How to Control Pests and Wax Moths in a Beehive

How to Control Pests and Wax Moths in a Beehive

I once stored eight supers of good drawn comb in a shed for the dry season, proud of how much work the bees had saved me. When I opened the shed three months later, the combs were gone. In their place were webs thick as cotton wool, black tunnels, and fat white caterpillars the size of my little finger. A whole season of bee labour had been eaten while I was not looking. The worst part was that the moths had not attacked a weak colony. They had attacked the one thing I had left defenceless.

Here is the direct answer. Wax moths are a symptom more than a cause. Strong colonies defend their combs well, and moths mostly destroy weak colonies, empty hives, and stored combs. You control wax moths and other hive pests by keeping colonies strong and queenright, keeping the hive size matched to the colony, cleaning up debris and old black comb, storing spare combs so moths cannot reach them, using a proper stand with ant barriers, watching for beetles, mites, and other invaders, and acting quickly when you find them. Chemical treatments are a last resort and should only be used as advised locally. Most losses come from neglect, not bad luck.

Let me walk you through the main pests, how to spot them, and the routine I follow.

What most farmers get wrong

The first mistake is blaming the moths. Farmers find wax moth larvae in a failing hive and conclude that the moths killed the colony. In most cases, the colony was already weak, queenless, diseased, or starving, and the moths moved in afterward.

The second mistake is leaving empty hives and spare combs lying around. Wax moths love dark, undisturbed, warm places with old comb, especially combs that have had brood in them, because they contain pollen and cocoons. A stack of spare supers in a shed is a moth nursery.

The third mistake is keeping oversized hives for small colonies. If the bees cannot cover the combs, the uncovered combs are open to moths and beetles.

The fourth mistake is ignoring the floor of the hive. Debris, dead bees, and wax scraps that pile up provide food for moth larvae and other pests.

The fifth mistake is using the wrong chemicals. Some products sold to kill moths or other pests can contaminate wax and honey, harm bees, or be dangerous to the beekeeper. Others are banned in many places.

The sixth mistake is overlooking the other pests. While you worry about moths, ants, beetles, mites, wasps, termites, rodents, and predators may be doing more damage.

The seventh mistake is waiting. A moth infestation in stored combs or a weak hive can ruin everything in a few weeks, especially in warm, humid weather.

Wax moths: what they are and how they hurt

Wax moths are small, greyish-brown moths. The adult moths do not feed. The damage is done by the larvae, which hatch from eggs laid in cracks and crevices in the hive or in stored comb. The larvae tunnel through the wax, feeding on pollen, cast skins, and the remains of brood, leaving silky webbing and dark droppings. As they grow, they can destroy whole combs, and in a weak colony, they can smother the brood and kill the colony. The larvae then spin tough cocoons, often on the woodwork, and may bore into the wood, leaving grooves and pits in the frames and boxes.

Wax moths thrive in warm, humid conditions. Their life cycle is faster in hot weather, so the problem can go from a few larvae to a major infestation in a few weeks in the tropics. Cool weather slows them down, and cold can kill the eggs and larvae.

Signs of wax moth infestation include silky webs across the combs, tunnels filled with webbing, black grains of frass (droppings), cocoons on frames and boxes, damaged cell walls, a sour smell, and larvae wriggling when you open the hive. In severe cases, the whole comb collapses into a mass of webbing.

Keep colonies strong: your best defence

This is the single most important thing you can do.

Maintain a good queen. A queenright colony with a laying queen produces plenty of workers, who patrol the combs and remove moth eggs and larvae. Check regularly that the queen is laying. Replace old or failing queens.

Match the hive to the colony. Give the colony only as much space as the bees can cover and defend. Use a divider or a smaller box for small colonies, and add space as they grow. Remove empty supers that the bees are not using.

Feed during dearth. Starving colonies weaken, and weak colonies lose to pests. Ask local bee experts about feeding practice in your area.

Unite weak colonies. Two weak colonies often succumb to moths and other pests. One strong colony is better than two weak ones.

Prevent disease and mites. Sick colonies become pest targets. Monitor and manage diseases and parasites such as varroa where they occur, using approved methods.

Avoid unnecessary disturbance. Frequent opening disrupts the colony and gives pests an opportunity.

Clean hives, clean combs

Clean the bottom board. Scrape off and remove debris, dead bees, and wax scraps regularly. Use a hive tool, and dispose of the rubbish away from the apiary. In the tropics, I do this at each inspection.

Replace old combs. Old, dark combs hold cocoons, disease organisms, and pollen that attract moths. Many beekeepers replace a portion of the brood combs each year, so that no comb stays in use for too long. Ask your local association about rotating combs. Melt down very old comb and process the wax carefully, in a safe way, keeping flame away from the wax.

Fix cracks and gaps. Seal cracks in the hive body and woodwork that give moths hiding places. Keep boxes in good repair, with tight-fitting lids and floors. Do not leave gaps that are too large for the bees to guard.

Reduce the entrance when needed. In weak colonies, a smaller entrance is easier to defend against moths, ants, wasps, and robbers.

Storing combs and equipment safely

Stored comb is the most vulnerable. Here is what I do.

Store only clean, bee-free combs. Extract honey and let the bees clean the combs, if you can, before storing. Remove any leftover honey or pollen that attracts pests.

