Elongate Hemlock Scale

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Elongate Hemlock Scale

Post by JHarkness » Tue May 15, 2018 4:37 pm

While most, if not all, members of ENTS are aware of the hemlock woolly adelgid, there's another insect killing our beloved hemlocks, it's the elongate hemlock scale, a type of armored scale that sucks fluid from the tree's needles causing the tree's foliage to dry out, die and fall, effectively it's the same damage that HWA causes, however it seems to happen over a much longer period of time. In my area of eastern New York, the HWA is almost nonexistent, but the EHS is causing severe damage to our trees, despite this the NY State Department of Environmental Conservation refuses to do anything this problem, not even researching is on the table at the moment. I'm sure the hemlocks of northwestern CT and southwestern MA are experiencing the same problems, but I do not know the full extent of it yet.

I have seen EHS on my trees for years and always assumed it was HWA but the trees just never seemed to die off, I eventually realized that their health steadily declined very slowly. Last year I realized that what was affecting the trees was not HWA, I quickly identified it as EHS and reported it to NY State, my case simply got pushed off and they claimed that "EHS has never been documented to cause significant harm to the eastern hemlock", after that I never heard back again, but that's simply not what I was seeing. I've sense found quite a few fallen 'skeletons' of hemlocks on my land, and they're all very small trees that shouldn't have died so young, and I've witnessed several trees decline through the years, without a trace of HWA, and finally died this past year. My own trees, as well as trees at several other locations throughout eastern New York have severe scale infestations and only my own trees seem to have any HWA and only four out of my 200-someodd hemlocks have it yet they're all in bad health. Beyond my area, I don't know how bad the damage is, it's possible it's only local, but it wouldn't surprise me if it's a lot more widespread than it's reported to be by state governments.

I haven't seen much information on the pest from other states either, so perhaps there have just been far too few voices speaking up about the damage it's causing, at least on a local scale. Or perhaps most are seeing the scale and identifying it as HWA without even taking a close look.

Here are some reference shots of EHS I took from several locations across eastern NY,, mainly Dutchess and Columbia Counties this past winter:
Stand of hemlocks in Wassaic, all trees in severe decline, out of 220-250 trees I checked none had HWA and only around half a dozen didn't have EHS.
Stand of hemlocks in Wassaic, all trees in severe decline, out of 220-250 trees I checked none had HWA and only around half a dozen didn't have EHS.

If anyone with ENTS has observed EHS and a lack of HWA on trees in poor health, please do report this to the appropriate organizations for your region. I think if enough people speak up about this problem, maybe someone will recognize it and something can be done about it eventually.
"Be not simply good; be good for something." Henry David Thoreau

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Larry Tucei
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Re: Elongate Hemlock Scale

Post by Larry Tucei » Wed May 16, 2018 8:44 am

Oh Wow another issue for the great Hemlocks to deal with. Although I don't have any Hemlocks in my region I'm glad you shared this with NTS. There are many of our members that have been dealing with the Hemlocks. Larry

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Re: Elongate Hemlock Scale

Post by dbhguru » Wed May 16, 2018 4:02 pm


We're aware of it in Massachusetts. The state DCR is attempting to combat it, but with virtually no funding.

Robert T. Leverett
Co-founder, Native Native Tree Society
Co-founder and President
Friends of Mohawk Trail State Forest
Co-founder, National Cadre

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