It was a brisk, cold November morning when the volunteers met at the top of the trailhead that leads down the steep ravine to the Plotterkill treatment site. Around 250 trees were scheduled to be treated with the tree-saving, insect-killing mixture of imidacloprid and dinotefuran; one for immediate knockdown of adelgid present in the tree, one for long-lasting protection from the invasive insect that has wreaked havoc on hemlock populations up and down the East Coast. DEC applicators were there in Plotterkill that day to fight this pest along the edge of the currently known populations in New York, a line that passes through the middle of the Capital-Mohawk PRISM (Partnership for Regional Invasive Species Management) region.
Hemlock Wooly Adelgid is a tree pest that has been found as far south as Georgia and as far north as Maine, showing up in stands of iconic Eastern Hemlock. In New York, it finally reached the stronghold of this tree, the Adirondacks, earlier this year. The DEC did a rapid response treatment of that site at Prospect Mountain with APIPP, the Adirondack PRISM Partner group hosted by the Nature Conservancy and then used the knowledge that they gained through that treatment to quickly respond to another new discovery of adelgid at Plotterkill Preserve in Rotterdam. The treatment had been planned for a few weeks earlier, but due to changing weather conditions, it had been delayed until November, one of the last times available before it became too cold for the chemical treatment to work effectively. Just in time, applicators, Capital-Mohawk PRISM staff members and volunteers from the Schenectady County Invasive Species (SCIC) Committee descended on the site for two days, treating as many trees as possible to preserve the future of the Eastern Hemlock in Schenectady County.
Many homeowners and forest owners love their hemlocks, for their innate value, their attractive evergreen foliage, and the ecosystem services they provide. The trees themselves hold stream banks in place, shading the cool waters to provide habitat for many species. In places that have been particularly hard-hit by this insect, hemlocks have died back clearing habitat for invasive plant species such as Japanese Angelica Tree and more well-known invasives such as barberry and bush honeysuckle to take root. There are a variety of at-home treatments that can be used to protect standing hemlock trees, but how do you know if you have a problem in the first place? For one, it’s likely that if your trees are in a location near where Hemlock Wooly Adelgid has been previously found, preventative measures are likely to help ensure their survival. Another indicator of adelgid presence is the wool that is their namesake, which will show on the bottom of hemlock branches.
If you have found HWA in a new location you can contact your regional PRISM office. Beneficial insects have been in development at Cornell University for some time now to provide land managers and invasive professionals with additional treatment options and many PRISMs are looking for release sites that are suitable for these natural predators of HWA. The key to the success of these varied treatments and the survival of the Eastern Hemlock is better data and knowledge of the increasing range of this dangerous invasive insect. This will allow for more successful and varied treatment statewide. In short, if you see something, say something. We can’t let our hemlock trees go the way of the American Chestnut. This is a fight that New York can win.
This story was originally published in The Overstory, the newsletter of the Southern Adirondack Chapter of the New York Forestry Owners Association. Volume 28, Issue 3.