Tuesday, December 11, 2012

Horribly ugly beetle threatens Ohio's important walnut trees

If the threat to the nation’s various tree species from a host of new pests continues maybe the only green things left will be invasive plants themselves.

You know: Multi-floral rose and kudzu, along with such hardy native - but noxious - plant species as poison ivy.

In a joint electronic press release,the Ohio departments of agriculture and natural resources report that the walnut twig beetle has entered the state.

Specifically, eight walnut twig beetles were discovered in Butler County, which is located in extreme southwest Ohio.

The walnut twig beetle is believed to be a native species to the country, being first recorded in 1928 in New Mexico, says an agricultural bulletin from Purdue University.

While the beetle itself isn’t the root cause of walnut tree death, the “bug” is a vector for a fungus that does the dirty work. This fungus causes Thousand Cankers Disease (TCD), a presumed always-fatal disease for the walnut tree.

Walnut, of course, is a commercially important hardwood that is used extensively in a host of products.

For sportsmen that includes as material for firearms’ stocks and handgun grips.

Just how important walnut is to the making of high-quality stocks for rifles and shotguns can be seen in Henry Repeating Arms Company advertisements. The gun maker boasts of using Ohio-grown walnut for its stocks.

And the British auto firm Jaguar creates mind-bending beautiful car dash boards out of American black walnut.

As for the health benefits of eating walnut meat, the fruit is high in vitamin C, is useful in the treatment of heartburn, colic and dysentery, and is said to even aid in preventing impotency, says on-linefamilydoctor.com.

Clearly then the threat from TCD is real and the death of an infected tree is hardly pretty, either.

The Purdue document further goes on to say: “During the final stages large areas of foliage may rapidly wilt.

“Trees often are killed within three years after initial symptoms are noted.

“Tree mortality is the result of attack by the walnut twig beetle (Pityophthorus juglandis) and subsequent canker development around beetle galleries caused by a fungal associate (Geosmithia sp.) of the beetle.

“A second fungus (Fusarium solani) is also associated with canker formation on the trunk and scaffold branches.”

Since its 1928 discovery, the repulsively ugly, tiny beetle (smaller than the point of a lead pencil, or about the size of a black pepper grain) has appeared in several other states, nearly all of them in the West.

Here, entire groves of walnut trees have been decimated.

And because the beetle is considered a very weak flier the mode of transportation is generally thought to come from the movement of walnut lumber and similar products.

In September, Ohio’s agricultural department enacted an exterior state quarantine regulating the transportation of walnut products from areas of the 12 affected states.

“Although TCD has not yet been detected in Ohio, landowners and homeowners are strongly encouraged to watch for signs of TCD on their walnut trees,” the Ohio joint communiqué says.

State officials are surveying the Butler County area for beetles, as well as surveying walnut trees for signs of TCD.

After further investigation, officials will determine an appropriate course of action, the two Ohio state bodies say.

- Jeffrey L. Frischkorn
Twitter: @Fieldkorn

No comments:

Post a Comment