The Homeowners Column

The Homeowners Column

On the Lookout for Tree Pests

Photo of Sandra Mason

Sandra Mason
State Master Gardener Coordinator

"It's a small world." This statement is often accompanied with a smirk and chortle when we realize our neighbor's mother was our first grade teacher. We are often surprised that we are just a couple separations from our neighbors, our coworkers, or the waitress at our favorite restaurant. I guess we are surprised since we know plenty of people that have moved to the far corners of the U.S. As Dorothy said in The Wizard of Oz, "My! People come and go so quickly here!" The act of people moving around may seem to have nothing to do with landscapes and natural areas. However as we move around we may inadvertently include lots of hitchhikers; hitchhikers that can become invasive species in our landscapes and forests.

Unfortunately we have plenty of horror stories when it comes to invasive species that arrived in our country as hitchhikers. Fungal tree diseases such as chestnut blight that virtually wiped out American chestnut and Dutch elm disease that decimated American elm trees are just two examples of hitchhiking diseases that forever changed the makeup of our forests and landscapes.

Horrendous hitchhikers have arrived as a part of global shipments in packing materials and pallets. However we can also be responsible if we move firewood long distances. Many insects and fungi can hang out on firewood and that is probably how the plague of ash trees - emerald ash borer - is moving around the country.

We are now on the lookout for a new fungal disease that can infect black walnut (Juglans nigra), a major tree in our forests. It's a disease with an ominous name - thousand cankers disease. It was first detected in several western States as dieback and death of black walnut became more common and severe during the last decade.

As with the other fungal trees diseases mentioned earlier a bark beetle is involved in spreading the fungus. The tiny beetles create numerous galleries beneath the bark of affected black walnut branches, resulting in fungal infection and canker formation. The large numbers of cankers associated with dead branches suggest the disease's name - thousand cankers disease. An infested tree usually dies within 3 years of initial symptoms. The fungus and the beetle have been found east of the Great Plains in Virginia, Tennessee and Pennsylvania. A number of factors suggest that this disease could establish in eastern forests.

Vigilance and quick identification are keys to keeping devastating invasives at bay. University of Illinois Extension is offering a first-detector training program focusing on tree pests on Thursday March 21, 2013 from 9 a.m. to 3 p.m. at the UI Extension auditorium 801 North Country Fair Drive Champaign IL.

This course will provide in-depth training on current and emerging pathogens, insects and plants affecting Illinois trees and forests such as emerald ash borer, thousand canker disease, giant hogweed and Japanese stilt grass. Subjects to be covered in the course include: identification/detection; life cycle/biology; hosts; sampling; management; commonly confused look-alikes; and regulation.

The target audience includes certified arborists, tree care professionals, master gardeners, master naturalists, forestry and natural resource professionals, conservationists, and others with an interest in trees. Continuing Education Units (CEUs) will be available.

Training objectives include: improve first detector training and invasive species awareness; reduce potential risks from pathogens and pests; and increase rapid and affordable plant diagnostic support to tree professionals and tree owners.

Registration is $25; lunch is provided. Fee includes a binder of useful materials and tree drawings (provided by Master Naturalist Jean Burridge) to aid in identifying ash, walnut, or "look-alike" trees. Please register online before March 18. For more information contact me, Sandy Mason at PH: 217.333.7672.

This program is made possible by an Illinois Integrated Pest Management Grant.

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