Q: I found this bug on my rose bush and can’t figure out what it is.

A: Look closely. Do you see those little spikelets on the rear of the green bug?

They’re called cornicles and they are characteristic of aphids. Cornicles secrete defensive liquids; they are excretory in purpose..

This looks like a green peach aphid.

As you may know, aphids harm plants by sucking sap from leaves and stems. If the sap cannot be digested, it is excreted in a sticky syrup called honeydew. Honeydew often coats the leaves and stems nearby. A black sooty mold grows on it, which is unsightly on the plant.

The easiest control is a blast of water. Aphids are not very mobile and a spider or ground beetle would have to have a few for lunch.