No one is playing pranks and putting plastic shrink-wrap around trees, although it may look like it in one Kansas county.

For the first time in years, webbing, which has been described by some as looking a bit like pantyhose, has been reported in Shawnee County, according to Bob Bauernfeind, horticultural entomologist with Kansas State University Research and Extension. Shawnee County borders Douglas County on the west.

The web formation is caused by larvae of the Gretchena consitatricana, unofficially named the black walnut shoot moth or the walnut trunk webbing moth. Outbreaks of the insect are sporadic, and little is known about its seasonal life history, Bauernfeind said. The strange webbing encases the trunk and large branches of walnut trees. It is thick and in sunlight gives the encased trees a shimmery appearance.

“Intense webbing appears to be associated with large established trees growing in woodland areas,” he said. “These trees would be capable of supporting the tremendous population of larvae.”

Webbing is the after-the-fact artifact of extreme larval populations. It’s formed as mature larvae travel down to the ground, where they seek shelter in the soil to pupate.