Smoker trouble, Africanized honey bees
Good behavior: bees removing sick or mite-infested brood
Most common: August to October
What you see: Capped pupae uncapped and pulled out here and there, leaving a spottier pattern, often in late summer and fall. Mites on the sticky board may be missing legs.
What's going on: Hygienic bees sniff out brood with reproducing mites or disease in it and remove it. This is a trait breeders select for.
What to do: Nothing. If the pattern is very spotty, do a mite wash: lots of hygienic uncapping can mean lots of mites to find.
Easy to mistake for: Parasitic mite syndrome (PMS), Brood being eaten, Bald brood
Hopelessly queenless colony
What you see: Several eggs jammed into a cell, eggs on the cell walls instead of the bottom, drone cappings scattered through worker cells, and no clear pattern. A loud, roaring colony.
What's going on: With no queen and no young larvae for weeks, some workers' ovaries switch on. They can only lay unfertilized eggs, so every one becomes a drone.
What to do: A laying-worker colony will kill a new caged queen almost every time. Give a frame of open brood each week until they build queen cells, or combine it with a strong queenright colony.
Easy to mistake for: Drone-laying queen, New queen laying doubles, Failing or poorly mated queen
Field mice
Most common: October to April
What you see: A nest of grass and leaves in a lower corner, chewed comb and frames, droppings and a urine smell, and chewed bits at the entrance. Usually found in late winter or spring.
What's going on: Mice move in during fall for warmth, nest at the edge of the cluster, and eat honey, pollen and dead bees.
What to do: Mouse guard or a reduced entrance on by October, after checking there isn't already a mouse inside. Clean out the nest and replace fouled comb in spring.
Easy to mistake for: Shrews
Follows death, doesn't cause it
Most common: February to April
What you see: White to grey fuzz on dead bees and on comb and stored pollen outside the cluster, usually in a deadout or on frames the bees can't cover.
What's going on: Mold grows where bees aren't. It's a result of a colony dying or shrinking, not the cause.
What to do: Find what killed the colony. Moldy comb can go to a strong colony to clean up. Cull frames that are old and dark.
Easy to mistake for: Too much moisture, Dead colony: what killed it?
Nothing wrong
Most common: May to July
What you see: A small patch of eggs in freshly polished cells, a few with two eggs, but every egg sitting in the bottom center of the cell.
What's going on: A young queen sometimes doubles up in her first days of laying. A laying worker's abdomen is too short to reach the bottom, so her eggs land on the walls.
What to do: Wait a week or two. You should see one egg per cell and a spreading pattern.
Easy to mistake for: Laying workers
Nothing wrong
What you see: Worker brood cappings are tan to brown, slightly domed and six-sided because the bees recycle old wax for them. Honey cappings are new white wax. A few cells caught mid-capping have a round hole in the center. Drone cappings stand up like bullets.
What's going on: Healthy brood looks like this. A clean pinhole in a flat, normal-colored capping is just capping in progress.
What to do: Nothing. Worry if cappings are sunken, dark and greasy as well as pierced. That points to AFB.
Easy to mistake for: American foulbrood (AFB), Normal drone brood
Nothing wrong
Most common: April to July
What you see: Patches of bigger cells with tall, domed cappings, mostly at the bottoms and edges of frames, with normal flat worker brood across the middle.
What's going on: Colonies raise drones in spring and summer. About 5% of the population at peak is normal.
What to do: Nothing. It's only a problem when domed cappings are scattered through worker-sized cells across the frame. That's a drone-laying queen or laying workers.
Easy to mistake for: Drone-laying queen, Laying workers
Nothing wrong
What you see: Heavy traffic in and out, pollen on legs, and loaded bees landing short in the grass or on the hive wall before walking in.
What's going on: Foragers bringing in nectar, pollen, water and propolis. Heavy loads make for clumsy landings.
What to do: Nothing. It's a good sign.
