Identifying and Managing Giant Bark Aphids

Large numbers of yellowjackets around a tree often indicate honeydew-producing insects. Giant bark aphids (Longistigma caryae) are a common culprit on oaks.

Signs and Impact

These aphids cluster on woody branches, secreting sticky honeydew that attracts wasps and promotes sooty mold. They rarely seriously harm mature trees.

Simple Control

Blast colonies off branches with a strong jet of water from a hose. This reduces numbers without chemicals.

For more details, see the UF/IFAS publication on giant bark aphids.