Barklice are beneficial insects

Q: What are these black bugs on my sugar maple tree? Should I kill them or are they harmless?

A: There are several common names for these harmless creatures. I like “tree cattle” and “tree maids” but the most common name is “barklice”. Despite the name, they are neither parasitic nor louse-like in appearance. Their scientific name is Cerastipsocus venosus.

A close insect cousin, Archipsocus nomas, is smaller and often the colony will cover itself in a continuous silver web.

Entomologists count them both as beneficial insects. They perform a valuable function in consuming excess accumulations of fungi, algae, dead bark and other materials that occur on tree trunks and large limbs. In effect, they function as maids to help clean the bark of undesirable inhabitants.

Barklice do not eat leaves or the bark of the tree, nor do they damage the tree by boring into the bark.

No control measures are recommended for these insects as the barklice are providing a beneficial service by helping Mother Nature to keep the bark clean and tidy!

Tree cattle are harmless

Beneficial barklice

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