Stinkbugs enjoy an invasive tree - and hitchhiking
"Heavy infestations seem to be associated with fields with wooded borders, especially if there are concentrations of the invasive weed Tree of Heaven," Herbert said. "Both are native to China and the (stink bug) seems to be strongly attracted to that host, especially when the trees are putting out their seed clusters. It's like a happy reunion."
The highest concentrations of the stink bugs have been found where the invasive plant is also found in high numbers, Herbert noted.
The Tree of Heaven, scientific name Ailanthus altissima, is also known as China-sumac, Paradise Tree, varnishtree and stinktree, was introduced to the United States around 1748 by a Pennsylvania gardener and has spread throughout the states.
For a time, the up to 80-foot tree was even sold commercially, and it is now prevalent in 42 states and is the most common non-native tree in the Shenandoah National Park, according to the park service.
"I have not seen any (area) farms that don't have that tree on it," Rockingham County agriculture extension agent Matt Yancey said. "It's gotten out of hand and become very problematic as an invasive."
It produces a toxin in its leaves and bark that inhibits the growth of other plants, and grows and spreads rapidly, Yancey said. It can survive in the harshest of conditions and is probably best known as the species of tree referenced in Betty Smith's famous novel, "A Tree Grows in Brooklyn."
"It's displaced a huge amount of our native trees," he said. "Most farmers I don't think are aware that control of the tree is possible over winter, and with the stink bugs (using it as a host) that's just another great reason to kill this tree."
While the tree's best use is as firewood, Yancey said, it resprouts vigorously when cut.
"Cutting is not a good idea if you don't immediately apply an herbicide to the base or stem," he said.
Herbicides containing triclopyr are effective if used immediately after cutting a tree down, and they are available for general use at many area retailers.
"You can do it in the dead of winter," Yancey said. "As long as the ground is not frozen and there's no snow on the ground."
The tree is identifiable during the winter months by large, thumb-nail size scars on the branches left from fallen leaves. It also, like the bug, is armed with a pungent aroma to ward off predators.
"People say it's like a rancid peanut butter or cashew smell," Yancey said. "I don't know what rancid peanut butter smells like, but (the tree) is pretty nasty."
Taking the trees out now, might help ward off the stink bugs later, Yancey and Herbert agreed.
"It's not an uncontrollable problem," Herbert said. "Taking out the Tree of Heaven will certainly help.
"There's no doubt (the stink bugs) like that tree."
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