Big infestation of tiny bug on Western New York maple
July 31, 2009
Hi! We’ve got a silver maple tree which is just SWARMED with these tiny bugs with striped abdomens. Each bug is about 1/8″ in length, and they gather in these densely-populated spots which are roughly 8 inches in diameter, and these spots are ALL over the tree. Within each spot are HUNDREDS of the little bugs, and 2 or 3 slightly larger winged bugs, which are a little more ant-like than the little bugs.
So what the heck are they doing? Should I worry about the health of the tree and, conversely, our house since the large tree is right next to our house? We’ve lived here for 12 years, and never seen anything like this.
Worried in WNY
Niagara County, northwest corner of NY state


Dear Worried,
You will need to change your name to “Not Worried” because these Barklice, Cerastipsocus venosus,
are perfectly benign.  Though they congregate in large numbers, they will not harm your tree.  They feed on lichens and not on the tree, though the presence of lichens might be symptomatic of another problem on your tree. Here is what the Texas A&M University Entomology website offers:  “Mouthparts are for chewing. Barklice feed on fungi, algae, dead plant tissues and other debris. Consequently, they are considered harmless and perhaps beneficial to the trees they infest.” We love your scan of these Barklice because most photos we receive show the aggregations.  Your scan shows both the winged adult and the striped immature nymph.

1 thought on “Barklice”

  1. We’ve got these all over our maple tree in western NY State, as well. They are just gross to look at and we don’t even want to go near the tree. Is there anything we can do to get them to move along? Do we need to learn to live with them?


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