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diyroofer 08-31-2011 02:33 PM

Pyganic Dust - Yellow Jackets
I have a yellow jacket nest in my wall void. The void the nest is in is small, bordered by a window on top, a wall ac unit on one side, the stud coming down from the window frame on the other and the floor on the bottom. There is no insulation in the void and it is about 14x18". I have checked the attic and the crawl space to see if they had gotten into either location and there is no sign of wasps there. The entry hole (there is only one), is in the cedar shake siding and enters directly into the void the nest is in. I have verified nest location by using a stethoscope on the interior wall. I cannot hear or see anything in the ac unit or in neighboring voids, but there is a ton of activity in the void in question. I have applied Pyganic 1% pyrethrin dust 3 times through the hole in the siding, once 6 days ago, once two days ago and once last night. It seems to have knocked the population back, but there are still many active wasps. My question: do I need to drill a hole into the nest even though the entry hole goes into the same void as the nest? Have I just not waited long enough for full impact? Do I just keep re-applying?

Thanks in advance...

PAbugman 09-01-2011 12:32 PM

The dust you are using is very good for all bees. I suspect that the yjís are going behind the shingle and making a turn, but the dust is not, although it is working to some extent. The nest could be in the void but just above the entry hole, so the dust is mostly going down. Generally one appication of your dust would work in several days at the most. What kind of tool are you using to apply the dust?

Several options:
Keep re-applying until activity stops.
If you can locate the top of the nest, drill into the nest but near the top and apply dust.
Get an aerosol can of insecticide, pretty much any kind but with an applicator tip on it. Work the tip into the void and try to get in past any obstructions and apply heavily. The aero has different physical properties than the dust does and will go places that it doesnít. In a closed void like that you should get a good immediate kill.

Whatever you do, donít seal their entry until no activity for at least several days; otherwise they may chew their way into your house. They will not die passively.

diyroofer 09-01-2011 01:15 PM

Thanks for the reply. I am using the bottle to apply the dust. It is a 10 oz. container with a tapered plastic tip, I cut the tip back so the opening is about 1/16 - 1/8" diameter. I did a trial run into a plastic bag and it "puffed" the dust pretty well. I am putting the tip into the entry hole, the cap behind the tip pretty well seals up against the siding, I am giving it about 3-4 good squeezes (hard) and running. I know it is having some effect cause there are definitely less than there were. However, your guess that the nest is off center from the entry is correct. I can tell by placing the stethoscope on the interior wall that the nest is crammed into a corner:

If I drill a hole into the top of the nest, should I temporarily cover the entry/exit hole, since I will be drilling only 3 or 4 inches away? The void in the diagram is approximately the size originally cited, 14"x18". Thanks again.

EDIT: I should have mentioned that in the diagram there is a stud running down the left side of the void (straight down from the left edge of the window). And the entry hole is actually closer to the left edge of the void than is indicated by the diagram. Additionally, I have taped plastic around the interior of the AC unit and encompassing the wall void. It seems that every time I apply the dust one or two YJs make it into the house but are trapped by the plastic. I have looked in the AC unit from the outside and held the stethoscope up to it on the inside, but there are no signs of activity within the AC unit...thankfully.

PAbugman 09-01-2011 02:59 PM

Donít cover either hole; treat into both; let them enter/exit thru the dust as they wish. Donít forget about the aero idea-that will do things that the dust canít physically do. Treating with both is a good strategy; thatís what I do cause I donít want call-backs for warranty work. Nice diagram.

diyroofer 09-01-2011 05:09 PM

I should clarify that by cover the hole I meant put duct tape over it to buy me 30 seconds or so to drill the hole and treat the drilled hole without getting a face full of yellow jackets. I would immediately remove the tape following drilling and treating. So far I have done all the treatments at night and I haven't even come close to being stung. For one treatment I used a small length of silicone tubing (about 8 inches) in the end of the bottle with the hopes of getting more of the dust applied closer or even onto the nest. That time one yj grabbed onto the tubing and came out with it, but other than that I haven't seen any come out...granted I don't stick around long to look.

So, what would be the argument against temporarily covering the hole for as long as it takes to drill into the void and put some dust in, and then re-opening?

Thanks again for the's been helpful. Is there a specific aerosol you would recommend for a wall void? I am trying to go as low in toxicity to humans/pets as possible, given that i know this space shares some air with inside of my house, my living room actually...and I have a 2 month old and a 2 year old.

PAbugman 09-01-2011 07:45 PM

A temporary patch is fine and sounds like a good idea.

I canít reccommend any aerosols in particular, mainly because Iím not familiar with the over counter aeros. You will be limited in selection because of needing an applicator tip. I donít think many will have that. On the other hand, since you are drilling a hole, then a tip wonít be necessary in the drilled hole. I was referring to using the tip in the original entry. Any kind of aero for crawling insects or flying will work. In a void without insulation the flying insect sprays atomize or fog much better. You probably have some around your house. Flying insect sprays have not residual life, but kill while they are in the air only. Very low in toxicity, but really, all modern day aeros are low in toxicity.

diyroofer 09-02-2011 02:09 AM

Hey thanks again,

I drilled the hole into the nest tonight and it seems to have paid off, I can't hear much at all with the stethoscope on the inside, very light buzzing. Most nights after the treatments they were loud.

I definitely would not have drilled as high as I did had you not mentioned to go for the top of the nest. In hindsight it seems like common sense but I probably would have drilled a lot lower and the treatment would likely not have been as effective (we'll see just how effective it was tomorrow). So thanks for that tip!

I did use a 3 strip wide duct tape barrier over the main entry, it worked great. I guessed as to where the bottom of the window framing stud (x2 just in case) would be and aimed there and about 3 inches left of the AC unit (same perspective as the diagram). I got the drill out and the bottle in quickly, dusted and ran. I went right back, checked to make sure they weren't coming out the drill hole, and pulled the duct tape, and ran again. When I got back to the garage I notice my drill bit had definite larvae/egg goo on it so I am pretty sure I struck gold.

Thanks again for the is appreciated.

PAbugman 09-02-2011 08:38 AM

Iím confident that you got them. IPA is a good celebratory tradition: I have history lessons with Sam Adams.

When you are sure no activity exists, then patch hole. Donít be in a hurry as it has enough residual dust inside that no yjís will return this summer.

diyroofer 09-02-2011 12:33 PM

I watched the nest this morning for about 2-3 minutes before leaving for work. In that amount of time yesterday I would have seen at least 50-100 yellow jackets coming and going and today I saw none! Good news.

I have been planning on ripping that old, decrepit ac unit out of the wall. This will give me a good excuse to do it. I will remove the nest at the same time. I won't have the time to do it for a month, so I will know by then if they are completely done before going in after it.


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