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

[uglysteve]

This may not be the correct forum for this question, but I'm not sure what is.
 I am trying to grow Cottonwood trees, and bees keep destroying the buds while collecting propolis. How can I stop them without killing them?  My small trees will be covered with dozens of bees. These are the only Poplar trees for miles. I was hoping that they would stop when the mesquite trees were in bloom, bt they continue.
Thanks,
Steve
 


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[Michael Bush]

The primary source of propolis for bees are members of the poplar family.  The buds always produce the waxy substance that the bees most like to collect for propolis.  I have never heard of it causing any damage.  Bees have very weak jaws when it comes to chewing on plant material.  They can't chew through the skin of fruits and have to rely on the wasps to open them up for them to get the juce out.  It seems doubtful that they could do any damage to the buds.  Are you sure?  Bees constantly collect propolis and fortunately for them, poplar trees (and cottonwood trees) constantly provide it.  They rarely use any other source.

[uglysteve]

The new buds are damaged and turn black. When leafs manage to grow, they are deformed and small. I see no other insects on the trees, and I see the bees chewing on the damaged areas all day long. It limits the growing season of the trees to about a month in the early spring, before the bees are active.
I live in the desert, and need my trees to grow fast for shade, and the bees are slowing the progress.
I will try to include a picture.( A picture is now in my first post, thanks to the help of a moderator.)
Thanks in advance for any advice.
Steve

[kathyp]

none of that leaf and chewing damage is from honeybees.   what is that creature to the left?  also, check carefully the underside of leafs for worms and look for aphids.  bees will collect 'honeydew' from aphid excretions.

somewhere on there is a sucking and leaf chewing bug.  honeybees do neither.

[kathyp]

http://www.ipm.ucdavis.edu/PMG/GARDEN/PLANTS/poplrcotnwdaspen.html



http://www.ipm.ucdavis.edu/PMG/GARDEN/PLANTS/DISEASES/baclfblight.html

this site has lots of cottonwood pest info.  this one page show something i have seen in the PNW.  wondered if it looked at all like your tree?

[uglysteve]

I looked for any other insects, none found. No aphids, I don't see ants going to collect honeydew. I have seen aphids on other tree species, but not on my cottonwoods( Freemont and Lance leaf). The aphids seem to only be active in the early spring, may be I just kill them all? This damage occurs from April to September, while the bees are active. I have put Bayer advanced systemic insecticide in the ground. It should spread through the tree, killing anything that actually eats the tree. The leafs don't curl up like there were something sucking the juice from under the leaf, I have seen that on my ash trees. It looks like the bees chew on the buds, causing the leafs to be deformed as they grow.

 I only see the 2 bees in my picture. I was not able to keep everything in focus. From my observations, I see the bees chewing, and the damage follows. I live in the Arizona, may be some killer be Hybred? They don't seem to be aggressive.

I don't mean to sound like I am arguing. I just know what I see.

I appreciate any ideas, advice, or discussion on the matter.
Thank you,
Steve

[uglysteve]

this site has lots of cottonwood pest info.  this one page show something i have seen in the PNW.  wondered if it looked at all like your tree?

Thanks, The blight doesn't look like it. The leafs don't die. It may be possible that the bees are spreading an infection. I will look through that site to see if I can find anything.
Thank you

[buzzbee]

Maybe you have night time feeding insects.Go out with a flashlight after dark,maybe you will discover something else.

[uglysteve]

Good idea, I will look at night. I have seen the Glassy-winged Sharpshooter, in early spring, and they spread Xylella bacterium(Pierce's disease) , according to the University of California web page. I have seen that on various trees, but it doesn't look like the damage the bees appear to be causing.

Thank you everyone, this discussion is helping me find answers to some of my problems.

[kathyp]

also see if you have some experts in your area that know about that particular tree.  they will probably be more help than we have been.  do come back and let us know what you find.  it's interesting.

[MrJeff]

Maybe check with your county extension office. They could have a good idea what is affecting poplars in your area. Or put you in touch with an arborist or some other tree professional.

[uglysteve]

I will try to check with the extension office.
 The Lance leaf cottonwood is not native to this area, I'm in the Superstition mountains of AZ, at 1700 feet. The Lance leaf comes from higher elevations in the rocky mountains. The Freemont cottonwood is native to the area, at slightly higher elevations, along streams.

I think there is a good chance that the bees are spreading an infection.

I would like to know if there is a repelant or pheromone that could be used to keep them away.
Thanks,
Steve

[Michael Bush]

I see a green "leafy looking" insect on the left.

[uglysteve]

I still don't see any insect other than the 2 bees. In the lower left corner is an out of focus leaf. I had to use a 300 mm lens on the macro setting, my aperture had to be open wide in order to make a fast exposure, because of the moving bees. I should try to get some video of the bees in action. They chew the buds. When they have destroyed the buds, they start on the edge of the leaf stem. I don't understand how the bees could not be the cause of the damage. In order to get the propolis resin from the plant, they have to chew the plant.
I e mailed the county agricultural agent, waiting on a responce. I will see if I can get some video, my camera that shoots video is not the best.
Thanks,
Steve
http://yfrog.com/4rbeeoncottonwoodz

http://img171.imageshack.us/img171/4001/beeoncottonwood.mp4

[uglysteve]

Sorry about the poor video quality, thats the best I can get. Thanks moderator for helping me get the video posted.

[Bee Happy]

There's gotta be something else. I don't mean to appear to rush to the bees defense,  but I'm looking at the holes in the leaves, and my gut is telling me that honey bees would not have an interest in feeding on the leaves, these look like attacks from something that eats leaves.

[wd]

I'd be looking more for moths, grasshoppers, caterpillars and the like. Myself, I've never seen a bee eat leafs or buds, they do seem to go after saps, water, juices ect. left as a result of other insects feeding.

[uglysteve]

I will continue to observe the trees.
It looks like the bees chew on the small young buds. When the leafs grow, the damage caused by that chewing, grows with the leaf. Causing holes, and other distortion. The edges of the holes are smooth and rounded over, like some healing took place.The brown spots are burning caused by me spraying the tree with a home made repellent containing water, soap, and garlic oil. It did not work for long. I just noticed that the leaf damage is on new leafs growth with in 4 inches of the end of the branch. The older large leafs closer to the trunk are undamaged. The older leafs grew before the bees were actively on the tree. The bees like to chew the buds on the end of the branch.

If it were moths, worms, or something else, I would think the damage would be more evenly distributed.

I still need to go out at night and look for bugs.  Again, I have the tree full of pesticide. So, I would assume that any insect eating it would die. The bees are not eating, just chewing and collecting the resin. But, I am not an entomologist, so I could be wrong.
I don't want to kill the bees, I need their pollination services.
Steve

[Michael Bush]

>In order to get the propolis resin from the plant, they have to chew the plant.

All poplar trees (cottonwoods, tulip poplars, aspen etc.) produce a wax on the buds that the bees gather.  Bees do not have the chewing parts to chew the plant.  They simply are not built that way.

[wd]

I took some screen shots of your picture posted ... there's another insect in the red circle .. perhaps a grasshopper?

[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.