About this time of year in the spring, when the weather warms up, the blooms are off the stone fruit trees, and the new fruit are just beginning to grow, the ants start to stake their claims on the trees. You can see them marching up the trunks and disappearing into the foliage. What are they doing? Most likely building their scale nurseries. The ants nurse and protect the scale insects, which, tapped into the sap of the tree, produce a sweet nectar that the ants love to eat.
You can pick off the scales one by one (they’re squishy underneath their hardened shells, like baby snails, yes eww gross, wear gloves) but unless you tackle the ants, the scales will just come back.
So, what to do?
The best solution we’ve found is to use a sticky product called Tanglefoot. It’s all natural, no pesticides, perfectly safe, and extremely sticky. Spread some around the trunk of the tree (up a foot or so from the base) and the ants can’t get by. So, they can’t carry the scale nectar back to their nest. Trapped, they can only hang out in the tree and eventually they die.
Just make sure that there isn’t a path into the tree other than the trunk or the ants will find it. And after a while, the tanglefoot will need to be reapplied.