Certan for Wax Moth Control
Protecting stored beeswax comb from wax moths is a major task for beekeepers. Certan B402 is a biological solution to this vexing problem. While not designed to correct an active infestation moth infestation, it will help prevent future damage. In this article, I will share how I use Certan B402 for wax moths, how to apply it and when.

Wax moth damage happens in live hives too in some situations. This usually occurs when the colony population is too small to patrol the comb. But, it is the loss of valuable drawn comb in stored honey supers that is most frustrating and can result in less honey surplus next year.
What is Certan B402?
Known among beekeeper circles as “Certan”, the product is sold today as B402 (Certan) in the United States and B401 (Certan) in other parts of the world where available.
This is not a chemical insecticide. Safe and environmentally friendly, it consists of a concentrated solution of Bacillus thuringiensis– a subspecies of aizawai.
This bacterium produces protein crystals that are toxic to wax moth larvae—but harmless to honey bees, humans, and other beneficial insects.
Years ago, Certan was a favorite tool for beekeepers but it was off the market for a while. Thankfully, Certan received approval from the EPA for use by beekeepers again and it is suitable for organic farming operations.

How it Works
Certan leaves a protective layer over the comb. As wax moth larvae begin to feed on the wax, their digestive system is disrupted by the toxins. This causes the moth larvae to stop feeding and die.
Because of the way Certan works, it is only effective against wax moths in the larval stage. It does not kill adult moths or eggs. Clearly this is why it is viewed as a preventative and not a control for a hive already in trouble.
Formulation
Certan is most often sold in concentrated liquid form and is diluted with water before use. A single application can remain effective for months, offering long-term protection during storage.
The concentrated liquid is mixed with water to create a 5% solution. It is important to shake the bottle well before mixing and shake the sprayer well during application.
Treatment solution should be used within 24 hours of mixing to maintain effectiveness.
The manufacturer (Vita-Health) maintains that a 5 oz bottle of B402 Certan will treat approximately ( enough to treat 100 deep frames, 150 medium frames, or 200 shallow frames). But, of course this depends on how heavily you apply the product.
How to Use

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You don’t need any fancy supplies to use this product. Purchase the Certan B402 from a bee supplier or buy Certan online), you will need a few simple measuring tools, a good sprayer and a container with a lid.
Method of Application
I am sharing with you MY method for using Certan B402 to protect wax comb. Other beekeepers may use different methods.
But, always read and follow the manufacturer’s instructions – they are your best guide for legal use of the product.
After mixing the solution, each side of the comb surface is lightly sprayed. This is not applied in the hive but rather to comb that is not currently in use.

My honey frames have been removed from the extractor and cleaned of any honey residue by the bees – they are now dry. If I have any unused brood frames I give them a spray too – why not?
We are going to make a small recipe – you can double it for larger amounts of solution. However, keep in mind that you need to use it within 24 hours.

Step by Step
1. If this is your first time opening the bottle-you will find a foil seal. Shake the product vigorously (it normally settles during storage). Then, remove the seal – you may need a knife or scissors.
2. Use your measuring cup to put 2 cups of water in the pint jar. (To make 2 cups of spray, I use a pint jar with a lid.
3. With a measuring spoon put approximately 4.8 (almost 5) teaspoons of B402 Certan into the jar of water. You don’t have to be precise – this is not rocket science. Just get it close.
4. Place the lid on the jar and shake, shake, shake to completely mix the water and solution together.

5. Pour your solution into a good quality spray bottle. Test your sprayer with water before adding the Bt mixture. Cheaper sprayers will work but they are unreliable and may result in losing some of your product.
Lightly but thoroughly spray each side of the honeycomb in your frames. You want good coverage but do not try to fill the wax cells with water- just a nice mist over all the surface.

6. Then, place the sprayed frames of comb in the sun or any place with good air flow and allow them to dry completely. Once dry, they are ready to store in whichever manner you choose- or use again in the hive.
Expert Tips
- can be applied to any frames from the hive
- frames that have had brood in them are more attractive to moths
- only mix as much solution as you can use in a day. It is much better to have to mix twice rather than fail to have your comb protected by using old “dead” protection
- agricultural aizawai Bt is used by some beekeepers – but they are not labeled for use in bees

When to Use Certan
The most common time to apply Certan is after you complete the honey harvest. Once empty frames of comb are removed from the honey extractor and allowed to dry – it is time to spray them before storage.
This application should kill any young wax moth larvae that develop. You can not rely on your sight to find moth eggs. Some beekeepers freeze their comb before storage – that is a great plan.
However, adult moths can still get into your comb and lay eggs if it is not stored in an airtight container.
A single application gives good results that last though the next season. I have had excellent results with some sprayed combs being protected beyond a year.

Don’t Wait too Late
A strong colony can repair a small amount of moth larvae damage. However, there comes a point when it is too little too late for preventative treatments.
If your frames are full of webbing, frass and other signs of damage, it is time to install new beeswax foundation. Your colonies effort will be better spent building out new comb rather than trying to replace a mess.
FAQs
B402 Certan is a registered product that uses Bacillus thuringiensis, a subspecies of aizawai to control wax moths in honeycomb. It is natural and not harmful to humans or honey bees.
Yes, B402 Certan can be used on any frames from the hive. Darker comb that has been used for brood rearing is especially attractive to wax moth larva – be sure to spray those well.
It is not advisable to mix a batch of solution larger than what you can use in 24 hours. The solution’s effectiveness lessens over time.
For frames with significant wax moth damage – it is best to start over with new foundation. While a strong colony can repair small areas, it is not worth their time to make major repairs.
A Final Word
Using Certan B402 is a simple and effective way to protect your valuable drawn comb from wax moth damage during storage. It is a simple process that anyone can do. Don’t let your stored comb be destroyed by moth eggs that may be there – even if you don’t see them.