The mother of all yellow jacket hives...

[MechAg94]

Phosgene gas is also very effective at killing hornets. It's also heavier than air.

Unfortunately, it's also very effective at killing humans and companion animals.

I saw a can of that at the hardware store.  I'll have to try it out.   

A neighboring plant used phosgene as an intermediate chemical.  That can be some nasty stuff. 

[Monkeyleg]

Another method is get a bug zapper, put it as close to the nest as possible, and turn it on. The buzzing noise will infuriate them and they'll just keep swooping in for the kill, and be killed.

But, that's not 100%, and unlike the dry ice, it doesn't sterilize the nest.

Yeah, but it's probably more fun to sit and watch. Deck chair optional.

[280plus]

Yeah, but it's probably more fun to sit and watch. Deck chair optional.

Seconded! 

[AJ Dual]

http://www.harborfreight.com/electronic-fly-swatter-40122.html

Bug zapper and hand-to-hand combat combined.

[Harold Tuttle]

detcord
we need more detcord

[Harold Tuttle]

the HF zapper needs moar power to deal with the exoskeleton on larger insects

[brimic]

A neighboring plant used phosgene as an intermediate chemical.  That can be some nasty stuff. 

I've used the stuff before-at work. Some of the worst stuff I ever worked with I still have access to- Hydrofluoric acid. That stuff would most certainly kill all the hornets, and liquify my bones.

[AJ Dual]

the HF zapper needs moar power to deal with the exoskeleton on larger insects

For complete disintegration? Yes.

However, even a glancing blow maimed even the largest wasps and hornets. They may have been twitching still, but they never got up and flew again.

[zxcvbob]

Get some 10% Sevin dust and toss a generous pinch of it *dry* down the hole at night. (the normal 5% Sevin probably works too.)  Methoxychlor WP is even better.

It will take a few days to get all of them, but they will get it on their feet and track it onto the paper nest and kill the whole hive.  It does NOT knock them out of the air like pyrethrin, so don't say I didn't warn you.  Most of them should be dead or dying by the next day.

[RevDisk]

Yeah, if you go the brake cleaner route, (really more of a field expedient anyway...) don't try to combine that attack with fire. Tri-chlorinated solvents have a habit of decomposing into Phosgene when exposed to heat and flame.

::makes notes::

So, a pile of brake cleaner liberally coated in napalm..?

[Battle Monkey of Zardoz]

Go see your local electric company. My dad used to work for Swepco in E Texas. The carried a spray, and it had a 40 Ft range. Get some if that if the other suggestions fail.

[cassandra and sara's daddy]

shop vac  sucks em right up  a few squirts into the hose after containment and its bye bye

[brimic]

Looks like the hive is mostly dead. There are dead hornets scattered around the opening and I've seen only 2 hornets that were moving today, but they looked like they were hurting.

I might pick up some sevin tomorrow, dump some down the hole, wait a few days, fill the hole and caulk it up. I'd caulk it up now, but I've seen them chew through tougher materials.

[brimic]

::makes notes::

So, a pile of brake cleaner liberally coated in napalm..?

The word 'overkill' doesn't exist in your vocabulary

[Boomhauer]

The word 'overkill' doesn't exist in your vocabulary

When dealing with hornets, particuarly yellowjackets, there is no such thing as overkill.

I usually don't take pleasure in exterminating life. However, I make an exception for hornets and other stinging nasties. They are fun to slaughter.

[MechAg94]

Do you think longer lasting bug killer like that Ortho Home Guard would work?  I figured you could spray it around the crack and then anywhere you can see underneath.  

The only time I have used it against flying insects was against what I called bore bees.  They were bumblebee looking things that made nests in wood.  I've seen them twice, last time at our gun range.  They had bored holes into a couple sections of 2X6 boards.  If you hung around, you could see them go in and out.  They weren't all that agressive, just liked to buzz around and bother you while you were shooting.  The only way I eventually got them was to bring in that Home Guard stuff and spray down the board and in the hole.  I didn't see them after that.  They either died or moved.  Normal wasp spray didn't seem to affect them.
http://doyourownpestcontrol.com/carpenter_bees.htm
I notice this site recommends dusting.

I notice that dirt dobbers seem fairly resistant to a lot of wasp sprays also.

[280plus]

Late but most wholesale electrical, heating and cooling supply houses will have good stuff on the shelf. My favorite is made by calgon and comes in an orange can. Stops em dead. FYI if you hit them or your not sure and they keep flying but like they're drunk, you got em, the drunk ones won't bother you. The worry is the ones that are out while you're treating. They are rarely happy when they return and discover the carnage.