# using BT for wax moth control



## Michael Bush (Aug 2, 2002)

Try a search from the beesource.com main page. You'll find hundreds of discussions on this topic.


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## Rader Sidetrack (Nov 30, 2011)

The variety of Bt for use against wax moths is _Bt v. aizawai. _One online source is:
http://www.hidhut.com/xentari-p-31.html


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## TheBuzz (Feb 8, 2012)

Why not freeze them? Probably put them outside now and get it done


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## beegeorge (Apr 19, 2012)

Thanks for all the help,, now all I need is the recipe for the right concentration?

Buzz- unfortunately it does not freeze that well down here in the Carolinas


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## BEE STALKER (Feb 12, 2012)

I freeze for SHB, then spray Xentari. The stuff works as advertised. 

I use a Tablespoon for one gallon, it's a bit more than the label says, but convenient to measure. A gallon will easily spray 100 deep frames. If you are a hobbyist, one bag will last a lifetime.

It's also great for strawberries and other garden worm targets, completely organic...


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## beegeorge (Apr 19, 2012)

I thank EVERYONE!!!


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## Phoebee (Jan 29, 2014)

Rader Sidetrack said:


> The variety of Bt for use against wax moths is _Bt v. aizawai. _One online source is:
> http://www.hidhut.com/xentari-p-31.html


WHOOOOAAAA! Granted, I'm a noo-bee, but this is a topic I was looking up a couple of weeks back. The only "insecticide" we use is mosquito dunks in rain barrels, and I was looking up if it is safe for bees. The strain used in dunks should be OK. But _B. t. aizawai_, that one scares me. I believe that's the one that kills bees.

Here are my notes:

From http://www.epa.gov/oppsrrd1/REDs/0247.pdf
This is ref 3 of another report that says one subspecies of Bt is toxic to bees, but not which one. From this, mosquito dunks should be OK. Tracking down the specifics:

http://npic.orst.edu/factsheets/BTgen.pdf

Table 2 B. thuringiensis subspecies israelensis
GUIDELINE MRID RESULT
154-23 green lace-wing 418427-08 16-day LC > 1.5 x 10 cfu/g diet; 16-day NOEL = 2.5 x 10
larvae cfu/g
50
8 4
parasitic 418427-09 30-day LC > 7.9 x 10 cfu/g diet
hymenoptera
50
7
predaceous 418427-10 9-day LC > 1.8 x 10 cfu/g diet
coleopteran
50
8
154-24 honey bee 418427-11 5-day LC50 > 7.0 x 10 cfu/g diet
7

(i.e. B. thuringiensis subspecies israelensis has little effect on honeybees. This is the strain used in mosquito dunks, and it targets mosquitos and certain flies.) 


Table 4 B. thuringiensis subspecies aizawai
GUIDELINE MRID RESULT
154-23 green lace-wing 419943-21 NOEL = 10,000 ppm
larvae
422453-01 Toxic to larvae at 10x field rate
parasitic 419943-19 NOEL = 100 ppm
hymenoptera
predatory mite 419748-09 1x field rate resulted in 24% corrected mortality
predaceous 419943-20 NOEL = 10,000 ppm
coleoptera
429421-01 NOEL = 1566 ppm
*154-24 Honey bee 419748-08 Highly toxic; LE50 = 15 ppm*

With the exceptions of MRIDs 414434-09 and 422453-01, the nontarget
insect B. thuringiensis subspecies kurstaki, B. thuringiensis subspecies israelensis,
B. thuringiensis subspecies tenebrionis (CryIIIA) and B. thuringiensis subspecies
21, aizawai studies show little to no toxicity or pathogenicity in the tested neuroptera,
hymenoptera, coleoptera, arthropod and annelida group indicator species. *The
above honey bee data indicate a high degree of toxicity for B. thuringiensis
subspecies aizawai and minimal toxicity for B. thuringiensis subspecies kurstaki,
B. thuringiensis subspecies israelensis and B. thuringiensis subspecies tenebrionis.*

With the exception of honey bee and earthworm testing, all of the nontarget
insect studies listed above were graded as supplemental. However, since the
Agency currently waives the requirement for nontarget insect data (but not
honeybee testing) for registration, no additional data are required. These data are
routinely waived because Bacillus thuringiensis does not cause epizooatics in the
field; it functions by a toxic mode-of-action.
(This strain is effective against butterflies and moths, so might be used in gypsy moth control. It appears to have a secondary toxin, deadly to many other organisms including bees, so beware of this one if gypsy moth spraying is scheduled.)


