How do I keep bees from collecting propolis from my Cottonwood trees?

[uglysteve]

I believe that is a out of focus stem. I have gone over several branches, and can't find any plant eating bugs. I will try and find some fly tape and wrap the trunk, and see what I catch.
Thanks again for the help.
Steve

[wd]

ahem, I looked at the screen shot image I took under a magnification. For what it's worth, it looks a leaf ... Excuse me, should of done that to begin with, before posting. my apologies.

[greenbtree]

Could you plant a small poplar and cover it with a "floating row cover" as a test?  Or you could cover a branch or two on your existing trees.   Floating row cover is a thin fabric cover used in gardening to protect plants from insects.  It lets light and water through.  If you don't see any damage occurring at least you will know the damage is insect based.  If you had a easily opened and closed slit (Close with clothespins or something?) you could even open it at night as a further test.  Just a thought...  I know you can't protect a whole large tree this way.  Other thought is maybe some type of spray that repels but doesn't kill the bees - not sure what would work. A very diluted cedar oil? Or an obnoxious soap like Irish Spring?  You would want to test it on a branch only - one to see if it helps and two to see if it caused damage.

JC

[uglysteve]

I put a mesh bag over the top bud of the central leader of one of the trees.The bud allready has damage. I will see if it recovers and grows. I also looked tonight with a flash light, and did not see any insects. That doesn't mean there are none, I just did not see any.

Once the trees get big, I'm sure the damage won't be a problem, its just while they are small that the damage is a problem.

I tried to make a repelant with garlic, soap, and vegetable oil. Sprayed it on the buds. Worked for a few days only. And caused burned spots on the leafs.

Also, I have planted many species of trees in my yard. 2 species of cottonwood, 4 oak, Ash, sycamore, eucalyptus, apple, pear, peach, orange, guava, pecan, elm, olive, and more.  The cottonwoods are the only trees that have the bees "chewing" the leaf buds, and the only ones to have this type of damage. Some others have had leafs eaten, but it is obviously eaten, and not deformed and distorted.

I put chewing in quotes, because I don't know what else to call it when there mouths are on the plant moving there mandibles open and closed.

Steve

[Michael Bush]

They do use their madibles to collect the propolis and work it, then they put it in their pollen baskets to haul it.

[uglysteve]

The net bags that I put on the buds on the central leader of the tree has kept the bees off, and there is new healthy, fast leaf growth. That tells me it is not an infection, these leafs are coming from a previously damaged area. I have put a bag on a second tree, and will do more as soon as I can get more bags. Will see if the results are repeatable. Still looks like the bees are to blame for the damage.

[Michael Bush]

Anything that keeps bees off will keep other things off.

[uglysteve]

Anything that keeps bees off will keep other things off.

True. I was trying to point out that it is not an infection, that would not be stopped by the bag. I still only see a lot of bees. One got into the bag and died.

[Kathyp]

interesting.  don't think i have ever heard of bee damage to trees.   did you ever get a chance to talk to some tree folks?  wonder if anyone else had notice the same.