Easy to mistake for: Orientation flights
Gut parasite: Nosema (Vairimorpha) apis
Most common: February to April
What you see: Dysentery: brown streaks on the frames, the hive front and the lid, worst in late winter and early spring after a long confinement. Crawling bees that can't fly, swollen abdomens, and a cluster that shrinks fast coming out of winter.
What's going on: The only nosema that causes dysentery. But dysentery on its own isn't proof, since cold confinement and poor or fermented stores cause it too. A spore count under a microscope confirms it.
What to do: Swap out the soiled comb, keep the hive dry and ventilated, and give them clean stores. Get a spore count if it keeps happening.
Easy to mistake for: Dysentery, Nosema ceranae, Tracheal mites
See it drawn in the Frame Guide →Disease & Pest ID: nosema →
Gut parasite: Nosema (Vairimorpha) ceranae
What you see: Usually NO dysentery, and that's the trap. A colony that slowly dwindles for no clear reason, any time of year: foragers die away from the hive, so there are fewer bees but no dead pile out front. Brood and stores are still there with too few bees to cover them.
What's going on: Now the more common nosema in North America, and easy to miss because it doesn't streak. Only a microscope or lab test tells it apart from N. apis.
What to do: Keep colonies strong and well fed, use young queens, replace old comb, and do a spore count on any colony that dwindles without a clear cause.
Easy to mistake for: Parasitic mite syndrome (PMS), Bees vanished, food left behind, Failing or poorly mated queen, Dwindling colony
Not enough good food
What you see: A colony that builds up slowly in spring, raises less brood, and makes no surplus while others in the same yard do.
What's going on: Too little pollen or nectar, or too few nurse or forager bees to use what's there. Poor fall nutrition means short-lived winter bees. Spring brood diseases add to it.
What to do: Feed sugar and pollen substitute when nothing's coming in, especially early spring and fall. Check the queen and do a mite wash, since they cause the same picture.
Easy to mistake for: Starvation, Dwindling colony, Parasitic mite syndrome (PMS), Failing or poorly mated queen
Nothing wrong
Most common: April to September
What you see: On a warm afternoon, a cloud of bees hovering in front of the hive, facing it, making wider and wider loops, with no pollen and no fighting.
What's going on: Young bees learning where home is before they start foraging.
What to do: Nothing. Robbing is frantic and has fighting; this is calm and over in a few minutes.
Easy to mistake for: Robbing, Swarm preparation
Viruses: ABPV, CBPV, IAPV, KBV
What you see: Bees trembling, crawling out the entrance and up grass stems unable to fly. Some are hairless, shiny and greasy-black, and their nestmates nibble at them. Sometimes thousands crawl out front, or huddle on the top bars in cool weather.
What's going on: A group of related viruses: acute and chronic bee paralysis, Israeli acute paralysis and Kashmir bee virus. Only a lab can tell them apart. Several are spread by varroa, and they turn up together in collapsing colonies.
What to do: There's no treatment for the virus itself. Do a mite wash and control mites, keep the colony fed, and requeen if it keeps happening. Rule out pesticide poisoning, which looks very similar, and robbing (old robber bees lose their hair too).
Easy to mistake for: Pesticide poisoning, Tracheal mites, Parasitic mite syndrome (PMS), Nosema apis, Robbing
Varroa mites and the viruses they spread
Most common: August to November
What you see: Spotty brood with a mess of dying brood that fits no single disease: melted, greyish snot brood, chewed-down cappings, larvae slumped in odd positions. Too few bees to cover the brood. Bees with crumpled wings, or crawling and greasy. Mites on bees and in drone brood.
What's going on: Not one germ. It's what a heavy varroa load and the viruses mites carry do to a colony, usually in late summer and fall when mites peak. Also called snot brood or idiopathic brood disease syndrome. Colonies this far along usually die in fall or over winter.
