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Check For These And Other Invasives
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June 14, 2018
The Emerald Ash Borer provides a recent and chilling example. The adults are small bullet-shaped, bright green beetles. Larvae are little white caterpillars that eat their way through the living part of the tree under the bark. In their homeland in northern Asia they are controlled, in a "balance" by predators, particularly parasitic wasps — tiny black critters the size of rice grains — who lay their eggs on the EAB larvae and eggs.
From the first discovery in America, in 2002, in the Chicago area, EAB reached the mid-Hudson Valley and Ulster County by 2010. Close to four billion ash trees have been killed by now and EAB is endemic in the Great Lakes region, is spreading across Kentucky, Western Pennsylvania and here. Indeed, despite releases of three species of parasitic wasps, the EAB marches on and is set to kill every ash tree it can reach. Look for the characteristic "D" shaped exit holes left by the larvae on your trees. Ulster towns are taking down ash, because, once dead, they drop dangerous branches all around themselves.
While millions more ash will die, work is going on to find and breed ash that can fight off the EAB. At the same time, the parasitic wasps will establish themselves and provide some bio-control. However, ash, at least for a few decades, will become much less prominent in our forests.
But EAB is only one of a growing cast of horrors. Jumping Worms, from a group of Asian species that were brought here as bait worms, are another threat, and one that could kill your lawn, your flowers, your trees, and rework the entire environment of New York State.
"Earthworms change the environment to suit their needs," says Brad Herrick, ecologist and research program manager at the University of Wisconsin-Madison Arboretum. "When they are introduced, they make a host of physical, chemical and biological changes to the soil environment."
This year, Cornell Cooperative Extension of Ulster County (CCEUC) is offering free identification services for invasive species. If you’re an Ulster County resident and you’ve found a plant, insect or other critter that you suspect may be an invasive, you can take it to the CCEUC office located in the Hannaford Plaza in Kingston. Samples can be dropped off during horticulture hotline hours: Monday, Wednesday, and Friday from 9 a.m. – 12 noon. You may also email a clear photo along with your contact information to [email protected].
Dona Crawford, Master Gardener Coordinator at the Cornell Extension, says, "We’re doing this, because we want to help folks identify. We educate the public, we don’t eradicate stuff ourselves. People want the information and then they can get rid of the problems. Actually, that’s what we do here, we "extend research" from Cornell University to the public."
The Jumping Worms are easy to identify when you dig them up — they’re hyperactive and wriggly. The problem with them is that they devour the leaf litter and everything organic in the upper two inches of the soil. They are described as "massive digesters of soil." When they’re done with your soil, it has very little left in the way of nutrients. It looks like coffee grounds, and plants can’t establish themselves or survive. The result is that lawns and forests change, even die. There are places in the upper Midwest where the forest is changing rapidly as all the leaf litter has gone. In a lawn, the worms eat all the organic material and starve out the grass, while also attracting moles, one of the few species that do well in the presence of the worms. The combination of worm tunnels and mole burrows tends to drain water out of the soil, taking with it even more nutrients. The Asian Jumping Worms can reproduce both sexually and asexually, and their tiny egg cocoons can overwinter in the soil.
John Thompson, Coordinator for CRISP (Catskill Regional Invasive Species Program) says, "The best thing we can do about this is to prevent its spread. That means checking mulch, compost and potted plants for the cocoons or any worms." North America was almost devoid of earthworms after the last Ice Age, and European worms have already changed things, but these Jumping Worms pose an even greater threat. Thompson says, "They’re a major threat to the sugar maple forest in the Catskills."
Meanwhile, Catskill Mountainkeeper is very concerned about hemlock trees, a foundation species for the Catskill forests’ unique ecosystem. "Without the hemlocks," said a Mountainkeeper release, "New York State would be a different place entirely, and right now these amazing trees are threatened by a voracious invasive insect called the Hemlock Woolly Adelgid." For more info, check out their video here: https://bit.ly/2LL4yXi.
Other species that are of particular concern in Ulster county and surrounding areas are Himalayan Balsam, Slender False Brome, Japanese Angelica-tree, Spotted Lanternfly, Hydrilla, and of course, established threats like Barberry and Japanese Knotweed.
On a hopeful note or two, local deer have sussed out that Japanese Knotweed is reasonably tasty (apparently) and chow down on it hard in the spring. If you keep mowing it, cutting, and digging it out, then a "patch" can be eradicated after some years’ of effort. Dona Crawford also reports that the birds have begun to target the Marmorated Stink Bug, and John Thompson notes that woodpeckers are feasting on EAB, not that it saves the trees, but it demonstrates how predators will respond to a new food item.
