Parasites on willow sapling.

Parasites on willow sapling.

Observation - Parasites on willow sapling. - UK and Ireland. Description: Planted a willow twig, and 3 years on it`s made progress. These parasites are on it, and by the looks of it they are protected by ants. What are they, and how harmful they are for the tree?

Planted a willow twig, and 3 years on it`s made progress. These parasites are on it, and by the looks of it they are protected by ants. What are they, and how harmful they are for the tree?