What to do: Do a mite wash. It will be high, so treat now. A brood break helps. A colony this far along may not recover, so combine it into a strong one if it's weak. PMS doesn't rope; if any dead brood does, test for AFB.
Easy to mistake for: European foulbrood (EFB), American foulbrood (AFB), Paralysis viruses, Starvation
Not a disease: poisoning
Most common: April to July
What you see: A sudden pile of dead and dying bees at the entrance or on the bottom board, many still twitching, spinning in the dirt or unable to fly. Dead brood dragged out, and the queen may stop laying. It can hit several hives in a yard the same day. Low-level exposure shows only as a colony that never thrives.
What's going on: Insecticides (and some fungicides) brought home by foragers or drifting onto the yard. Hive treatments used wrong can do it too.
What to do: Photograph it, freeze a zip bag of the dead bees as a sample, note what's been sprayed nearby, and report it to the PA Department of Agriculture. Move or cover the hives if spraying nearby is still going on. Give the colony water, food and time.
Easy to mistake for: Paralysis viruses, Starvation, Toxic nectar or pollen, Chilled brood
See it drawn in the Frame Guide →Brood Disease ID: pesticide kill →
Management
Most common: April and September
What you see: Frames in the middle of the brood nest packed with stored pollen, leaving little room to lay.
What's going on: Usually leftover from the last season or a heavy pollen flow. The bees normally use it up fast once brood rearing takes off.
What to do: Usually nothing. If it's choking the queen in spring, move one pollen frame to the edge of the brood nest and give her drawn comb.
Easy to mistake for: Honey-bound brood nest, Queenless colony, Entombed pollen
Nothing wrong
What you see: Sticky brown or reddish glue sealing cracks and gluing frames and boxes together, stringy when warm and brittle when cold.
What's going on: Tree resin the bees collect to seal gaps and coat the inside of the hive. It's antimicrobial. Some lines use much more than others.
What to do: Nothing. Wear gloves if it bothers your skin.
Workers attacking a queen
What you see: A tight, hard ball of workers clamped around the queen, or bees biting at a new queen's cage instead of feeding her. The queen may be killed.
What's going on: Most often a new queen released too soon, a queen from another colony, or upset after a rough inspection.
What to do: Drop the ball into a bucket of water or smoke it gently to break it up. Leave new queens caged longer and use a slow candy release. Don't release a queen while bees are biting the cage.
Easy to mistake for: The queen's court, Usurpation
Usually normal
Most common: May to July
What you see: Queen cells with a hole chewed in the side and the pupa gone. A queen that emerged normally leaves a neat round lid at the tip.
What's going on: The first virgin queen out goes around chewing into her rivals' cells so the workers will tear them down.
What to do: Nothing. A cell opened at the tip means a queen emerged; one opened on the side means a rival was killed. Look for eggs in two to three weeks.
Easy to mistake for: Waiting on a virgin queen, Two queens
Nothing wrong
What you see: A queen who goes limp and still after you've handled or marked her.
What's going on: It happens sometimes when a queen is held. She usually comes round in a few minutes.
What to do: Set her gently back on the comb near bees and leave her be.
Easy to mistake for: Dead or injured queen
Nothing wrong
Most common: May to July
What you see: A queen flying out of or back into the entrance on a warm afternoon, sometimes with a few workers.
What's going on: A virgin queen flies to a drone congregation area and mates with a dozen or more drones over one or several flights.
What to do: Don't open the hive during her flights. Check for eggs in about two weeks.
Easy to mistake for: A swarm
Laying break
Most common: July to August and October to January
What you see: Capped brood but no eggs or young larvae, and a small, slim queen.
What's going on: Queens ease off or stop laying in a dearth, after pesticide exposure or a big loss of nurse bees, before swarming, with some mite treatments, and every fall and winter. In late fall a small or empty brood nest is normal.
What to do: Check stores and feed if there's a dearth. If you can't find her, give a frame of eggs to test for queenlessness.
