New Kind Of Caterpillar Army Invading The Twin Cities

MINNEAPOLIS (WCCO) -- If you've taken a look at the trees in your yard lately, you may have noticed some unwelcome guests. Forest tent caterpillars are making their presence felt.

The caterpillars are mostly found in northern and central Minnesota, but over the past couple years they have begun showing up in the Twin Cities.

Like a silent, but persistent army, forest tent caterpillars aren't picky. They like the leaves of ash, elm, maple, apple and a host of other trees that may be hanging out in your front yard.

"The trick is to catch them when they're relatively small and before they have done much damage," said Jeff Hahn, Extension Entomologist with the University of Minnesota.

Hahn said the two-inch pests can be kept away if they are caught early and if an insecticide like BT is used. If they are left to grow, it's possible they can cause stress to a tree after a couple years, but only if their numbers are great enough.

They can also migrate to the side of a home, but will likely stick around for just a couple days.

"Preventing them from getting on your house, that's another matter and that's going to be tough. You'll just have to kind of live with them for a day or a week until they go away on their own," said Hahn.

In about a month the forest tent caterpillars will begin turning into moths, so you won't see them crawling on trees.

They are also related to the Eastern tent caterpillars that create webs in trees. Eastern tent caterpillar numbers are up in central Minnesota this year.