Many species of maples (Acer) show odd shaped galls and blotches on their leaves. These sometimes velvety textured or spindle-like growths are caused by tiny critters called eriophyd mites.

There are several different species which cause different types of growths. These include the maple bladder mite, maple spindle gall mite and some erineum gall mites.

The most common maples infested include silver maples (Acer saccharinum) and red maple (Acer rubrum).

As with most gall forming insects, they feed on the leaf tissue and many lay their eggs in the leaf. These activities result in the plant responding by creating a gall which is somewhat equivalent to a tumor in an animal.

Erineum galls are those that look like a patch of reddish velvet or felt material on the bottom of maple leaves.

As mentioned above, the primary symptoms are the various shaped and colored galls that appear on the leaf. The actual feeding damage done by the insects is very minimal and really does not bother the tree. This is another of those "problems" that is primarily aesthetic in nature.

Since these galls are primarily an aesthetic problem, treatment is rarely, if ever, recommended. In the unusual case where a treatment is considered, the key will be making the proper timing of the application since many of these mites begin to feed pretty much the day the leaf unfolds in the spring. If you are late with the application...it will do no good.

Note: We have provided some general information and observations on this topic aimed at the home gardener. Before you take any serious action in your landscape, check with your state's land grant university's Cooperative Extension Service for the most current, appropriate, localized recommendations.

Types of Insects

"Name That Bug Page"

Note: We have provided some general information and observations on this topic aimed at the home gardener. Before you take any serious action in your landscape, check with your state's land grant university's Cooperative Extension Service for the most current, appropriate, localized recommendations.

 

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