Easy to mistake for: Queenless colony, Waiting on a virgin queen
No laying queen
What you see: No eggs and no young larvae, a loud roar when you open up, bees running on the comb, maybe emergency queen cells. Nectar and pollen start filling the empty brood cells.
What's going on: The queen died, was lost on a mating flight, or was killed. Without young larvae to raise a replacement, the colony is hopelessly queenless and heads toward laying workers.
What to do: Look for eggs, not the queen. Give a frame of eggs and young larvae from another hive: if they build queen cells on it, they're queenless. If they don't, there may be a virgin queen you haven't found. Then requeen or let them raise one.
Easy to mistake for: Waiting on a virgin queen, Queen stopped laying, Laying workers
Bees stealing from bees
Most common: July to October
What you see: Frantic, zig-zagging flight at the entrance and at every crack, bees wrestling and dead bees piling up, and honey cappings torn open with ragged edges. Robbers fly in light and leave heavy.
What's going on: Bees from other hives stealing honey, mostly in a dearth, from weak or queenless colonies, or when honey, syrup or an open hive is left out. It also moves mites from hive to hive.
What to do: Close it down to a one-bee entrance or put on a robbing screen, seal cracks, and stop open feeding. During a dearth, inspect quickly or not at all. A wet sheet over a hive under attack can buy time.
Easy to mistake for: Orientation flights, Yellowjackets and hornets, Swarm preparation
Virus
Most common: April to June
What you see: Larvae dead, stretched out on their backs, their skin a tough sac of fluid going yellow-grey to brown. The head end is darker and turned up like a canoe or slipper. They lift out of the cell in one piece. Cappings may have a hole.
What's going on: A common virus that shows up most during spring buildup. Adult bees carry it without outward signs.
What to do: A strong colony usually clears it. Requeen if it keeps going through several brood cycles.
Easy to mistake for: American foulbrood (AFB), European foulbrood (EFB), Black queen cell virus
See it drawn in the Frame Guide →Brood Disease ID: sacbrood →
Nothing wrong
What you see: Bees standing tall with rear ends tipped down, a pale gland showing at the tip, fanning hard at the entrance, a swarm or a water source.
What's going on: Releasing a lemony pheromone that says 'this way home'. You see it after an inspection, when a swarm is going into a box, and at feeders.
What to do: Nothing. It's a good sign when you're hiving a swarm: the queen is probably in.
Easy to mistake for: Bearding and fanning, A swarm
Nothing wrong
What you see: One bee grabbing another and rapidly shaking her body up and down for a second or so.
What's going on: The most common bee signal. It seems to tell other bees to get more active, before foraging or swarming.
What to do: Nothing.
Easy to mistake for: Waggle dance
Small mammal
Most common: November to March
What you see: A pile of dead bees in winter, each one headless or with a hole in the thorax, and no nest like a mouse builds.
What's going on: Tiny shrews squeeze through gaps as small as 1 cm into wintering colonies and eat bees off the cluster. Uncommon.
What to do: Shrews fit through gaps of about 1 cm (3/8 inch), so in fall use an entrance guard with holes smaller than that and close any other gaps.
Easy to mistake for: Mice
Night visitors
Most common: April to October
What you see: Scratch marks and matted or dug-up grass at the entrance, mud on the lower box, and wads of chewed bee parts spat out in front. The bees get testy.
What's going on: Skunks scratch at the hive at night, scoop up the guards that come out and chew them. Night after night, that wears a colony down and makes it defensive.
What to do: Put hives on stands at least 18 inches high so a skunk has to stand up and expose its belly, and lay carpet tack strip or chicken wire in front of the entrance.
Easy to mistake for: Hot (defensive) colony
Beetle: Aethina tumida
Most common: June to September
What you see: Small (about 1/4 inch), oval black beetles running for the dark when you lift the cover, often penned in propolis in the corners and on top bars. In a bad case, slimy larvae (with legs) in the comb, honey running and fermenting, and a rotten-orange smell.