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## Rader Sidetrack (Nov 30, 2011)

Phoebee said:


> The only "insecticide" we use is mosquito dunks in rain barrels, and I was looking up if it is safe for bees. The strain used in dunks should be OK. But _B. aizawai_, that one scares me. I believe that's the one that kills bees.


The Bt variety that targets mosquito larva is _israelensis_.

The EPA document you linked is 100+ pages. Perhaps you could identify where you believe that document says that v. _aizawai _is a problem for honeybees?

In the meantime here is a less complicated Bt reference from Colorado State University: 


> The specific activity of Bt generally is considered highly beneficial. Unlike most insecticides, Bt insecticides do not have a broad spectrum of activity, so they do not kill beneficial insects. This includes the natural enemies of insects (predators and parasites), as well as beneficial pollinators, such as honeybees. Therefore, Bt integrates well with other natural controls. For example, in Colorado, Bt to control corn borers in field corn has been stimulated by its ability to often avoid later spider mite problems. Mite outbreaks commonly result following destruction of their natural enemies by less selective treatments.
> 
> _More here:_http://www.ext.colostate.edu/pubs/insect/05556.html


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## Phoebee (Jan 29, 2014)

Sorry it is so sloppy, but the cut and paste formatting doesn't translate.

I indicate in my notes that the mosquito dunk subspecies is OK ... that is what I was looking up.

Table 4 in that first EPA link is where the bee toxicity is. And yes, I had to plough thru a lot to find it. Very tedious. I've made the specific line bold.

The notes below that suggest that two other subspecies should be effective against moths without serious harm to honeybees. The mosquito dunk kind does not kill moths or bees. I put that in bold as well.


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## Rader Sidetrack (Nov 30, 2011)

Perhaps you may wish to revisit Table 4 and its supporting references.

Note from section C.1. of the EPA document (just above where Table 4 is located):


> 1. Ecological Toxicity Data
> 
> The Agency concludes that toxicity and infectivity risks due to delta-endotoxin effects to nontarget avian, freshwater fish, freshwater aquatic invertebrates, estuarine and marine animals, arthropod predators/parasites, [HIGHLIGHT] honey bees, annelids and mammalian wildlife will be minimal to nonexistent [/HIGHLIGHT] at the label use rates of registered B. thuringiensis active ingredients.
> 
> http://www.epa.gov/oppsrrd1/REDs/0247.pdf


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## Phoebee (Jan 29, 2014)

I read that as the effects when used generally IN THE ENVIRONMENT at recommended doses. I don't read that as using on comb in the hive.

It does appear, though, that the document contains more than one Table 4, with no apparent change in section number that I can see. Check page 20.

With two other subspecies to choose from, why use the one with that warning about honeybee toxicity?


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## KQ6AR (May 13, 2008)

I buy my BT from sundance, its should be listed in the for sale section of the forum.


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## KQ6AR (May 13, 2008)

Here's all the msds information on the correct strain.
http://www.valent.com/agriculture/products/xentari/index.cfm


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## Rader Sidetrack (Nov 30, 2011)

The _For Sale_ thread where _Sundance _offered Bt v. _aizawai_ has been deleted.


> With two other subspecies to choose from, why use the one ..

You can use whatever variety of Bt you want. But the variety that targets wax moths is _aizawai, _so other varieties aren't much use on comb.


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## BEE STALKER (Feb 12, 2012)

Interesting.

I see no ill effects of using Xentari. This study actually has the bees (Bumblebees) ingesting it in feed:

http://www.ncbi.nlm.nih.gov/pubmed/20024947

I doubt I give them enough to kill them, but if I can keep the mites from killing them, maybe I'll find out..


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## Phoebee (Jan 29, 2014)

All I can say is, Table 4 on page 20. Not my claim ... this is the EPA. Maybe they found a strain that was OK, but I'll take an official government document over an advertising claim. Not that I think the government is always right, but where pesticide safety claims are being made ....

http://www.epa.gov/oppsrrd1/REDs/0247.pdf


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## Phoebee (Jan 29, 2014)

BEE STALKER said:


> Interesting.
> 
> I see no ill effects of using Xentari. This study actually has the bees (Bumblebees) ingesting it in feed:
> 
> ...


