Woolly Alder Aphid – Paraprociphilus tessellatus

Woolly Alder Aphid – Paraprociphilustessellatus

Common Name: Woolly Alder Aphid

Latin Name: Paraprociphilustessellatus


  • Woolly alder aphids, Paraprociphilus tessellatus, are most noticeable on the undersides of silver maple leaves in the spring. Maple blight aphids are another name for woolly alder aphids.
  • Woolly alder aphids with a wingspan of 3/8 inch are black to grey.
  • White, fluffy secretion covers the abdomen. Aphids on maple leaves are plump, grey, and wingless, measuring approximately 1/16 inch long and hidden behind dense, white, waxy threads.
  • Wingless aphids on alder have short, thick threads separated into tiny squares. Each egg has a white fuzzy covering on it. Nymphs are similar to wingless adults but smaller.
  • This aphid feeds on sap from the leaves and excretes honeydew, a sweet, sticky liquid that coats lawn furniture, walkways, and ground cover under trees.

Host plant:

Alder and silver maple

Damages caused by Woolly Alder Aphid:


Large, fluffy, white aphid colonies on the leaves or twigs of infested maple trees should be easily identified in May and June. Although their appearance may cause concern, these aphids appear to have little effect. Woolly alder aphids consume a twig. Some infected leaves may droop or fold downward before shriveling and dropping prematurely. This does not affect the vitality of healthy trees. Aphid colonies on the branches and stems of alders do not affect them either.

Life history and habits:

The bug spends the winter as an egg on maple bark or a wool-covered aphid colony on alder. Aphids that have just emerged nestle on the midvein of young maple leaves. These aphids reproduce asexually and form massive colonies. In July, the developing winged generation flies to alder. On alder, several generations may occur, accompanied by the formation of vast volumes of white waxy substance. Some migrants return to the trunk and branches of maple trees to mate and lay eggs, one per aphid. Others continue on the alder as adults.