I have a fair sized grove of quaking aspen on the north side of our property. The leaves of the aspen and everything below them are coated with a sticky substance on the top side only. It's as if something has been sprayed on them. No noticeable bugs or damage to the leaves. No substance on the underside of the leaves. I don't use chemicals. The area is far away from the road and neighbor, so overspray is not likely. I've looked online and can't find anything. Here's a photo that kind of shows the sticky pattern. Any ideas?
One of our aspen trees has a sticky substance on the leaves. The patio area under the aspen has been covered with this as well. What could this be? S. H., Sandy, UT; 7/16/08
A: The aspens have aphids which secrete sticky "honeydew," and probably are causing the leaves to curl. You can spray the trees with a strong jet of water or insecticidal soap, or you can use a systemic insecticide for control.
I found this. Just googled aspens with stick substance on leaves. What do you think?
Can't you usually see aphids? I'm not seeing any evidence of any creepy crawlies, and the leaves all look OK, no curling or yellowing that I'm noticing. Also weird that whatever it is seems to be dripping down to everything under the trees. Hope whatever it is goes away, these puppies are way too tall to even think about spraying, I'd need a firehose!
Reading through some of the aspen sites, though, it does seem to fit. I wonder how high up in the trees they are - I can try spraying dormant oil this winter, or maybe bring in some ladybugs.
I bet the aphids are on the the newest growth at the top of the tree and the honeydew is dripping down. They are notorious for aphids. I used to tell people to never plant them where you will park or have a patio. The worst I have seen them do is cause an ant infestation seeking the sweet honeydew. Other than spraying them with a firehose, the only option I see is to use a systemic pesticide like bayers tree and shrub care. I would probably just leave them myself. But I'm lazy :)
Live and let live is my usual motto unless a plant is in serious trouble. Everything looks healthy at the moment so I will just hope a bunch of ladybugs discover this nirvana. Funny that I've never noticed this before - we've been here for 32 years and the aspens were well established when we moved in. Hopefully it is just a fluke year.
No visible ants, but on closer inspection I am definitely spying the aphids. I'll just hope for the best. I probably have upwards of a hundred trees clumped together, mostly full-grown with smaller saplings at the edges.