What I read from that link:

RESULTS: 

Exposure of bumblebees dermally or via treated pollen to either of the two Bt formulations at their field recommended rates (0.1%) caused no reduction in survival. *However, when applied in the feeding sugar water, aizawai killed all workers at a concentration of 0.1%,* but this lethal effect was lost at 0.01%. With respect to reproductive effects, kurstaki was harmless, while *aizawai at 0.1% delivered in the feeding sugar water and pollen reduced reproduction by 100 and 31% respectively.* Lower doses of 0.01% aizawai in the sugar water showed no more effect. In addition, kurstaki at 0.1% and aizawai at 0.01% in the feeding sugar water did not impair the foraging behaviour, resulting in normal nest colony performance.


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## BEE STALKER (Feb 12, 2012)

Yes, I saw that. I don't put it in the feed.


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## Rusty Hills Farm (Mar 24, 2010)

BtA does *not* go in the food supply. It gets sprayed on the stored comb and prevents a moth infestation. I used it while I was still in Florida (at the recommendation of the local bee inspector, which is how I heard of it in the first place) and it had no ill effects on my bees for all the years I used it. It is a much safer and more benign alternative to the moth chemicals sold by the supply houses.

JMO

Rusty


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## Phoebee (Jan 29, 2014)

Maybe I misunderstood. I thought bees use comb for three purposes, storing honey, storing pollen, and raising brood (which lie in a pool of food).

Looking at the manufacturer literature, I see no specific mention that it is safe for bees, although I admit I didn't go through all if it. I reviewed the MSDS, but those are targeted at human safety and I didn't expect anything on bees. Is there specific guidance for use on comb or with bees?


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## ChuckReburn (Dec 17, 2013)

Phoebee said:


> Maybe I misunderstood. I thought bees use comb for three purposes, storing honey, storing pollen, and raising brood (which lie in a pool of food).
> 
> Looking at the manufacturer literature, I see no specific mention that it is safe for bees, although I admit I didn't go through all if it. I reviewed the MSDS, but those are targeted at human safety and I didn't expect anything on bees. Is there specific guidance for use on comb or with bees?


Curious, how much drawn comb do you have at the moment? And other than a large freezer, how would you propose controlling wax moth in 20 supers?


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## Rusty Hills Farm (Mar 24, 2010)

> Maybe I misunderstood. I thought bees use comb for three purposes, storing honey, storing pollen, and raising brood (which lie in a pool of food).


Yes, but BtA is for comb--empty comb--that is used by the bees to store honey. The comb that is used to raise brood/store pollen remains on the hive where the bees can protect it. But the comb in the honey supers is vulnerable after it has been extracted and is being stored. This is when it is sprayed with BtA. The alternatives are the moth crystals that are sold by the bee supply houses. BtA simply does a better job and, being a biological and organic control, affects only the wax moths, both greater and lesser. I use it because I always considered it to be the most benign substance I have found to control moths without killing everything else that touches it. Being from the deep Deep South, moths have really been a problem and I just never had freezer capacity to handle all those empty frames.

HTH

Rusty


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## Phoebee (Jan 29, 2014)

I've got none at the moment. I sympathize, I know this is a problem but I'm amazed that Bta is considered for use with honeybees, as it is the only one of the four with any significant effect on bees.

You guys all seem positive that Bta is the only strain effective against wax moths. I have no specific information on that, but _B. thuringiensis _subspecies _tenebrionis_ and _B. thuringiensis _subspecies _kurstaki_ are generally effective on Lepidoptera. I.e. moths and butterflies. Has anyone considered these? 

Here's an option I use on stored food I don't want larvae eating: put it in a closed container and inject carbon dioxide (this is a prepper thing). I expect insect larvae to be fairly sensitive, but if you go to about 80% CO2 it will kill anything that breathes. 2% will kill humans. Anybody tried that on stored comb? I learned this trick from a conservator at the Smithsonian ... this is one of their favorite ways of keeping bugs from eating national treasures.


