Eastern Hemlock Health Update

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- Hi, Sanford Smith here from Penn State Extension.

Today we're going to be talking about hemlock wooly adelgid.

It's a big problem in Pennsylvania, and yet many people need to know more about it or they don't know much about it at all and should find out about it, especially if they own forest land.

I'm joined by my colleague Calvin Norman, and he's been working on this subject matter a little bit so I'm gonna ask him a few questions that I hope you'll find helpful.

First is, Calvin, what's so important about wooly adelgid?

- Well, so hemlock wooly adelgid is a non-native insect found here in Pennsylvania.

It's originally from the Pacific Rim, everywhere from California to Tokyo, but now we have it here on the East Coast of the United States.

It attacks all species of hemlock and will kill all the hemlocks that it attacks here on the East Coast.

Hemlocks usually die within five to seven years, and that's a big problem.

To identify hemlock wooly adelgid, what you should do is look for trees that are thinning out.

The insects are a stressor and so these slowly kill the branches on the hemlock and they look like white fuzz on hemlock branches, hence the wooly part of their name.

- Now I wanna make something clear right now.

This is not wooly adelgid back here.

This is actually snow on this hemlock, and this branch is fairly healthy over here, but these branches are dead right here.

Okay, and eventually this takes over the whole tree, doesn't it?

- Yes.

This tree is clearly attacked and it will die from hemlock wooly adelgid if we don't do something.

- Okay, so Calvin, people have been working on this problem for a while.

What are some of the solutions they've come up with or attempts to solve the problem?

- Well, so dealing with hemlock wooly adelgid is very difficult because we have so many hemlocks and they're so important to our ecosystem that it's tough to, you know, treat every single tree out there.

But there are a couple of things that have been tried.

There have been releases of biocontrols of beetles called a Laricobius beetle has been released for the last 20 years.

Unfortunately, it hasn't been super successful at controlling hemlock wooly adelgid.

There are trials of a couple of other insects that are nature to the Pacific Rim that could help control hemlock wooly adelgid, but those insects haven't been released outside of a test scale yet.

- Okay.

- So what we have to do right now are use chemicals.

So the best chemicals that we can use to control hemlock wooly adelgid are two insecticides, imidacloprid and dinotefuran.

Imidacloprid is a long-lasting systemic pesticide, so it's found throughout the tree, and it protects the tree from adelgid attacks for five to seven years.

So it can be a little slow for trees to take up imidaclorprid, but it protects 'em for a long time.

The other pesticide that I mentioned is dinotefuran.

It's a lot faster acting and it protects trees from hemlock elongate scale, which is another topic, but it only protects trees for a year.

- Okay.

Now you mentioned those pesticide names.

Are those the commercial name, or is that the active ingredient?

- That's the active ingredient.

So when you're looking for a pesticide, it might be sold as something different.

But the active ingredient you're looking for imidacloprid or dinotefuran.

Dinotefuran is more expensive than imidaclorprid, and it can be harder to find.

They could both be bought by forest owners and you do not need a license to apply them.

- But let me just make this clear.

This isn't something that you could use over a large area, is it?

- It would be very expensive and it'd be difficult to do over a large area.

Also, imidacloprid has a per acre maximum that you can apply.

So it's unlikely that you're gonna be able to treat an entire forest and protect it for a long time.

The best thing the forest owners can do is to protect trees that are important and meaningful to them or important and meaningful to the habitat.

And then kind of think about what the future of their forest is gonna look like without hemlock.

- And thank you very much for telling us more about that today, and if you've learned something, that's great and please share that this video is available for others that need to learn about hemlock wooly adelgid.

Thank you very much.