Jack pine branch tips killed by the jack pine tip beetle. / Photo Credit: Wisconsin DNR

By Linda Williams, DNR Forest Health specialist, Woodruff
Linda.Williams@wisconsin.gov or 920-360-0665

Jack pine tip beetle (Conopthorus banksianae) is a tiny bark beetle that bores into the twig tips of pines. Damage from jack pine tip beetle was observed this summer on jack pine in Vilas County. In some areas, each tree showed 2-10 dead branch tips in its crown.

Continue reading “Jack Pine Showing Dead, Brown Branch Tips” →

A group of immature bark lice show their characteristic striped abdomens. / Photo Credit: Wisconsin DNR

By Linda Williams, DNR Forest Health specialist, Woodruff
Linda.Williams@wisconsin.gov or 920-360-0665

Barklice, sometimes called tree cattle, tend to congregate in large groups on trees, which can lead some people to worry about tree health. However, they are actually quite harmless.

Immature barklice don’t have wings, so you can see their heavily striped abdomens. Adults have dark-colored wings that form a tent over the abdomen. Both immature and adult barklice congregate in groups.

These insects feed on the algae, lichen and other debris that collects on the surface of tree bark. They do not feed on the tree itself.

Continue reading “Barklice Don’t Damage Trees” →

Neodiprion maurus larvae, feeding on jack pine, are gregarious. Can you spot all five larvae? / Photo Credit: Wisconsin DNR

By Linda Williams, DNR Forest Health specialist, Woodruff
Linda.Williams@wisconsin.gov or 920-360-0665

In mid-July, a few sawfly larvae were found feeding on jack pine in northern Vilas County. After delving into associated literature and reaching out to a sawfly researcher at the University of Kentucky, the sawflies were identified as Neodiprion maurus. There is no official common name for this insect; it is generally referred to as “a sawfly on jack pine.”

These sawflies are gregarious and feed in groups on older needles, doing relatively minimal damage. They are often referred to as “rare” and have been found in Michigan, Minnesota and Wisconsin, as well as Alberta, Manitoba and Saskatchewan in Canada.

Continue reading “Sawflies On Jack Pine Are Neodiprion Maurus” →

Young pink striped oakworm caterpillars feed gregariously on northern red oak leaves. / Photo Credit: Wisconsin DNR

By Linda Williams, DNR Forest Health specialist, Woodruff
Linda.Williams@wisconsin.gov or 920-360-0665

Young larvae of the pink striped oakworm (Anisota virginiensis) have been observed feeding gregariously on northern red oak leaves in Vilas County. Northern red oak is their preferred host, but they can feed on other oaks.

Young caterpillars start life with a shiny black head capsule, but older larvae develop an orange head. Their pinkish body coloration develops as they get older, as well; young caterpillars are dark green in color.

Pink striped oakworm has several fly parasitoids, along with a couple of wasp parasitoids. Populations of pink striped oakworm in Wisconsin don’t usually grow too large or cause problems.

Hollow pitch blisters get darker with age and may resemble cones until closer examination. / Photo Credit: Wisconsin DNR

By Linda Williams, DNR Forest Health specialist, Woodruff
Linda.Williams@wisconsin.gov or 920-360-0665

Northern pitch twig moth (Petrova alhicapitana) is also called the pitch nodule maker or pitch blister moth.

It feeds on branches and twigs of young jack pine and scotch pine, causing a hollow blister of gooey pitch to form around the larvae as it feeds at the base of a lateral branch. It prefers trees that are 20 feet tall or smaller, although it can attack older trees.

Continue reading “Northern Pitch Twig Moth Creates Pitch Blisters On Jack Pine” →