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## rweakley (Jul 2, 2004)

I have used the Bt that Sundance had for sale here on Beesource. Which ever variety it is, because he has sold 2 different kinds, but both worked fine to stop wax moths and didn't hurt the bees. I have gone as far as pulling frames from an active hive (mostly empty frames) sprayed them down and put them right back in the hive. None of them died. My only problem is I lose track of what has been treated and what hasn't and need to be more diligent in just spraying them all when they go into storage.


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## BEE STALKER (Feb 12, 2012)

I use it on stored brood comb also. I assume the concentration I use is below the threshold indicted. I can also imagine that after a brood cycle, the bacilli are on the other side of the cocoon and not in direct contact to the bees. 

Wax moths much prefer brood comb. I see 0 wax moth activity in the treated comb and no apparent ill effects to the colony. 

I did send an E-Mail to the manufacturer specifically asking about applying it directly to comb.

Wonder what they'll say.....


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## Rusty Hills Farm (Mar 24, 2010)

From Clemson University:

http://www.clemson.edu/extension/beekeepers/publications/wax_moth_ipm.html

Phoebee asked about carbon dioxide:


> Carbon Dioxide Treatment: carbon dioxide can be used as a fumigant to control wax moths in stored comb or comb honey. Air-tight treatment rooms or fumigation chambers are required to hold 80-98% carbon dioxide levels which have to be maintained continuously for up to 5 days at the lower levels to kill all life stages of wax moths. At the highest level (98% carbon dioxide) with a temperature of 100°F and relative humidity of 50%, only 4 hours are required to kill all life stages of the wax moth. Precaution: although no harmful carbon dioxide residues are left behind on treated comb or inside the fumigation chamber following use, a fully charged carbon dioxide room is hazardous to humans and can result in death.


And under biological control:


> B401, a microorganism, is a product manufactured by Vita-Europe Ltd. for the biological control of wax moths, but it is not currently registered for use in the US. The product is a bacterium, Bacillus thuringiensis subspecies aizawai that is manufactured specifically for wax moth control in stored comb. The material is formulated to kill young wax moth larvae as they attempt to feed on comb and must be used as a preventive before combs are infested. B401 leaves no residue on comb and it is harmless to bees and humans. Some other strains of Bacillus thuringiensis are toxic to bees and humans, so beekeepers must resist the temptation of using other BT products. B401was marketed in the US several years ago by the trade name Certan®. The product directions called for a mixture of one part Certan® to 19 parts water to be sprayed on both sides of every frame for effective wax moth control. Once mixed the solution must be used the same day. One application of the product gives wax moth protection in stored comb until the next season.


Note that Certan has since been replaced by Xen-Tari which is also BtA and legal for use in the U.S.A. Their website says it is approved for my home state of Alabama. I use 1/2 tsp in a gallon of water and spray it on stored comb.

HTH

Rusty


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## Gypsi (Mar 27, 2011)

I got it from sundance, didn't hurt my bees, did limit wax moth damage in stored frames. If the comb is fresh new and covered with bees I don't spray it. If I am putting it up in the fall in the shed I spray it


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## Phoebee (Jan 29, 2014)

That's more like it. The suspicion (not followed up in what I've read so far), is that Bta has an additional toxin responsible for its much wider range of harm. If a particular strain has been produced that lacks this extra effect, it is likely as well-targeted as the other Bt strains. But gosh, I gotta see proper application data on this first hand for what I'm applying.

See, for me, the genus Bacillus just makes the hair on my biologist neck stand on end. One cousin of Bt, _B. anthracis_, is just pure death in an aerobic gram-positive spore-forming weaponizable rod. Every time I see Bt sprayed against gypsy moths I think about how easy this stuff is to brew (easier than beer), and how much we need to keep an eye on spray planes.

Eh, sorry Gypsi, no offense intended.

How much comb are we talking about? For me, a few plastic storage containers would suffice for CO2 fumigation. I'd just leave it sealed in the storage container, nice and clean, no other bugs or crud.


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## Tenbears (May 15, 2012)

Figure 50 ten frame hives all with 2 or 3 supers extracted at season end. I am storing between 1200 and 1500 frames over until put back on the hives. Much easier to mix BT in a 25 gal agra sprayer. give them all a spritz and place them back in the supers. stack the supers and be done with it. I would need 500 storage containers. And I am a small operation.


