Taking action

Prepare for the return of gypsy moths

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

In a few weeks, gypsy moth egg masses will begin hatching in Wisconsin. Property owners interested in reducing gypsy moth populations should consider oiling or removing reachable egg masses well before the hatch begins. Horticultural oils that suffocate the eggs are available at many garden centers and large retailers. In general, these are applied when temperatures are above 40oF and freezing is not imminent. When physically removing egg masses, scrape them into a can of soapy water and then let them soak for a few days before discarding in the trash in order to kill the eggs. Additional management options for homeowners and woodlot owners are available at the Wisconsin gypsy moth website

Gypsy moth egg masses

Gypsy moth egg masses

Property owners looking to hire a business to do insecticide treatments this spring should contact them soon. A list of certified arborists is available on the Wisconsin Arborist Association website. Additional businesses offering insecticide treatments may be found in the phone book under ‘Tree Service.’ Homeowners can also purchase insecticides, some of which are applied as soil drenches, at garden centers and large retailers. For larger areas, a list of for-hire aerial applicators is available on the Wisconsin gypsy moth website.

Although this winter’s cold temperatures in late December and early January most likely did not cause heavy egg mortality, the cold period will still help reduce gypsy moth populations this summer. According to the U.S. Forest Service, temperatures of -20°F lasting from 48 to 72 hours can kill exposed eggs. Eggs that are laid higher up on the bark of trees suffer higher mortality than those located near the ground because snow insulates the eggs from cold temperatures. Fluctuating spring temperatures can also cause heavy egg mortality.

2018 suppression spraying:

Dane County will be the only participant in the DNR gypsy moth suppression program in 2018. Aerial spraying will occur in mid- to late May at seven sites in Madison and one site in Sun Prairie. A total of 485 acres will be sprayed with a bacterial insecticide that affects only small caterpillars. Maps of the sites are available on the Wisconsin gypsy moth website.

Slow-The-Spread treatments announced:

The Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) announced its planned 2018 Slow-The-Spread (STS) gypsy moth treatments in western counties. About 90,000 acres are scheduled for treatment at 36 sites in 14 counties, using low-flying airplanes. Treatments will begin in May and continue through late July or early August, using either bacterial insecticide or pheromones which cause mating disruption.

Map of proposed 2018 gypsy moth aerial treatments.

Proposed 2018 gypsy moth treatments will occur in these counties. Counties in yellow are scheduled for Slow-The-Spread (STS) treatments, while Dane County (in blue) will undergo a suppression spray.

Counties scheduled to receive aerial treatments are: Barron (3 sites covering 2,736 acres); Bayfield (1 site, 787 acres); Buffalo (6 sites, 11,754 acres); Burnett (2 sites, 4,529 acres); Chippewa (4 sites, 12,794 acres); Crawford (4 sites, 5,971 acres); Douglas (1 site, 789 acres); Dunn (5 sites, 43,986 acres); Eau Claire (1 site, 674 acres); Grant (1 site, 497 acres); Green (1 site, 392 acres); Lafayette (2 sites, 527 acres); Rusk (1 site, 463 acres); and Vernon (3 sites, 3,785 acres).

More information on STS treatments may be found online at the DATCP Gypsy Moth website.

Treat your valuable ash trees against emerald ash borer (EAB)

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

Wisconsin homeowners with healthy, valuable ash trees should consider treating the trees with insecticides this spring to protect against emerald ash borer (EAB). The pest is currently the most damaging threat to trees in the state, killing more than 99 percent of the ash trees it infests. 

Infested ash trees have been attacked by woodpeckers looking for larvae to eat.

Infested ash trees have been attacked by woodpeckers looking for larvae to eat.

Woodpecker damage during the winter is often the first visible sign that an ash tree is infested, so it is important to examine your ash trees during cold months when leaves are absent. Now is a good time to consider protection with insecticides: insecticide treatments are usually applied between mid-April and mid-May once leaves begin to return. Treatments on already-infested ash trees are more likely to be successful if the trees exhibit only low or moderate levels of woodpecker damage.

