Indiana’s forests are reeling from the assault by the emerald ash borer on our ash trees, and now comes another pestilence, threatening our walnut trees.

The Indiana Department of Natural Resources (DNR) has issued an emergency rule banning the transportation of walnut products from nine Western states and Tennessee to prevent the introduction of
Thousand Cankers Disease (TCD), which afflicts black walnut trees and other walnut species, including butternut.

The emergency rule, issued by the DNR Division of Entomology and Plant Pathology, became effective Aug. 30 and will help protect Indiana’s black walnut trees from the disease.

The rule applies to walnut products from Arizona, California, Colorado, Idaho, Nevada, New Mexico, Oregon, Tennessee, Utah and Washington. Banned products originating from or traveling through the affected states include walnut nursery stock, unprocessed walnut lumber or any other walnut material, such as logs, stumps, roots, branches, mulch, wood chips, other products created from walnut trees and hardwood firewood.

Products exempt from the rule include nuts, nut meats, hulls, kiln-dried lumber with squared sides and no bark and finished products such as furniture, instruments, and gun stocks.

Indiana joins Kansas, Michigan, Missouri and Nebraska in banning the transport of walnut products from the infested states. Although TCD has not been found in Indiana, it is a major threat to the state’s black walnut resource. Black walnut is the most valuable tree in Indiana, based on the dollar value of wood produced, mainly walnut veneer, as well as timber and nuts.

There are an estimated 31.5 million walnut trees in Indiana. Approximately 17.7 million board feet of black walnut is harvested annually, with a value of $21.4 million. If all forest walnuts in Indiana were lost because of TCD, it would represent a $1.7 billion loss.

State Forester John Seifert, director of the DNR Division of Forestry, said the estimates do not include the value of urban trees and investments landowners have made for black walnut plantations and tree improvement over the past 30 years.

“We have much to lose from the spread of TCD,” said Phil Marshall, state entomologist and director of the Division of Entomology and Plant Pathology. “It is crucial that we avoid its introduction into Indiana. The rule essentially protects our state, allowing us to prevent potentially infected material from entering Indiana.”

Forest landowners do not need to harvest or cut their black walnut trees as a result of the disease or the emergency rule. If you notice a suspicious decline in black walnut trees or otherwise suspect an infestation of TCD, call 866-NO-EXOTIC (663-9684).

If approached by individuals offering to cut a black walnut because of the disease, contact the DNR or a consulting forester to have the tree checked for disease.

Also, according to The Associated Press, Tennessee agriculture officials are now expanding an emergency quarantine for TCD beyond Knox County, to several other counties in the state. The emergency quarantine has been expanded to Anderson, Blount and Union counties due to new discoveries of the disease.

There are also restrictions on moving walnut products and hardwood firewood in Campbell, Claiborne, Grainger, Jefferson, Loudon, Monroe, Morgan, Roane, Scott and Sevier counties in Tennessee. The disease was first discovered in Knox County last month.

Originally found in Arizona, TCD affects many types of walnut trees to varying degrees, but is lethal to black walnuts, which often are grown in plantations in Indiana but are also commonly found in the state’s urban and rural forests.

TCD is spread by walnut twig beetles carrying a newly identified fungus. Smaller than a pinhead, the beetles bore into walnut branches, feeding on the tree’s tissues and depositing the fungus which creates a canker, or dead area, under the bark. Multiple feedings cause the formation of thousands of cankers under the bark and destroys the tree’s ability to transport water and nutrients.

Gradually, branches die, and then the entire tree. Walnut trees affected by the disease typically die within two to three years after symptoms are noticed.

“It is amazing that this much destruction could come from such a tiny beetle,” Marshall said. “The walnut twig beetle is just the latest invasive pest to threaten Indiana’s forests and our $8 billion timber industry. Indiana already has issues with the gypsy moth and emerald ash borer.

“It’s fairly simple: To preserve our forests, people must not bring destructive insects and diseases into Indiana, and we need to do our best to inform the public and take management steps to protect our forests.”

More information on TCD can be found online at www.dnr.IN.gov/entomolo or at www.ppdl.purdue.edu/PPDL/current _interest.html#WTCD

Timber industry businesses needing assistance with the rule should contact the Division of Entomology and Plant Pathology at 317-232-4120.

DNR biologists studying lake fish populations
To better understand how fish populations and fishing conditions change from year to year, the DNR Division of Fish and Wildlife (DFW) began a series of surveys this summer at five natural lakes in northern Indiana. The surveys are designed to track annual changes in number, size, weight and growth of various fish species in each lake over the next five years.

Lakes selected include 308-acre Adams Lake in LaGrange County, 206-acre Crooked Lake in Whitley County, 32-acre McClure Lake in southern Kosciusko County, 22-acre Mud Lake in Fulton County and 187-acre Waubee Lake in northern Kosciusko County.

The lakes were chosen because they represent a variety of lake sizes, habitat conditions and fish communities.

“We know fishing fluctuates from year to year, but we don’t know the magnitude of the changes or reasons for the changes,” said Steve Donabauer, DFW assistant fisheries biologist and coordinator of the project. “We also don’t know how lakes change through time and how factors such as habitat damage, watershed management practices and climate may affect fishing.”

Donabauer labeled the five lakes as “fixed sites” because they will be monitored annually; however, DFW biologists will also sample 11 other natural lakes chosen at random each year. A variety of information will be gathered at each.

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