What's going on: A scavenger that takes over weak hives or ones with more comb than the bees can patrol. Larvae leave the hive to pupate in the soil.
What to do: Keep colonies strong and boxes matched to the bees. Beetle traps help. Extract honey supers promptly. A slimed-out hive needs that comb pulled (freeze or toss it) and the bees given less space.
Easy to mistake for: Wax moth, Flies and maggots, Fermenting honey
See it drawn in the Frame Guide →Disease & Pest ID: small hive beetle →
Beekeeper side
What you see: Thin, hot, bluish smoke, a smoker too hot to touch, or bees stinging a lot right after you smoked them.
What's going on: Hot smoke singes bees and riles them up, and too much or too little smoke both backfire.
What to do: Pack the fuel tight and puff cool, white smoke, a few puffs at a time. Put it fully out before you leave the yard.
Easy to mistake for: Hot (defensive) colony
Ran out of food
Most common: February to April
What you see: A colony dead in late winter or spring, the cluster sitting on brood with many bees head-first in cells, and no honey touching the cluster. Sometimes honey is only a few inches away.
What's going on: Late winter and early spring, when the colony is raising brood and burning stores fastest. A cold snap can strand the cluster away from its honey. March is the worst month in Pennsylvania.
What to do: Heft hives through winter and feed dry sugar, fondant or a candy board when they're light. In spring, keep feeding until real forage comes in.
Easy to mistake for: Parasitic mite syndrome (PMS), Pesticide poisoning, Dead colony: what killed it?, Bees vanished, food left behind
Not a disease: no food coming in
Most common: March to April and July to August
What you see: Shriveled larvae in open cells with no milky food around them, and bees pulling them out and dumping them. No honey or pollen near the brood, and eggs may disappear. Often in a dearth or right after a split.
What's going on: When food runs short the nurse bees stop feeding and eat brood to recover the protein.
What to do: Feed syrup and pollen substitute now. Check the rest of the yard, since a dearth hits every hive.
Easy to mistake for: European foulbrood (EFB), Brood being eaten, Starvation
See it drawn in the Frame Guide →Brood Disease ID: starved brood →
Fungus: Aspergillus
What you see: Mummies like chalkbrood, but rock hard and dusted with yellow-green powder. Rare.
What's going on: An Aspergillus fungus. It can infect adult bees too.
What to do: Wear a dust mask, because the same fungus can make people sick if they breathe the spores. Remove and replace the affected comb and keep the colony strong and dry. Rare enough that a lab confirmation is worth having.
Easy to mistake for: Chalkbrood
Bees replacing their queen
Most common: June to August
What you see: One to a few (rarely more than five) queen cells on the face of the comb in the brood area, not along the bottom edges, often over a tired, spotty pattern.
What's going on: The bees decided their queen is failing and are raising her replacement. Most common in summer. Mother and daughter may lay side by side for a while.
What to do: Leave them to finish it. Tear the cells down and you can end up hopelessly queenless. Check for eggs about three to four weeks later.
Easy to mistake for: Swarm preparation, Emergency queen cells
Colony getting ready to reproduce
Most common: May to June
What you see: Many queen cells (often more than five, sometimes twenty or more) hanging from the bottom edges and sides of frames, a crowded hive, a brood nest getting filled with nectar, and a queen who's slimmed down and laying less.
What's going on: Swarming is how colonies reproduce. Here, swarm season runs from about mid-May into early July.
What to do: Once they're committed, cutting cells rarely stops them and can leave you queenless. Split the colony to relieve the crowding: move the old queen into a nuc, or split the cells out. That turns a swarm you'd have lost into a second colony.
Easy to mistake for: Supersedure, Emergency queen cells, Honey-bound brood nest
Queen didn't join the swarm
Most common: May to June
What you see: Bees pour out and start to cluster, then drift back into the hive within minutes to an hour.
