One species of trees in our neighbourhood seems to be involved in an unusual process. I’m curious to know if it’s a normal or abnormal, healthy or diseased, phenomenon.
What has drawn my attention is the presence on many of those trees’ leaves of multiple, 3 to 4 mm projections growing perpendicular to the plane of the leaf. I’d say that about 30 percent or so of the trees’ leaves are involved, and that when involved, each leaf has from 2 to 15 such projections.
The projections themselves are, as mentioned, 3 to 4 mm long. They seem “plant-like” and fleshy like a soft bud. They look like tiny, tapered, green-purple grains of rice (i.e. very much unlike insect eggs). They cannot be scraped off the surface of the leaf - they seem essentially contiguous with the leaf itself, albeit growing perpindicular to the leaf surface.
The trees so affected seem healthy, but what do I know? The shape of the leaf is a bit like a heart and the veins are pinnate(?).
This seems to affect the box elder trees at my parents place, as well as the oak trees out in our pasture now and again. Family tradition calls it “some kind of bug”, which is the total extent of my knowledge of what causes it.
Anyhow…
It’s been happening at home for at LEAST 20 years (I was probably ten when I first noticed it) and the only trees that have died since have been the elms. You KNOW what killed them
I know exactly what you’re talking about, and you don’t have to worry.
Family tradition calls it “some sort of bug”, which is the extent of my knowledge about it, but the condition has been affecting the trees at the home place for at least 20 years (I was probably 10 when I first noticed this condition) and the only trees that have died in that time were the elms
You didn’t mention what kind of trees you have in your yard, but we have box elders, poplar (aspen) and oak. It seems to affect the box elders the most.
Leaf galls are common on quite a few trees, most notably maples. While they may not look attractive and can even cause a heavily infested leaf to wither, they are not a problem except in appearance. What causes them is a small insect wheich damages the leaf or else lays egges upon the leaf and the leaf builds fleashy “scar tissue” around the problem area to isolate it. To the best of my knowledge, there hasn’t been a tree to die of it or even become severaly weakened and it’s really not a problem worth treating.
