Unusual growth on leaves

woolfie

I have a couple of trees in my backyard with unusual little growths on the leaves. One of the trees is a maple (not either of the two in my other post) and I don't know the name of the other tree.

Here's the pics of the maple leaves. At first I thought it was insect eggs, but I took a leaf off and kept it under observation - nothing hatched and the "things" do look to be part of the leaf.


Other than that, the tree looks otherwise healthy as far as I can tell (although does have a crack in the trunk which sometimes gets flies in it in the Spring, which I treat with a can of Raid):


Here are the leaves of the other tree (what is this tree?!):


Thanks,

woolfie

Brent Ferris

The first tree is almost certainly a Sugar Maple (Acer saccharum). However, if you pull off a leaf, and milky white sap shows at the end of the petiole, it will be Norway Maple (Acer platanoides). The second tree will either be a Linden (such as Tilia europea) or the native Basswood (Tilia americana). If the sun leaves are 3-4 inches in diameter (or larger) and the margin is coarsely serrated it is a basswood; if the leaves are smaller, with fine serrations, it will be a linden, such as little-leaf or big leaf linden or another variety.

The projections on both leaves are galls. The insect in within the projection and feeds from the leaf. Galls are seldom a serious problem for the tree. Heavily infested leaves are dropped and new leaves are grown. The simplest way to control galls is to pick the infested leaves off the tree (only if there are very few infected leaves), or pick up fallen leaves during the year, and infected leaves in the fall. Dispose of the leaves promptly, and you may be able to minimize their effect. IT is more of an aesthetic problem.
Thanks for including good pics.

woolfie

That's really helpful information - thanks!

TreeSpecialist

Galls are abnormal plant growths caused by various organisms -insects, mites, nematodes, fungi, bacteria, and viruses.

The galls in your picutres are commonly called "nipple galls" and can be treated with systemic insecticides.

While no great harm will come to the tree left untreated, the population of the causal critter may flourish only to be even worse the following season.

There appears to be a connection between the health of the tree and the severity of the infestation. Getting the tree into better health may mitigate the problem to a some degree. As a rule, most insect problems are found in unhealthy trees.

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Brent Ferris

TS - you seem to have more info on galls that I am aware of, can I ask your source material?

TreeSpecialist

Sinclair, Lyons, & Johnson - Insects that Feed On Trees & Shrubs , Diseases of Trees & Shrubs - just two of about 150 books on my shelves dealing with trees and tree problems - combined with a degree and 35+ years of experience.

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Brent Ferris

You have an impressive accumulation of knowledge, and obviously an acute ability to find or recall what you need to know. THe library must be very well organized. Where is the degree from?