Emerald ash borer has become so widespread that homeowners should consider treating valuable ash trees no matter where they are located in Wisconsin. The highest risk of EAB-infestation is within quarantined counties or within 15 miles of a known infestation. Outside of these high-risk areas, the danger of ash trees becoming infested with EAB is probably lower, but it is widely believed that there are additional, undetected EAB infestations within the state. A map of known EAB infestations can be found at the Wisconsin EAB website.

Location isn’t the only consideration when deciding whether to begin insecticide treatments. For example, such treatments are not economically practical for woodlot ash trees; they would need to be repeated every 1-3 years for the rest of the trees’ lives (frequency of treatments will depend on the product and method used).

What you should do

If EAB has been found locally or if you see any of the signs or symptoms of an EAB infestation in your ash trees, search for information online or seek advice from a tree care professional. You can fund a certified arborist at the Wisconsin Arborist Association’s website. Other businesses also conduct EAB treatments.

Some insecticide products can be applied by homeowners but others must be applied by a certified professional. Review the available options before selecting an insecticide and treatment method. Insecticide information can be found on the Wisconsin EAB website and EAB Information Network website.

Only ash trees need to be protected against EAB. Mountain ash and prickly ash trees do not need protection from EAB because they are not true ash trees and are therefore not attacked by the insect.

Consider the following

  • Determine whether the tree is worth treating. Some ash trees are too heavily infested to save or have structural or health problems that make them poor candidates for insecticide treatment.
  • Trees displaying large amounts of visible woodpecker damage may be too infested to be saved with insecticides. Consult a certified arborist for a professional opinion.
  • Landscape trees improve views, increase property values, provide shade and cooling, and contribute to the quality of life in a neighborhood. Weigh those benefits against the expense of a treatment.
  • Consider the cost of removing or replacing trees. You might be able to treat your ash tree for more than a decade yet still spend less money than it would cost to remove it.
  • The cost of an insecticide treatment will depend on tree size and the product being used. Some products are applied annually; others are applied every two years.
  • Check the credentials and insecticide applicator certification of any business you hire to treat your ash trees.

Signs and symptoms of an infestation

Stay informed and be on the lookout for emerald ash borer. Know where the pest has already been found and look for the signs and symptoms of EAB infestation. Watch ash trees closely for the following:

  • Woodpecker damage (“flecking”) that looks like pieces of bark have been shaved off and removed;
  • Sprouts growing from the base or trunk of the tree;
  • Thinning leaves in the upper canopy;
  • Tiny (1/8 inch), D-shaped exit holes in the bark; and
  • Adult EAB beetles present during the summer.

Ash mortality in Central Wisconsin

Michael Hillstrom, forest health specialist, Fitchburg. michael.hillstrom@wisconsin.gov, 608-513-7690

Forest health has relayed the message over the last few years that stand level ash mortality from emerald ash borer (EAB) is occurring in southeast Wisconsin and along some parts of the Mississippi River. Those areas of mortality continue to progress each year, but stand level mortality is no longer limited to just these areas. 

All the ash in this stand near Roche-A-Cri State Park in Adams County are heavily flecked by woodpeckers feasting on EAB larvae. Extensive flecking indicates EAB has fully infested these trees and mortality is imminent. Photo by Mike Hillstrom.

February and March are good times to look for woodpecker damage to ash trees (known as “flecking”), and potentially find new EAB infestations or expansions of known infestations. Winter scouting has allowed us to detect ash mortality from EAB in unexpected places. I was in Adams County in mid-February looking for EAB biocontrol release sites.  I was shocked to find a stand where all the ash trees were heavily flecked and likely dead or close to it.  We had not previously confirmed EAB in that township or any of the townships directly surrounding it.

This incident further drove home the point for me that even isolated patches of ash are not safe from EAB. We are now past the point of thinking about taking action in ash stands in southern and central Wisconsin; we must now move forward with site assessments, with salvage/pre-salvage harvesting being a high priority for management.  In addition, non-ash regeneration growing should be started sooner rather than later. Of course, in urban settings, now is the time to prophylactically treat high-value ornamental ash trees.

The EAB silviculture guidelines will be revised in 2018; stay tuned.

