Tree cattle roaming the range
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.
An
unusual insect that was running around on tree trunks caught the eye of
several folks last week. Norm Myers, MSUE Oceana and Wendy Marek, MSUE
Mason sent me photographs of these small insects that were brought into
their respective county offices. These rather bizarre bugs are large
barklice, commonly known as tree cattle, Cerastipsocus venosus
(Psocoptera: Psocidae). They are called tree cattle because they occur
in large colonies that move about in unison, much like a herd of cattle,
I guess.
Most species of booklice and barklice are very small, almost microscopic
in size. Tree cattle are huge in comparison, reaching nearly a quarter
of an inch long when mature. Psocids are easily identified by their
swollen faces and long antennae. Tree cattle nymphs appear dark gray
with pale yellow banding between abdominal segments. Adults have shiny
black wings that are held tent-like over their abdomens. The term
"lice" as part of the common name of these tree dwellers is quite
misleading as these insects are neither parasitic nor louse-like in
appearance. As scavengers, bark cattle perform a valuable function in
consuming excess accumulations of fungi, algae, dead bark and other
materials that occur on tree trunks and large limbs. Bark cattle do not
eat leaves or the bark of the tree, nor do they damage the tree by
boring into the bark and control measures are not recommended for these
insects.