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## jmgi (Jan 15, 2009)

So, just to get this straight, this particular type of Bt that is recommended for stored comb, can be used on brood comb that has honey and pollen still in it, and will not hurt the bees, correct? Because I always have lots of extra brood comb (containing some honey and pollen) around during the active wax moth season not being used, way more comb that can be put in a freezer.


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## Michael Bush (Aug 2, 2002)

Bt was approved for use on combs in beehives in the US but the certification lapsed as it wasn't financially advantageous to keep it up to date. Certan is still available from www.beeworks.com in Canada. The Bt aizawai has been used by many for wax moths and there is research on that strain to show it works. I have not used it for about a decade now (I use freezing and timing as it's less work) but have used it in the past. You can spray it on a comb that has wax moth larvae and bees on it and put it back in the hive with no ill effects that I can tell and only beneficial effects as far as wax moths.


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## bevy's honeybees (Apr 21, 2011)

Michael Bush said:


> I have not used it for about a decade now (I use freezing and timing as it's less work) but have used it in the past. You can spray it on a comb that has wax moth larvae and bees on it and put it back in the hive with no ill effects that I can tell and only beneficial effects as far as wax moths.


Thanks for posting this Michael. I have Bt that I got from Sundance but as I'm treatment free now, I haven't used it for 2 years. I freeze the frames and hope for the best, try to keep in shed where it gets some daylight and/or on strong hives. 

The problem I have is when I want to use a frame of brood comb for bait boxes. I've lost more frames to wax moth in bait boxes than anywhere else. 
In this one area I'm going to start using the Bt again without worry, as it is near the time to put out those boxes. Thanks so much!


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## Phoebee (Jan 29, 2014)

Tenbears said:


> Figure 50 ten frame hives all with 2 or 3 supers extracted at season end. I am storing between 1200 and 1500 frames over until put back on the hives. Much easier to mix BT in a 25 gal agra sprayer. give them all a spritz and place them back in the supers. stack the supers and be done with it. I would need 500 storage containers. And I am a small operation.


I guess that depends on the storage containers. I have yet to try it. For my 8-frame mediums I think I can find plastic storage containers (on sale this time of the year) that can probably hold 2 supers worth per box, and they're stackable. I plan to try just sealing the plastic boxes with tape with the CO2 inside. 80% for months ought to be totally effective, and they should stay clean.

The Smithsonian uses plastic tents around objects for their CO2 preservation. Might I suggest some plastic wrap around the frame-filled supers would let you treat whole stacks at once, and you could leave them wrapped for storage. Maybe most of you are happy with Bta, and evidently there are at least a couple of strains that can work if you stay carefully on-label, but I can see this as an option for those interested in going all tree-huggy organic and pesticide free.


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## Rader Sidetrack (Nov 30, 2011)

Phoebee said:


> Maybe most of you are happy with Bta, and evidently there are at least a couple of strains that can work if you stay carefully on-label, but I can see this as an option for those interested in going all tree-huggy organic and [HIGHLIGHT]pesticide free.[/HIGHLIGHT]


Careful now! Carbon dioxide is a _registered pesticide_.  

http://www.epa.gov/pesticides/reregistration/REDs/4019red.pdf
Remember, off-label use of a registered pesticide is a violation of federal law.


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## Phoebee (Jan 29, 2014)

Rader Sidetrack said:


> Careful now! Carbon dioxide is a _registered pesticide_.
> 
> http://www.epa.gov/pesticides/reregistration/REDs/4019red.pdf
> Remember, off-label use of a registered pesticide is a violation of federal law.


Good point. You do, I hope, maintain an MSDS for every compound you use in your business? That used to be part of my job. And I had them for AIR and WATER! Oh, yes, turns out there are MSDSs on them!  

Hey, wait a minute, that says CO2 is GRAS (Generally Recognizes As Safe) and exempt from regulation! And yet, while nitrogen constitutes 80% of air and is merely an asphyxiant, CO2 is actually toxic ... your body produces it but gets rid of it as fast as it can, and relatively low levels will kill. 