 

Prepare now – gypsy moth caterpillars return

Gypsy moth caterpillar with distinctive blue and red dots

Gypsy moth caterpillar with distinctive blue and red dots

This June, gypsy moth populations may rise to damaging levels in parts of Wisconsin. High numbers of gypsy moth caterpillars are a tremendous nuisance and can strip trees of their leaves. Combined with other stresses, such as drought or attacks by additional tree pests, this may kill the tree. The insect’s favorite food is oak leaves, but it will feed on many other tree species such as aspen, birch, crabapple and willow. You can take action to reduce the number of caterpillars that will feed on your trees, including placing sticky barrier bands on the susceptible tree species. Continue reading “Prepare now – gypsy moth caterpillars return”

UW-Stevens Point students gain real world skills while helping communities

In an attempt to find an avenue to get small communities in the fold of beginning, or better managing their community tree resources DNR Regional Urban Forestry (UF) Coordinator, Don Kissinger, resurrected memories of his college days when he and his classmates were given a computer simulation to react and manage a fictitious community forestry program. Through this attempt the collaboration with UW- Stevens Point Professor Rich Hauer and his senior level Urban Forestry Lab class began.

Continue reading “UW-Stevens Point students gain real world skills while helping communities”

Amur cork tree is an emerging threat to Wisconsin forests.

Amur cork tree (Phellodendron amurense) is a relatively new invasive plant found in at least four Wisconsin counties. It is classified as Prohibited under Wisconsin’s invasive species law, NR 40. The female cork tree cannot be possessed, transferred, transported or introduced in Wisconsin. We ask that you report this tree to DNR because it is invasive here and in other states and DNR is mounting control efforts before it becomes widespread. DNR works with property owners to achieve this by providing advice, tools and resource opportunities. Continue reading “Amur cork tree is an emerging threat to Wisconsin forests.”

Oil or remove gypsy moth egg masses now

Gypsy moth egg masses are tan colored lumps about the size of a nickel or a quarter. They are usually found on trees but may also be found on outdoor articles such as firewood piles, bird houses and picnic tables.

Gypsy moth egg masses.

Homeowners who are interested in reducing gypsy moth caterpillar numbers this summer should consider oiling or removing reachable egg masses well before the eggs begin hatching in the second half of April. Gypsy moth egg masses are tan-colored lumps about the size of a nickel or quarter, and usually contain 500 to 1,000 eggs. The egg masses can be found on any rough or protected surface including trees, houses, firewood piles, bird houses and other outdoor objects. Do NOT scrape the egg masses onto the ground or step on them or break them apart. Many of the eggs will survive and still hatch.

Continue reading “Oil or remove gypsy moth egg masses now”

Treat your ornamental ash trees for emerald ash borer this spring

A yellow ornamental ash tree at peak fall color. This tree is worth treating to protect it from being killed by emerald ash borer.

High-value ash tree at peak fall color.

March is a good month to consider insecticide treatments for high-value ornamental ash trees this spring. Emerald ash borer (EAB) has been found in 42 Wisconsin counties and is expected to be more than 99% fatal to ash trees that are not protected with insecticide every 1-2 years. Many insecticides used in EAB treatments are applied between mid-April and mid-May, and now is a good time to contact a tree service or other pesticide application business if arranging for professional insecticide treatments.

Property owners with susceptible ash trees should consider a number of factors when deciding to treat their ash trees, including financial cost, tree condition and location, the shade a tree provides, its contribution to property values, and aesthetic view. Homeowners should also consider the financial cost of removing a tree that is killed by EAB, and the benefits that a dead tree no longer provides.

Continue reading “Treat your ornamental ash trees for emerald ash borer this spring”

Finding bird friendly trees

If you are looking for bird friendly trees and shrubs a database has been created that can help. The Audubon Native Plants Database allows you to enter a zip code and get a list of bird friendly native plants. You can filter based on plant type and what type of bird the plant attracts. The database also shows what kind of birds favor particular plants.

 

For more information contact Ellen Clark (EllenA.Clark@Wisconsin.gov), Urban Forestry Communication Specialist, at 608-267-2774.