Insect

Check your trees for EAB and plan for spring

Posted on by margueriterapp

By Bill McNee, forest health specialist, Oshkosh, bill.mcnee@wisconsin.gov, 920-360-0942

The cold winter months are a great time to think about emerald ash borer and whether ash trees in your yard are suitable for treatment. The pest is currently the most damaging threat to trees in Wisconsin, killing more than 99 percent of the ash trees it infests.

Two side-by-side images depicting different stages of flecking on ash trees - on left side is light flecking in the upper canopy of a tree, on the right side is more severe flecking that extends down the trunk of the tree

Woodpecker flecking is an early sign of EAB infestation when it appears in the tops of trees (left). As the infestation progresses, flecking continues down the trunk and into lower parts of the crown (right).

Continue reading “Check your trees for EAB and plan for spring” →

Protect your trees from disease by pruning when they have no leaves

Posted on by margueriterapp

By Paul Cigan, forest health specialist, Hayward, paul.cigan@wisconsin.gov, 715-416-4920

With the new year upon us, healthy lifestyle habits are sure to be on many people’s minds as they plan for changes in diet and exercise. The new year is also the perfect opportunity to make healthier choices for trees! Winter is the ideal time for tree pruning while avoiding harmful, disease-carrying pests such as the tiny beetles that carry oak wilt from one tree wound to another.

“The best time to prune trees that lose their leaves is during winter when the trees are dormant,” said DNR forest health specialist Paul Cigan. “Not only is it easier to see where pruning is needed when leaves are gone, but disease-carrying pests are inactive due to the cold, making pruning both more effective and less likely to invite unwanted pests.”

While pruning in winter reduces the risk of spread through beetles, Cigan pointed out that the disease can spread year-round in firewood. “Several recent oak wilt finds in northern Wisconsin, including a first-ever find in Forest County, may have been the result of infected firewood brought from areas with oak wilt,” Cigan said. “Keep oak firewood where it is cut for one year, or until the bark is naturally loose, to prevent the spread of oak wilt,” he advised.

For more information, visit DNR webpages for oak wilt and firewood.

Pruning tips

Yard trees and trees in urban settings should be pruned throughout their entire life to maintain strong structure and remove dead wood. Young trees should be pruned to establish a central trunk, proper trunk taper and good branch structure and spacing. Older trees should be pruned to remove dead and/or hazardous limbs. “Pruning should not remove more than 25 percent of the live tree crown, and the lower third of deciduous tree trunks should be free of limbs,” advised DNR urban forestry coordinator Don Kissinger. You can find more detailed, step-by-step tips for tree pruning in this DNR tree pruning publication. 

Certified arborists who offer pruning and other tree care services can be found at waa-isa.org/arborists/search.asp.

2019 Forest Health Annual Report now available

Posted on by margueriterapp

Forest health annual report now available for 2019.

The Forest Health Annual Report summarizes notable impacts for that year of pests, diseases and weather on the health of Wisconsin’s forests. The report is a collaborative product created by DNR forest health specialists from around the state. It outlines the damage and spread of both native and invasive pests and diseases during that year and puts these into context of observations from previous years. Management programs and their results are also described. Highlights from the 2019 annual report include:

  • Dramatically increased decline and mortality from emerald ash borer in southern WI
  • New county and township detections of oak wilt
  • Precipitation record and major storm damage
  • Summary of state nursery studies on Diplodia sapinea, galls on jack pine seedlings, and testing new fumigants to replace methyl bromide

This year’s annual report is available on the DNR forest health homepage. Previous annual reports, including historical reports dating back to 1951, are archived and available upon request. Contact your local forest health specialist if you’d like digital copies of any archived annual reports.

Snow fleas spring to surface in early December

Posted on by margueriterapp

By Todd Lanigan, forest health specialist, Eau Claire. todd.lanigan@wisconsin.gov; 715-210-0150

Snow fleas are a species of springtails that are active during winter and are generally found in groups where their dark-colored bodies stand out against the white snow. While often observed in late winter or early spring, they also come to the surface on warm winter days, making an early December appearance in west central Wisconsin something to note but not altogether unusual given the relatively warm weather in the area. 

