Top Forestry Pest Concerns
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You can help maintain the natural beauty of Benzie County’s forests by familiarizing yourself with some species of concern and reporting them to the proper authorities. If you have any questions or concerns, please contact Ellie Johnson, District Forester, 231.256.9783 x 268, ellie.johnson@macd.org.
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What is Hemlock Woolly Adelgid?
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Most residents of northern Michigan are familiar with emerald ash borer – an invasive insect that arrived in our state, resulting in the widespread die-off of millions of ash trees. Forests once full of this large, native tree are now stocked with dead snags and state-wide quarantines are still in place preventing the spread of wood material from one place to another. Unfortunately, another invasive species is knocking at our front door, this time targeting a critical habitat species – our hemlocks. The photos emerging from the Appalachian Mountains are stunning. Entire swaths of forest appear to be brown as dense hemlock stands become fatalities to the hemlock woolly adelgid (HWA). Originally from Asia, but now established in the eastern U.S. and moving west, this aphid-like insect can be hard to spot, but they situate themselves at the base of hemlock needles and feed off the trees’ nutrient supply, eventually resulting in mortality. Luckily, unlike with Michigan’s ash trees, this mortality is more gradual – often taking five to ten years. This allows natural resource professionals to work toward saving this crucial hemlock resource. CONTINUE READING MORE>>>
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If you have questions, please contact ISN’s Invasive Species Specialist, Audrey Menninga – 231-941-0960 x18 or email amenninga@gtcd.org.
Oak Wilt Prevention – It’s up to you and me!
Oak wilt, a non-native vascular wilt fungus that is fatal to red oaks, is present and spreading in Northern Michigan. Symptoms of oak wilt include the rapid loss of leaves, typically in mid-summer, and the slow progression from infected red oaks to adjacent healthy red oaks from one year to the next. Oak wilt once established spreads underground through the interconnected root systems of red oak trees. New infections can also begin when beetles spread spores from infected trees to healthy trees that are pruned or injured during the spring and early summer. A newly infected tree will lose all of its leaves in mid-summer.
To help prevent new infections, property owners should refrain from doing any oak removal or pruning between April 15th and July 15th, when beetles move spores from trees killed last year. The Nitidulid “picnic” beetles will pick up fungal spores and transfer them onto a freshly cut oak 1 to 1 ½ miles away. It is critical to not injure any oaks or create any way for the fungus to enter the vascular system of the healthy tree during this time. In addition, it is important not to move any firewood from trees that have been killed by oak wilt because this can also transport the disease to unaffected areas.
Benzie County has several confirmed oak wilt sites and treatment practices are working toward containing the spread. Other surrounding counties have been battling oak wilt since the 1980s, but vigilance is needed everywhere to keep loses from oak wilt to a minimum.
Residential treatment applications can be confounded by underground infrastructure, driveways, walks, gardens, property lines, and many other factors. However, high value residential oaks may be treated with an injected registered chemical that protects individual trees. The treatment needs to be repeated every two years. For homeowners, the injection costs for yard trees might be a viable option. Prevention is far cheaper than treatment.
Oak wilt is here to stay in Michigan. Human activity will most likely move the disease into previously affected stands as time goes on, however, oak wilt can be successfully managed and the oak forest resource will remain a part of our forested landscape.
The DNR and Conservation District Foresters are trying to confirm and document the extent of oak wilt in Michigan. If you would like more information, or suspect you may have oak wilt and would like it confirmed contact the Michigan DNR Forest Health Program at (517) 284-5895 or DNR-FRD-Forest-Health@michigan.gov or the Leelanau, Grand Traverse and Benzie Conservation District Forester, Ellie Johnson at ellie.johnson@macd.org.