Insect

New map illustrates damage from EAB

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

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

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!

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

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

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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Oak health issues in summer 2019

By Mike Hillstrom, forest health specialist, Fitchburg, Michael.Hillstrom@wisconsin.gov, 608-513-7690

The most commonly reported forest health issue in recent weeks has been unhealthy looking oaks. Symptoms ranging from rapid mortality to gradual decline to superficial have been observed on all species of oak this summer.

affected oak tree with dead leaves in lower half of crown

White and bur oaks are being impacted by a variety of health issues in late summer 2019, including fungal leaf infections and bur oak blight. Symptoms are most severe in the lower half of this tree’s canopy. Credit: DNR Forest Health.

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It’s Firewood Awareness Month: do you know what your options are?

By Andrea Diss-Torrance, invasive forest insects program coordinator, Andrea.DissTorrance@wisconsin.gov, 608-516-2223

Most people know that using locally-sourced firewood helps prevent the spread of invasive pests and diseases. What may be less well known are the processes for finding local sources of firewood or learning where and how you can collect it yourself. During Firewood Awareness Month, we want to share what options are out there so you can take steps to protect the places you love.

Firewood isn't dead - infested firewood can carry insects and diseases to new places

Infested firewood can carry invasive insects and diseases to new places. Buy or gather firewood where you will use it or buy firewood that has been certified as heat-treated and free of pests and diseases. Credit: dontmovefirewood.org.

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Red branches on white pine?

By Linda Williams, forest health specialist, Woodruff, Linda.Williams@wisconsin.gov, 920-360-0665

Large white pines with red wilting branch tips may be caused by a very tiny insect called white pine bast scale (Matsucoccus macrocicatrices). The branch mortality that follows may be caused by an insect/disease complex that is still relatively new to Wisconsin.

Branch tips throughout the white pine tree are wilting and turning brown due to white pine bast scale feeding.

Feeding by the white pine bast scale is causing branch tips throughout the tree to wilt and turn red this summer.

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Reports of redheaded pine sawfly colonies

By Linda Williams, forest health specialist, Woodruff, Linda.Williams@wisconsin.gov, 920-360-0665

Colonies of the redheaded pine sawfly have been reported in northeastern Wisconsin. They can cause significant defoliation in some situations and may warrant control if larval populations are large.

This native insect feeds in groups with many sawfly larvae together on a single needle or branch.

This native insect feeds in groups with many sawfly larvae together on a single needle or branch.

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