By Linda Williams, Forest Health Specialist, Woodruff;
Linda.Williams@wisconsin.gov, 920-360-0665
What can learn new things, move toward and acquire food, remember where food was and what foods are preferred, figure out the shortest route through a maze, remember where it has traveled and seem to disappear as quickly as it first appeared?
It’s slime mold, of course!
By Michael Hillstrom, Forest Health Specialist, Fitchburg; Michael.Hillstrom@wisconsin.gov
Caterpillars wandering the snow in February? Yes, the “winter cutworm,” Noctua pronuba, is a hardy species that is sometimes observed active in temperatures as low as the 20s.
By Paul Cigan, DNR Forest Health Specialist, Hayward;
https://dnr.wisconsin.gov/topic/foresthealth/staff, 715-416-4920
This winter, the spread and impact of emerald ash borer (EAB) have been confirmed in several new northern townships in previously invaded counties.
These include Marengo (Ashland County); Gordon, Hawthorne and Oakland (Douglas County); Cadott and Colburn (Chippewa County) and Balsam Lake and St. Croix Falls (in Polk County).
Continue reading “Emerald Ash Borer Spreads Through The North”
By Linda Williams, Forest Health Specialist, Woodruff;
Linda.Williams@wisconsin.gov, 920-360-0665
Have you ever wondered just how much sap can be sucked out of a tree by aphids?
Aphids insert their piercing, sucking mouthparts into needles, twigs or bark, depending on the species of aphid.
Once their mouthparts are inserted, they begin to suck sap and will excrete excess moisture as small droplets of water called honeydew.
By Bill McNee, DNR Forest Health Specialist, Oshkosh;
Bill.McNee@wisconsin.gov or 920-360-0942
Numerous tan-colored spongy moth egg masses on a bur oak in Walworth County. / Photo Credit: Bill McNee, Wisconsin DNR
The Wisconsin Department of Natural Resources (DNR) encourages property owners to examine their trees for spongy moth egg masses and determine whether control measures are needed this spring.
Spongy moths thrive in warm and dry weather. Even if weather conditions are more typical this spring and summer, the current spongy moth outbreak — which defoliated a state-record total of 373,000 acres of woodland last year — will likely continue and spread.
By Linda Williams, DNR Forest Health Specialist, Woodruff;
Linda.Williams@wisconsin.gov or 920-360-0665
Squirrels have stripped off the bark of this maple tree to get at the sweet cambium layer under the bark. / Photo Credit: Linda Williams, Wisconsin DNR
Typically in the spring, squirrels can cause damage to maple trees by removing bark from branches and the main stem after the trees have been frozen all winter and the weather starts to warm up. This fall, before the January cold spell, temperatures had warmed up by mid-November and remained warm throughout December.
As a result, starting in late November fresh squirrel damage was being noted on some scattered maples in north central Wisconsin. Damage progressed throughout December and some trees have more than half of the bark removed from branches and the main stem. The sight of scattered bits of bark around the base of these trees is another sign of squirrel activity.
Continue reading “Squirrel Damage To Maple Trees Showing Up Earlier This Winter”
By Bill McNee; DNR Forest Health specialist, Oshkosh;
Bill.McNee@wisconsin.gov or 920-360-0942
Woodpecker damage is an early sign an ash tree might be infested with emerald ash borer. / Photo Credit: Wisconsin DNR
The Wisconsin Department of Natural Resources (DNR) encourages property owners to watch for woodpecker damage to their ash trees this winter. If damage is found, property owners should make plans to take action in the spring.
Woodpecker damage, often called “flecking,” happens when birds peck away some of a tree’s bark to access the larvae underneath. Flecking is a common early sign that an ash tree might be infested with emerald ash borer (EAB), an invasive insect. EAB is the most damaging threat to Wisconsin trees, killing more than 99% of the untreated ash trees it infests.
Continue reading “Woodpecker Damage On Ash Trees May Indicate Emerald Ash Borer”
An aspen leaf that fell in the fall showing a “green island” due to leafminer feeding. / Photo Credit: Linda Williams, Wisconsin DNR
By Linda Williams, DNR Forest Health Specialist, Woodruff;
Linda.Williams@wisconsin.gov or 920-360-0665
Most aspen leaves that fell this fall were a beautiful yellow gold color, but every so often some could be found that were yellow with a green strip on them. Were the aspen trees supporting the Green Bay Packers? No. The green stripe was an indication of the presence of a tiny leafmining caterpillar.
Leafminers are tiny caterpillars that live and feed within a leaf. These tiny caterpillars may produce blotch mines or serpentine mines that create lines on the leaf.
Continue reading “Leafminer Creates Green Bay Packers Colors On Aspen Leaves”
By Linda Williams, DNR Forest Health Specialist, Woodruff;
Linda.Williams@wisconsin.gov or 920-360-0665
Bronze birch borer has attacked these trees, and parts of the tree above the attack site are thin and declining. / Photo Credit: Linda Williams, Wisconsin DNR
Bronze birch borer (Agrilus anxius) is a native beetle that attacks birch trees. As adults emerge from the bark, they create small, D-shaped exit holes, similar to emerald ash borer but smaller.
Bronze birch borer attacks stressed trees, and the source of the stress can be anything from drought, flooding, defoliation or old age.
Continue reading “Bronze Birch Borer Attacks Stressed Birch”
Locations of known moderate or high beech scale populations as of November 2023 are shown in red. High populations are known to be widespread in Door County. / Map Credit: Bill McNee, Wisconsin DNR
By Bill McNee, DNR Forest Health Specialist, Oshkosh;
bill.mcnee@wisconsin.gov or 920-360-0942
Earlier this year, we reported that high populations of the non-native insect beech scale (Cryptococcus fagisuga) were identified for the first time in Marinette and Sheboygan counties. Since then, several more sites with moderate or high scale populations have been identified (see map).
Continue reading “Please Report Beech Scale Outside Of Door County”
