Woolly Beech Aphid – Phyllaphis fagi

Woolly Beech Aphid – Phyllaphisfagi

Common Name: Woolly Beech Aphid

Latin Name:  Phyllaphisfagi


  • Woolly beech aphids overwinter as eggs rather than buds or bark. The eggs hatch at the time the leaves begin to sprout. The earliest persons are referred to as ancestors.
  • The moms are producing young, building colonies at the bag site of the leaves.
  • Some young individuals are born with wings, allowing them to move to other plants.
  • Those aphids with wings also produce young aphids, but only those with attachments.
  • The following generation lacks wings. Both male and female babies are due to be born as fall approaches. Mating can take place, and eggs can be deposited, completing the life cycle.

Host plant: 

This aphid is most commonly seen on European beech (Fagus sylvatica L.) planted in urban or suburban environments.


This aphid is found throughout eastern and western North America, anywhere beech is planted.

Damages caused by Woolly Beech Aphid:

The aphids are entirely coated by white waxy filaments released from their bodies. The woolly beach aphid secretes a large amount of sugar, which causes the leaves to become glossy and sticky. Honeydew, a sweet substance, promotes the formation of a black sooty mold. Ants are frequently drawn to this sugar, and the presence of ants indicates that aphids are not far away. The assault of beech woolly aphids varies yearly, depending on the actual climate of the year. Usually, the damage is not severe and will only be a concern in freshly planted beeches, where development will be slowed. Populations can grow and fall over time, and dead shoots can be detected.

Life history and habits:

The woolly beech aphid overwinters as eggs placed around buds and in bark fissures in fall. The eggs hatch in the spring, a few weeks after the new leaf appears. Aphids are wingless forms that reproduce by generating live young over most of spring and summer. Winged forms emerge mid-summer and fly out in quest of new host plants. These winged woolly beech aphids are similar to glasshouse whitefly or woolly aphid, which are not seen on beech. Up to ten generations of nursery output were reported during one growing season.