The nymphs of alder sucker are covered by a ball of fluffy white waxy threads which can make its presence noticeable during the spring. They suck sap from the foliage during April-early June.

The adults, which lack the waxy secretions, are present from June-October. Overwintering eggs are laid on the shoots of alders (Alnus species) in the autumn.

Alder sucker does not usually affect the health of its host and is part of the biodiversity alder trees support.
 

The presence of white waxy deposits can be noticeable in the spring but this insect rarely has any effect on the health of alders. It is part of garden biodiversity and control is undesirable.