Thanks to our informed and green-thumbed readers, we know a little more about the sticky mess recently found below many maple trees and about the worms featured in a photo on last week’s Outdoors Page.

The following was offered by our readers:

Norena Guerard

“The culprit in the maple tree mess around town is a tiny insect known as woolly aphids (family Eriosomatdae). They are a very tiny thing which are seen in the air looking almost like snowflakes floating around.

However, they feed on plant tissue withdrawing sap and then excrete a sweet, sticky waste product called honeydew. That’s the sticky stuff that coats anything and everything beneath the trees. (My garden under our trees was a major mess!!) Additionally, on plants, a black fungus called ‘Sooty mold’ can develop — which I also had!”

According to the Minnesota Extension Service, natural biological controls such lacewings, lady beetles, hover flies and parasitic wasps normally keep woolly aphid populations below numbers that heavily damage trees. If the infestation is small and if it is practical, prune out and destroy the infested branches. Insecticides are effective in reducing aphid numbers. Contact insecticides and insecticidal soap are ineffective because they do not penetrate curled leaves or wax. Affected leaves remain curled and distorted even when woolly aphids are successfully managed.

Joan Baron

“Between my neighbor and I we have five trees that every year spit a juice all over the yard, decks and windows. This year was worse than usual. I went on the internet and found it is aphids that is causing this problem. They suck the juice out of the leaves and secret a sticky juice.

We recently cut two of our 50-foot trees down. They recommend Bayer fertilizer/insecticide to rectify the problem.

This is an abbreviated introduction to the mess. My information was gleaned from the University of Minnesota Extension Service website.

I since have found out the aphids are called woolly aphids.”

Ann Holden

“I contacted my nephew in Green Lake, Wis., this morning. He is an arborist. Since we have two maples in our backyard and windows, cars, BBQ and picnic table covered in what appears to be sap, I was very interested in finding out what this stuff is.

After seeing the pictures in the paper and short article on Saturday, I thought I would share with you what I have learned.

First the webs are fall webworms. Here’s an article: http://en.wikipedia.org/wiki/Fall_webworm. Although our maples don’t have the webs I have seen the little white moths in our yard.

Second, the aphid genus periphyllus is what seems to be on the maples. Here’s an article that closely describes the aphids and their honeydew: http://www.ext.colostate.edu/pubs/insect/05511.html. One other thing, my nephew told me that the aphids thrive with the dry, warm weather we’ve been having.

I decided I had enough of the sticky stuff on the windows, etc., and went to work with bug and tar remover. When that left a mess of its own, I tried window cleaner and only made it worse. I mixed ammonia with hot water according to the directions on the back of the ammonia bottle (grandma would have been proud) and the sticky mess was quickly removed.”

 

Tammy Taylor

“My mom was telling me about the story in The Journal about these worms in maple trees. I found some information and think that these worms are called bag worms.”

According to the Minnesota Extension Service, the worms are contained in “bags of silk.” The bags are nearly always filled with caterpillars that crawl on the limbs and eat leaves. The most common culprit is the eastern tent caterpillar, also called the “bag worm.”

Other caterpillars on the trees are forest tent caterpillars or army worms. The two caterpillars look similar, but army worms don’t make the large silk nests. Eastern tent caterpillars rarely leave the tree where the eggs were laid, while army worms crawl over the ground looking for new trees to eat. In a forest, army worms only eat certain trees, such as aspens, while leaving trees like sugar maples alone. Army worms love apple trees. Army worms primarily live in northern Minnesota while eastern tent caterpillars are more common in southern Minnesota. Both are found in sections of central Minnesota.