Keep stored supers in a cool, dry, well-ventilated place. Moths prefer warm, dark, still conditions. Stack supers with gaps, such as by placing wooden slats between boxes, to let air and light in. Some beekeepers hang combs in an airy shed so light and airflow discourage moths.

Seal them from moths. Wrap stacks in plastic sheeting or put them in moth-proof containers, with a tight lid and no gaps. Check for existing moth eggs or larvae before sealing, since sealing in infested combs makes the problem worse.

Use cold or freezing where possible. Freezing combs for a period kills moth eggs and larvae. Where freezers are available, freezing frames before storage is a safe, chemical-free method. Ask your local association how long to freeze for in your climate.

Use sunlight and heat carefully. Wax moths dislike light and cold, and can be killed by heat above a certain temperature, but heating wax risks melting it. Ask experienced beekeepers about methods that work in your area before trying.

Inspect stored combs regularly. Look at them every few weeks for webbing, frass, and larvae. Remove and treat infested combs right away.

Give the combs back to strong colonies. Strong colonies can clean up and repair damaged combs. Do not put heavily infested combs on weak hives.

Be careful with chemical treatments. Some products are used to fumigate stored comb, but many are dangerous, leave residues in wax and honey, or are banned. Do not use mothballs (naphthalene) or other household pesticides in comb storage, because the fumes taint wax and honey and can harm bees and people. If you are considering any treatment, ask your bee inspector or beekeeping association what is legal, safe, and approved in your country, and follow instructions exactly. Many beekeepers prefer non-chemical methods.

Other common pests and how to deal with them

Ants. Put hive stands in containers of water or oil that ants cannot cross, keep vegetation trimmed so there are no bridges, and clean up spills of syrup and honey. Destroy ant nests near the apiary with safe methods. Check barriers regularly.

Small hive beetles (where present). The adult beetles and larvae feed on honey, pollen, and brood, and the larvae ferment and slime the honey. Strong colonies often keep them in check. Reduce hive space, keep the apiary clean, avoid leaving supers of wet honey, extract honey promptly, and use approved traps as advised locally. Ask your bee inspector for guidance, and report as required.

Varroa mites and other parasites. Where varroa is present, monitor mite levels and treat with approved methods at the right times. Do not use unapproved chemicals. Ask your local bee health officer about monitoring and control.

Wasps and hornets. They may attack weak colonies and rob honey. Reduce the entrance, trap wasps near the apiary, and keep colonies strong. Do not use poisons that bees can reach.

Termites. Use hard or treated timber, raise hives on stands with termite protection, and keep the ground around hives clear. Check wooden stands and boxes for mud tubes.

Rodents and lizards. Fit mouse guards at entrances, especially in cool weather, and block holes. Keep the area clear of tall grass and rubbish. Lizards and some birds that eat bees are hard to stop, but strong colonies and good siting help.

Larger predators. In some regions, honey badgers, monkeys, and bears can destroy hives. Use hanging hives, strong platforms, electric fencing, or other methods used locally.

Robbing bees. Strong colonies sometimes rob weak ones. Reduce entrances on weak colonies, avoid leaving honey exposed, and do not feed in the daytime.

A simple routine that works

I keep a routine so that pests rarely get a hold.

At each inspection, I check the queen and brood, look for signs of moths, beetles, ants, and mites, scrape the bottom board, and reduce or enlarge the space to suit the colony. I replace cracked boxes and weak combs.

Every month or two, I check ant barriers, clean around the stands, and inspect stored combs.

Before storage, I clean and freeze or air the combs, then store them in a cool, dry, ventilated, pest-proof container.

At the end of the season, I unite weak colonies, requeen where needed, and make sure each colony goes into the dry or cold season with enough bees and stores.

I keep a record of what I find, the treatments used, and how the colonies respond.

Warning signs to watch for

I stay alert for webbing and tunnels in the combs, small larvae wriggling in the debris, black frass on the bottom board, a weak colony with a falling bee population, a sour smell, slimed honey, ants trailing into the hive, beetles scuttling over combs, bees chewing off cappings in the brood area, damaged wooden parts, and fewer bees at the entrance. Any of these means open the hive and look.

What I would do differently if I started today

I would never store comb without cleaning it and checking it first.

I would build a moth-proof storeroom or buy sealable containers before I needed them.

I would keep my colonies strong, and unite the weak ones early.

I would clean the bottom boards at every visit.

I would stay away from household pesticides, and ask my association before using any treatment.

And I would check my stored combs every month, whether or not I thought they were fine.

Frequently asked questions

Do wax moths kill healthy colonies?
Rarely. Strong colonies defend their combs well. Wax moths mainly attack weak or queenless colonies, empty hives, and stored combs.

How do I stop wax moths in stored combs?
Store clean combs in a cool, dry, ventilated, moth-proof way, check them regularly, and freeze combs before storage if possible. Avoid household chemicals.

Can I use mothballs to protect my combs?
No. Mothballs and many household pesticides can contaminate wax and honey and harm bees and people. Ask your local bee inspector about safe, approved methods.

What do wax moth larvae look like?
Creamy white to grey caterpillars with darker heads, which spin silky webs and tunnel through comb, leaving black droppings.

How can I prevent ants from entering my hive?
Use stand legs in water or oil moats, keep vegetation trimmed, avoid spills of syrup and honey, and destroy ant nests nearby.

The advice worth bookmarking

Pests attack the weak and the neglected, so keep the colony strong, the combs clean, the stores sealed, and the hive visited, because a beekeeper who looks often rarely has to fight.