Since it looks like I'm about to up my CO2 use from the couple-of-12g-cartridges-a-year level, I thought I'd look at larger cylinders, without going to the big-boys. Turns out they are common in the beverage business, so small cylinders used for carbonating and dispensing your favorite drink are easy to find and refill. Just be clear that this is in the context of making MEAD, right?


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## Michael Bush (Aug 2, 2002)

>Remember, off-label use of a registered pesticide is a violation of federal law.

Is there anything on the label that says I can exhale it?... or is that off label use?...


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## Phoebee (Jan 29, 2014)

Michael Bush said:


> >Remember, off-label use of a registered pesticide is a violation of federal law.
> 
> Is there anything on the label that says I can exhale it?... or is that off label use?...


There must be an agency that issues permits. One would hope you get one with your birth certificate. 

There is a sizeable movement to abolish methane emissions from cattle. This worries me for more than my love of burgers, because if biological methane emissions become illegal, I'm _doomed_.


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## Rader Sidetrack (Nov 30, 2011)

That should not be a big problem - just be sure to carry around a lighter and use it at a ... _judicious moment_.  The end result of methane combustion is effectively carbon dioxide and water.


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## mgstei1 (Jan 11, 2014)

Good old school moth balls or Napthalene is my choice. 1 to 2 balls or a handful of crystals in a stack will do the trick. Keep roaches out too. And I've tried Aromatic Red Cedar shavings also and they work but will not last as long.
Before using the supers or comb, air it in the outside around high noon and they are ready to place in service.

Makes your house and storage shed smell like grandma's house!! Reminds me of mine all the time!!


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## Rader Sidetrack (Nov 30, 2011)

If you want to use mothballs, those made with _paradichlorobenzene _(PDB) are a better choice. A reference from Clemson:
http://www.clemson.edu/extension/beekeepers/publications/wax_moth_ipm.html

.


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## Michael Bush (Aug 2, 2002)

>Good old school moth balls or Napthalene is my choice.

Naphthalene is lipophilic (loves oil) and will permeate the wax. It will also kill bees. It is not an approved treatment (and never has been). The only chemical approved for use on bee combs by the FDA etc. is Paradichlorobenzene. You can find moth crystals that are PDB but you can also find the Naphthalene. I would not use either, but PDB is the only thing you should use if you're going to use chemicals for the wax moths...


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## mgstei1 (Jan 11, 2014)

I use very few chemicals to none at all. Just about anything will kill honey bees. I aint using the mothballs to kill bees just repel moths.
PDB is just as or worse than Napthalene. The vapors disperse in open air and also outa the beeswax or wood in the supers and frames.
I smelled plenty of both in urinals and grandmas house. It works and works well and has for years. 
The FDA has been wrong numerous times and if the truth be known when we smoke bees and combs the smoke most likely has way worse things that soak into the wax and the honey and the bees than a little bit of moth ball vapor. 
Creosote and Turpentine are far worse coming from the smoker. IMHO.


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## squarepeg (Jul 9, 2010)

mr. bush is correct as usual.

"The only chemical treatment currently available for fending off wax moth is PDB (paradichlorobenzene) however; this chemical should not be used on combs filled with honey for consumption. Also, note that this is not the same as using moth balls, which have unsafe chemicals for human consumption and should never be used to treat frames."

from: http://beeinformed.org/2012/07/wax-moth-damage/

both pdb and naph leave a residue in the wax that never disperses and will show up in the honey in varying amounts. best not to use either when there are better alternatives available.

there are a lot of things in beekeeping that 'work and work well' that aren't necessarily good practices.


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## Nabber86 (Apr 15, 2009)

You can get all the Xentari (Bacillus thuringiensis Aizawai) which from Bruce Nyquist at [email protected] (see For Sale forum).


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## Rader Sidetrack (Nov 30, 2011)

The long-running thread in the _For Sale_ forum where _Sundance _offered Bt Aizawai has been marked as deleted and is not readable. I don't think there is currently _any _BT offered in the For Sale forum.


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## VodoBaas1 (Mar 26, 2013)

I found this: http://www.hidhut.com/xentari-p-31.html


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## Michael Bush (Aug 2, 2002)

You could buy it on Amazon, last I looked...


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## BEES4U (Oct 10, 2007)

Thuricide is a trade name for B.t.
Local garden and or nursery shops stock it.