What's going on: The queen didn't make it out with them, often because she's clipped, can't fly or is still too heavy. She may be crawling in the grass in front.
What to do: Look for her in front of the hive. They'll try again, usually with the first virgin queen, so split them now or manage the queen cells.
Easy to mistake for: A swarm
Nothing wrong
What you see: A loose ring of a dozen or so workers facing the queen when she pauses, touching her with antennae and mouthparts.
What's going on: Attendants feed and groom her and pass her scent through the colony. A queen with very few attendants may be failing.
What to do: Nothing. A tight, hard ball of bees on a queen is different: that's balling.
Easy to mistake for: Queen balled or rejected
Hive condition
Most common: November to March
What you see: Water stains on the inner cover, wet wood, puddles on the bottom board, mold, and a dead or chilled cluster in winter.
What's going on: A winter cluster breathes out a lot of water. It condenses on a cold lid and rains back down on the bees, and wet bees chill and die. Moisture kills more colonies than cold does.
What to do: Give an upper entrance or vent, tip the hive forward so condensation runs out the front, and consider a moisture quilt or insulated lid.
Easy to mistake for: Moldy comb, Dysentery, Dead colony: what killed it?
Weather and ground
What you see: Hives leaning or tipped over, or lids off.
What's going on: Tall, top-heavy hives on soft or uneven ground go over in wind and rain. Animals rubbing on hives knock lids off too.
What to do: Set it back up right away and close it up. Level the stands, strap tall hives, and weight the lids.
Easy to mistake for: Bears, Vandalism or theft
Plant poisoning
Most common: May to June
What you see: Dead bees or off-colored brood with no pesticide use around and one plant in heavy bloom.
What's going on: A few plants make nectar or pollen that's toxic to bees. In North America the known ones are swamp buttercup and summer titi (which turns brood purple). Rare.
What to do: Usually passes when the bloom ends. Rule out pesticides first.
Easy to mistake for: Pesticide poisoning
Mite: Acarapis woodi
Most common: January to April
What you see: Bees with wings held apart at odd angles (K-wing), crawling bees that can't fly, a cluster that shrinks over winter and builds slowly in spring. The mites themselves are inside the breathing tubes and need a microscope.
What's going on: A tiny mite that breeds in the breathing tubes of adult bees. Much less common than it once was.
What to do: Grease patties (vegetable shortening and sugar) on the top bars and resistant stock both help. Its signs mimic many other problems, so check for varroa and nosema first.
Easy to mistake for: Paralysis viruses, Nosema apis, Deformed wing virus (DWV), Parasitic mite syndrome (PMS)
Mite: Tropilaelaps (Asia)
What you see: Tiny, light reddish-brown mites, much smaller and faster than varroa, running over brood comb and bees.
What's going on: An Asian brood mite that breeds even faster than varroa. It has not been found in the US, and the USDA surveys every year to keep watch.
What to do: Odds are it's something else, but this is one you report: drop some in alcohol and call the Pennsylvania state apiarist right away.
Easy to mistake for: Varroa mites
Usually a quiet supersedure
Most common: June to September
What you see: Two laying queens in the same hive, usually close together on the same frames.
What's going on: Mother and daughter after a supersedure. Fairly common in summer. The old queen usually disappears within weeks. Two virgins, on the other hand, fight to the death.
What to do: Nothing. If you want to keep one, split them into two colonies.
Easy to mistake for: Supersedure
Nothing wrong
What you see: A bee dragging a dead bee to the entrance, then flying off with it and dropping it a few feet away.
What's going on: A small crew of house bees keeps the hive clean by hauling out the dead.
What to do: Nothing. A sudden pile of dead bees out front is a different thing.
Easy to mistake for: Pesticide poisoning
A swarm taking over a hive
What you see: A small cluster of bees with a queen settles on the side of a hive. Its workers go in and kill the resident queen, then the rest move in.
What's going on: Mostly an Africanized bee behavior. Very rare in European bees and in Pennsylvania.
