What are the small insects causing the leaves to curl on my cherry tree?

Question:

I’m interested to know about an infestation on our cherry trees. There are colonies of small insects living under the tree leaves which are curling in on themselves. These spots are of interest to ants for some reason. Is this a concern or a normal relationship between the tree, the little black insects and the ants? 

Answer:

Liz Stanley, Horticulture Community Education Assistant  

Those are aphids. The leaves curl and become distorted as the aphids suck the juices out.

The ants are there collecting honeydew from the aphids.  You often find these two insects working together.

They may be black cherry aphids.

Aphids can be controlled by blasting them off with a hose. They can’t get back onto the tree to complete their life cycle.

Here’s more about aphids and their life cycle.

More, including pest management: Growing Fruit Trees in Maine.