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## Rader Sidetrack (Nov 30, 2011)

Thuricide is the trade name for Bacillus thuringiensis variety _*kurstaki*_:
http://www.southernag.com/docs/labels_msds/Thur.pdf

If you want the _Aizawai _variety normally recommended for comb wax moths, Thuricide is not the same thing.


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## Rusty Hills Farm (Mar 24, 2010)

BEES4U said:


> Thuricide is a trade name for B.t.
> Local garden and or nursery shops stock it.


You need BtA, (Bacillus thuringiensis aizawai) not just Bt. Some types of Bt are actually harmful to bees so it is really, really important to get the right variety. Currently the only version of BtA that I am aware of that is legally sold in the US is Xen-Tari.

HTH

Rusty


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## Michael Bush (Aug 2, 2002)

Amazon seems to be out of stock, but they had some at Christmas time and maybe they will get it back soon:
http://www.amazon.com/gp/product/B004CZ1MOM/ref=oh_details_o05_s00_i00?ie=UTF8&psc=1


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## Kofu (Jan 26, 2011)

Amazon has it right now, and I've ordered a pound, at $40. I'm thinking I can share some with other beeks at cost. ($2.50/1 oz baggie), which ought to last most of us awhile. 

Having read the whole thread and considered the warnings, I'm willing to gamble that it probably won't hurt bee brood that might be the next use of some of that comb. I want to use it on comb for bait hives, and a swarm moving in will want to set up house and raise brood first thing, right? People who've used BTa that way haven't reported any problem as far as I can see. The brood does go through a larval stage, so theoretically they might be susceptible, but it sounds like different bacillus species are fairly specific to certain insect species in their larval stage. 

Also I'm wondering, some say after you spray it on the effect may be good for years. What do people here think, when the bees clean their comb for various uses, and after it's used for storing honey or pollen or for raising brood, would it probably need another dose of BT sprayed on it to keep it protected from wax moths?


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## snapper1d (Apr 8, 2011)

Rader Sidetrack said:


> Thuricide is the trade name for Bacillus thuringiensis variety _*kurstaki*_:
> http://www.southernag.com/docs/labels_msds/Thur.pdf
> 
> If you want the _Aizawai _variety normally recommended for comb wax moths, Thuricide is not the same thing.


I have used Thuricide when I couldnt get Certan which is the aizawai strain.Both are listed to kill the same larvae but I have never seen the kurstaki strain recommended anywhere.I am not saying to use it but I have and it works also.


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## snl (Nov 20, 2009)

Kofu said:


> Also I'm wondering, some say after you spray it on the effect may be good for years. What do people here think


As I'm taking frames out of the extractor (every year) I spray them..... cheap insurance. I've lost frames to expired BT. 
When I find a dead out (before the moths have set in) the frames get sprayed.


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## Phoebee (Jan 29, 2014)

It is interesting to go back to my long post on the first page of this thread, which caused a lot of noise. The linked study from which I got the EPA assessment that Bt alizawi is Bad for Bees has been totally replaced by a benign little posterized dose of pablum of no apparent scientific rigour.

I searched for this article a year or so back, and it seems to have been pulled, with no instances of it anywhere that I can tell.

I do still suggest y'all follow the label directions on this stuff, as for any pesticide. Residue from applying to comb after extraction is evidently harmless. But if it does not say to spray onto live brood comb, don't.

My CO2 experiments took some iterations to get right, but the method is now working. Not saying it is a good solution for most people. Freezing frames is a very good option for many people.


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## Phoebee (Jan 29, 2014)

Kofu said:


> Having read the whole thread and considered the warnings, I'm willing to gamble that it probably won't hurt bee brood that might be the next use of some of that comb. I want to use it on comb for bait hives, and a swarm moving in will want to set up house and raise brood first thing, right? People who've used BTa that way haven't reported any problem as far as I can see. The brood does go through a larval stage, so theoretically they might be susceptible, but it sounds like different bacillus species are fairly specific to certain insect species in their larval stage.


After the wax moths destroyed a swarm trap last year, I decided to try foundationless frames this year, with queen lure and LGO. Good news: no wax moths. Bad news, our favorite queen flew right by it on her way to the woods when she swarmed. And the lures were fresh.

The wax moths from the swarm trap became the test subjects for CO2 fumigation experiments.


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