Beetles making difference in woolly adelgid fight

By David Singleton
A beetle is winning the battle against the hemlock woolly adelgid at Nay Aug Gorge.

Almost 20 years after the woolly adelgid arrived at Nay Aug Park and started threatening the hemlocks in and around the gorge, officials believe they’ve finally gained the upper hand against the invasive, tree-killing pest, thanks in large part to a predatory beetle called S. tsugae.

“I think we caught it in time, and we have turned the corner. There is no doubt about it,” city forester Tony Santoli said. “I have seen great improvement.”

Since it started working with Santoli in 2011, Tree-Savers, a private company with offices in Waymart that specializes in saving endangered hemlocks, has released about 10,000 S. tsugae beetles at Nay Aug as part of an effort to eradicate the woolly adelgid and restore the park’s weakened hemlocks to health.

Like the woolly adelgid, the beetle — its full scientific name is Sasajiscymnus tsugae — is native to Japan. It is the woolly adelgid’s natural enemy, feeding on the tiny insect’s eggs.

A beetle is winning the battle against the hemlock woolly adelgid at Nay Aug Gorge.

Source: Beetles making difference in woolly adelgid fight at Nay Aug Park – The Times-Tribune, 2017-04-15

Research links decline in hemlock forests to changes in water resources

An insect infestation that is killing hemlock trees in New England forests is having a significant impact on the water resources of forested ecosystems that provide essential water supplies to one of the nation’s most populous regions, according to research by Indiana University geographers and colleagues at three universities in Massachusetts.

The study is the first to show an increase in water yield—the amount of water reaching streams and rivers—resulting from forest damage caused by an insect pest called the hemlock woolly adelgid. Insect-damaged trees use less rainfall and allow more water to reach the ground and run off into waterways. With less foliage, the trees return less moisture to the atmosphere via transpiration and evaporation.
“We observed a 15 percent increase in annual water yield,” said Taehee Hwang, an assistant professor in the Department of Geography in the IU Bloomington College of Arts and Sciences. “But there are a lot of issues involved with this subject. Water quality may suffer as rainfall runs off more quickly from forested areas and carries higher concentrations of nutrients. The long-term picture may change as hemlocks are replaced with broad-leaved trees that have a different impact on water resources.”

Source: Research links decline in hemlock forests to changes in water resources – Phys.org, 2017-04-05

Climate change strengthens an army of forest-eating insects

By Rowena Lindsay
Hemlock woolly adelgids aren’t native to North America, but droves of them have settled into American forests where they threaten entire ecosystems.

A tiny bug, no bigger than a grain of pepper, is wreaking big-time havoc in US forests, and forest managers are scrambling to keep up.

Hemlock woolly adelgids aren’t native to North America, but droves of them have taken up residence in hemlock forests, from New England to the West Coast, thanks to increased trade and travel. Nestled under the needles of hemlock trees, the invasive insects cut off nutrients to the tree and can eventually take down trees that have stood for 300 years.

If left unchecked, the hemlock woolly adelgid and other pests are projected to put 63 percent of the nation’s forests at risk by 2027, according to a study published this year in the journal Ecological Applications. The tiny invaders could put several species of hemlock at risk for extinction, threatening the biodiversity and stability of ecosystems across the country and cutting a carbon sink for mitigating greenhouse gas emissions.

Globalization has opened the door for hundreds of invasive pests, from the Asian longhorned beetle to the emerald ash borer. And climate change, it seems, will make it even more difficult to evict them.

Source: Climate change strengthens an army of forest-eating insects – CSMonitor.com