Pesticide kill in central NC - what are folks spraying???

caticind · October 24, 2011, 11:15:39 AM

Just inspected one of my out-hives (housed with a woman interested in learning about bees) and they are about finished.

Background:

This hive was a June split and had a tough time during the dearth - didn't shut down laying early enough and completely emptied their stores by the end of July. After feeding, they had started to come round and had a burst of foraging activity. I was not impressed with the new queen but felt it would be worth seeing if they made it through the winter. Their host reported seeing lots of activity when the goldenrod and asters were both in bloom but said it had been quiet for about a week. Mite levels consistently below treatment thresholds.

I opened the hive to find even fewer bees than before - maybe 2 frames of bees and the queen. Some capped brood and larvae present but she is not laying much. Maybe 3 full frames of capped stores, and another frame with some open, so they have been finding forage in addition to the sugar they got before. Wax moths beginning to damage outer combs that are still empty. No unusual dead out front, none on that section of the screened bottom.

Then I opened the next lid (this is a long hive, so there is an empty area which bees can access but which is mostly closed off by a follower board). Big pile of dead bees, probably a couple of thousand, definitely more than remained alive.

Most of the dead had clearly been there for several days, a few bees on the top were still alive but immobile except when poked. Neurological? Maybe mortuary bees which were poisoned by contact with the initial kill?

I think it's pretty clear this colony is done, but my main questions are here:

1)What do people treat with or spray at this time of year that foragers would come in contact with?

2) What products kill at the hive rather than on contact, allowing (apparently) most foragers to be recruited to a toxic source?

3)Do any of these products have long half-lives, such that the comb, frames, or woodenware would remain contaminated?

4) What would you do with the hive? With the remaining bees?

Kathyp · October 24, 2011, 11:51:40 AM

at this time of the year, i'd also consider a robbing event. especially with a weak hive. don't know the answer to your other. just another thought...since it's been a problem here....

Hemlock · October 24, 2011, 11:53:02 AM

Quote from: caticind on October 24, 2011, 11:15:39 AM
1)What do people treat with or spray at this time of year that foragers would come in contact with?

2) What products kill at the hive rather than on contact, allowing (apparently) most foragers to be recruited to a toxic source?

3)Do any of these products have long half-lives, such that the comb, frames, or woodenware would remain contaminated?

4) What would you do with the hive? With the remaining bees?

1) Rural = insecticide, crop related (i dont think it's this one). Urban = Any amount of insecticides for any reason (actually anywhere there's a house).

2) Few insecticides kill immediately (Knock down). Most kill quickly enough but not in the few minutes it takes a bee to fly back to the hive and communicate a source of (toxic)water. A insecticide applied to the bees favorite patch of dewy grass can be catastrophic.

3) My guess is that it would have been a sudden event. Not much time for the bees to work it into the wax or store it. BUT! if it was a pesticide I would get rid of the frames. The wooden ware I'd wash big time but keep.

4) Well it doesn't sound good. I wouldn't want to combine those frames in another hive.

Also - Ask if anyone around that property applied any insecticide recently. If someone says they did **Don't Go Off On Them**. That won't help anyone. You likely cant prove it was their application anyway. Discuss with them the issue of bees & insecticides. Ask them to notify you when they plan to apply in the future so you can seal up the bees or move them temporarily.

Plus, get a hold of the county extension agent. Tell them what happened and see what they can or will do for you. They might be able to test the bees for insecticide or locate a recent 'crop' application near the bees. Homeowner applications cant be tracked (yet are usually the culprits). This event harms your ability to keep bees at that location. I would think the county people will look into it.

caticind · October 24, 2011, 12:03:50 PM

To clarify, no signs of robbing. Entrance was reduced to 1/3 since the hive was weak. No dead bees outside, no torn cappings, and both capped and uncapped stores are still present in the hive.

House is in a semi-rural area. A couple of housing developments within 3 miles, but also a haying operation and a forest preserve. Those owning the property and their immediate neighbors are really devoted to organic practices so I strongly doubt they have sprayed. Other neighbors....anyone's guess.

Hemlock · October 24, 2011, 12:12:11 PM

The "haying operation and a forest preserve" sound benign. Take pictures and call the agent.

Hemlock · October 24, 2011, 12:35:03 PM

caticind,

I sent you a PM with info on someone that might help.

AliciaH · October 24, 2011, 01:58:41 PM

I know you said you don't suspect a robbing event, but do you see yellow jackets when examining the hives? Don't underestimate their ability to clean up the dead bodies. It might be why you don't see any.

Good luck, and please let us know what you find out. Losing a hive is always hard.

AliciaH · October 24, 2011, 02:01:33 PM

Oh, I meant to include that many people spray around their houses this time of year to keep the spiders and ants from coming in. Anything sprayed for them would be bad for your bees.

nella · October 24, 2011, 02:19:40 PM

http://www.ncbeekeepers.org/inspect.htm

Maybe a state bee inspector can help you?

caticind · October 24, 2011, 04:57:48 PM

Well, losing this hive is less hard, because they were already weak to the point I thought they would have to be combined this week. The pesticides were just the last nail in the coffin, but I want to learn what I can since I've not encountered this issue before.

The woman who owns the property has seen yellow jackets preying on bees occasionally, and they may have cleaned up some bodies, but she has not seen large-scale fighting, and I do not think they would explain the very large pile of bodies inside the hive, which are still in one piece (no missing heads etc). Not to mention the bees on top which were alive but unable to walk.

I cleaned the empty space in the hive out yesterday, but when the host checked today she said there were more dead bees in the same place (not very many as there are few bees remaining). I will get a sample of the new dead and hopefully the extension officer can test them...