Question
Hi,
We planted 5 white pines last October each about 6ft tall.
We just noticed that three of the five have black ants - a lot of ants all over them.  Can you tell us if this is a problem and if so what we can do about it please?
Thanks,
Cliff

Answer
More than likely there are insects that suck the plant juices from the plant on the trees. It would be either aphids or scales. These insects suck the juices and secrete a substance called honeydew which is high in sugar content. This is what the ants are after. Ants actually "farm" the aphids and harvest the honeydew, Kill the aphids and the ants will go away. The white pine aphid (Cinara strobi) is regularly noted on eastern white pine in Iowa. Cinara aphids are often tended by ants, which feed on the honeydew and protect the ants from natural enemies.

Traditional insecticides used in the home landscape for aphid control on conifers include Isotox, Malathion, and Sevin.
Spray the foliage and repeat in 7-10 days for three applications. This will control the aphids and the ant problem. Check with your local nursery/garden type store for an insecticide for aphids on trees.