Tree cattle are herding up

Howard Russell, Michigan State University Extension, Department of Diagnostic Services - August 07, 2009

Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.

Paul Wylie, CED in Allegan County, sent me some nice photos of some large bark lice (Order: Psocoptera) he observed crawling about on a tree. Paul, whose entomological skills go way beyond modest, identified the bugs as tree cattle, Cerastipsocus venosus. These bark lice are among the biggest of their kind in Michigan. They are usually about 0.125 to just under 0.25 of an inch in length. Their yellow striped abdomens make them quite conspicuous as they move in large herds on the trunks of trees and shrubs feeding molds and fungi that grow on bark. All psocids are characterized by a swollen bump on their faces. Tree cattle are another example of interesting entomological phenomenon and no control measures are needed since they do no harm to the tree.

Here is the herd of tree cattle that Paul Wylie
encountered in southwest Michigan (click on
photo to see larger image). Photo credit: P. Wylie,
MSUE Allegan County.

Here is a nice close up of tree cattle. The
yellow rings on their abdomens make them
easy to identify (click on photo to see larger
image). Photo credit: D. Cappaert, MSU. Courtesy of
forestryimages.org.

Here is what adult tree cattle look like. Pretty
handsome bugs, don’t you think? (Click on
photo to see larger image.) Photo credit: David Cappaert,
MSU. Courtesy of forestryimages.org.

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