A few years ago, I planted a stand of quaking aspen (Populus tremuloides) trees because I love the way the leaves shimmer in the sunlight. The rustling of the leaves sing a song to me. I couldn't contain my excitement when I first got the trees. The first few years, they would sway uncontrollably in the spring winds. I didn't understand how to anchor them.My knowledge of planting trees was and still remains limited.
Poplar Twig Gall Fly
One day, I noticed spherical protrusions coming out of the leaves. I don't recall ever seeing these bulbous growths on aspens in the Santa Fe National Forest. It makes me sad to learn that the growths are caused by an insect called, the poplar twiggall fly (aka twig gall).
Unfortunately, I haven't been able to find a non-toxic way to eliminate the pests. Please post a comment if you have any ideas.