Tiny flecks against an impression in snow are hundreds of snow fleas at surface.

Easily mistaken for specks of dirt or debris, snow fleas are tiny soil-dwelling animals that gather on the surface of snow on warm winter and spring days.

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New map illustrates damage from EAB

Posted on by margueriterapp

Forest health staff recently produced a map that highlights a gradient of damage from southeastern to northwestern Wisconsin, which roughly corresponds to the length of time EAB has been present in these parts of the state. Whatever the level of damage, homeowners and landowners should consider treating healthy ash, including trees that have responded well to previous treatments, or removing declining, untreated ash before they become hazardous and even more costly to remove.

County-level map of damage from EAB to ash tree populations in 2019

County-level assessment of damage to ash population by emerald ash borer, 2019.

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Invasive plants, ticks and you

Posted on by margueriterapp

Most people are familiar with the impacts of invasive plants to natural areas, but did you know that invasive plants can be hazardous to human health? Did you also know there is a new app available to learn about tick activity near you and help researchers by recording your own tick encounters?Forested setting with tree in foreground and sign attached to tree that says beware of ticks. Continue reading “Invasive plants, ticks and you” →

Pine wood nematode in Waushara County

Posted on by margueriterapp

By Alex Feltmeyer, forest health specialist, Plover, alexandra.feltmeyer@wisconsin.gov, 715-340-3810

Pine wood nematode (PWN) was recently found to be infecting Scotch pine in Waushara County. Symptoms of pine wood nematode include rapid crown browning (within 3 months) in late summer, rapid drying of wood and presence of blue-stain fungi in the wood.

Row of pine trees with browning needles from pine wood nematode infestation.

Symptomatic trees dying from pine wood nematode. Photo by Alex Feltmeyer. 

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Are you planning to treat your ash trees? If not, stay safe and save money by removing them ASAP!

Posted on by patricialindquist

The emerald ash borer (EAB) will kill nearly all of Wisconsin’s ash trees that are not protected by insecticides. If you have healthy ash trees in your yard, you have an important decision to make: protect your trees with insecticides or have them removed. Either way, time is of the essence. If you delay in treating your ash trees, the treatment may be less effective. And if you wait to remove them, removal costs will be greater and safety hazards will only get worse.

Credit: Joseph O’Brien, USDA Forest Service, Bugwood.org

What makes infested trees so dangerous?

The structural integrity, or strength, of ash branches and tree trunks begins to decline as soon as the tree becomes infested and the wood begins to dry. Lower moisture content increases the risk of branch and trunk breakage, and the timing of breakage is usually unpredictable. Infested trees may also have total trunk failure soon after death, further increasing the chance of dangerous impacts to people and property.

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Dead and dying ash are hunting hazard

Posted on by margueriterapp

By Bill McNee, forest health specialist, Bill.McNee@wisconsin.gov, 920-360-0942 and Andrea Diss-Torrance, invasive forest insects program coordinator, Andrea.DissTorrance@wisconsin.gov, 608-264-9247

Hunters should avoid placing tree stands in or near ash trees, especially in the southern half of Wisconsin, the Mississippi River region and in Door County. Many ash trees in these areas are dead or dying from attack by emerald ash borer (EAB), becoming weaker and more likely to break even with little to no added weight. Continue reading “Dead and dying ash are hunting hazard” →

Look for gypsy moth egg masses

Posted on by margueriterapp

By Bill McNee, DNR forest health specialist, Oshkosh, Bill.McNee@wisconsin.gov, 920-360-0942

Fall is an excellent time to look for and dispose of gypsy moth egg masses that were laid in the summer. Since egg masses usually don’t hatch until April, information gained from fall/winter surveys can be used to avoid gypsy moth damage before the following spring and summer.

Spraying egg masses with oil kills the eggs inside, preventing hundreds of caterpillars from hatching next spring.

Spraying egg masses with oil kills the eggs inside, preventing hundreds of caterpillars from hatching next spring.

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