What to do: Check the queen and the temper afterward, and requeen if the colony turned hot.
Easy to mistake for: A swarm, Robbing, Queen balled or rejected
People
What you see: Hives missing, tipped over, lids pulled off, or equipment scattered, with no bear sign.
What's going on: Theft and vandalism happen most at out-yards far from houses.
What to do: Brand or mark your equipment, keep yards out of sight of the road, and consider a trail camera. Report theft to the police.
Easy to mistake for: Bears, Toppled hive
Mite: Varroa destructor
Most common: August to October
What you see: Reddish-brown, oval mites about the size of a pinhead with eight legs, on adult bees (often tucked between belly plates) or on pupae when you uncap drone brood. White crystals of mite droppings on the upper walls of brood cells.
What's going on: Varroa breeds in capped brood, feeds on bees and spreads viruses. Every colony in Pennsylvania has them, and an untreated colony usually dies within one to three years. Most winter losses trace back to mites.
What to do: Count them with an alcohol wash or sugar roll monthly in season and treat when you're over threshold. August is the critical month for the winter bees. You can't judge mite load by looking, because most mites are hidden in the brood.
Easy to mistake for: Tropilaelaps mites, Bee louse, Parasitic mite syndrome (PMS)
Nothing wrong
What you see: A bee running in a figure 8 or a circle, wiggling her rear in the straight part, with other bees following her.
What's going on: A forager telling others where she found food (or, on a swarm, a new home): direction from the angle, distance from how long she wiggles.
What to do: Nothing. Enjoy it.
Easy to mistake for: Shaking signal
New queen not laying yet
Most common: May to July
What you see: Opened queen cells (cut neatly at the tip), no eggs yet, and maybe a small, quick, slim queen with no court. The colony can be loud and jumpy.
What's going on: After a swarm or supersedure the new queen takes one to two weeks to mate, weather permitting, and a few more days to start laying.
What to do: Be patient. Give her two to three weeks from emergence before you worry, longer in bad weather. Don't add a new queen while a virgin is in there. A frame of eggs tells you: no queen cells on it means a queen is present.
Easy to mistake for: Queenless colony, Queen stopped laying
Moth: Galleria and Achroia
Most common: June to September
What you see: Silk webbing and tunnels through comb full of droppings, and cocoons glued into boat-shaped grooves chewed in the wood. Grey-brown moths at night.
What's going on: A comb scavenger, not a colony killer. Strong colonies keep it out. It moves in after a colony weakens or dies, and wrecks stored comb.
What to do: Ask why the colony was too weak to guard its comb. Shrink the space or combine. Freeze stored frames, then keep them cool, light and airy.
Easy to mistake for: Small hive beetle, Bald brood, Bee louse
See it drawn in the Frame Guide →Disease & Pest ID: wax moth →
Nothing wrong
Most common: November to March
What you see: Bees packed in a tight ball across a few frames in cold weather, often up near the top of the stack by late winter.
What's going on: How bees survive winter: they shiver their flight muscles to make heat and keep the center of the ball warm.
What to do: Leave it alone. Heft for stores, and add dry sugar or fondant on top if it's light.
Easy to mistake for: Starvation
Wasps: Vespula and Vespa
Most common: August to October
What you see: Yellowjackets scavenging dead bees out front, hovering at the entrance and grabbing bees, or slipping inside to steal honey. Big brown-and-yellow European hornets picking off bees, even at dusk.
What's going on: Mostly scavengers until late summer and fall, when their colonies peak and other food runs out. They only take over a colony too weak to guard itself.
What to do: Reduce the entrance or add a robbing screen, keep colonies strong, combine weak ones, and don't leave honey or syrup out. Deal with nearby nests if you can find them. Traps catch a lot but rarely make a real dent. A big dark hornet with yellow legs isn't known in Pennsylvania; report one.
Easy to mistake for: Robbing