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Second episode: CFIA's "Talking Plant Health" podcast series

"The environmental cost of invasive species - they impact so many aspects of our environment. They can lead to reduced soil productivity. They can reduce biodiversity in our ecosystems. When trees are attacked by invasive species, they become stressed, and it makes them susceptible to our native pests and diseases as well."

Ron Neville, Plant Health Survey Biologist, CFIA

Calling all nature lovers: stumped on how and why you should check your trees for Tree Check Month? In this podcast, CFIA expert Ron Neville offers tips and tricks that could save the lives of these beloved giants.

Tree checking tips – Audio transcript

You're tuned in to Chronicle 360, the podcast that brings you closer to CFIA experts, exploring what we do and how we do it.

Host (Heather Louden): Well, the year 2020 has been exceptionally challenging in some very serious and unexpected ways. It is also providing an opportunity to slow down, refocus, and make sure to take care of ourselves and our loved ones. In honour of the International Year of Plant Health, I am joined by Ron Neville today to discuss some of the details of tree checking and how Canadians across the country can utilize these sunny days to help protect the plant life in their community.

Ron, can you tell us a little bit about what you do for CFIA?

Ron Neville: Hi, Heather. Thanks very much. I work as a plant health survey biologist, and I work out of Atlantic Canada. My job is to help our inspection staff when they're out looking for different pests and diseases, and I help with some training and also do some outreach with different partners, other government departments, and members of the public.

Host: Can you give us a broad strokes overview of what tree checking is and why August is a good time to check your trees?

Ron Neville: The tree checking is exactly how it sounds. It involves people going out and looking at the trees, looking at the trees in your yard, and looking at the trees in your neighbourhood. August is actually a really good time of the year to do this. You could do it all throughout the year, but in August, when trees are stressed, they'll actually start showing signs of the stress in the middle of the summer. That's the time of the year when things are hot, there's sometimes there's some droughty conditions, and it's also, of course, directly before a lot of trees will lose their leaves later in September. August is a good time because what happens if a tree is stressed, or because it's attacked by an insect or a disease, then it'll start changing leaf colour early, and that's 1 of the reasons why it's a really good time of the year to look at your trees.

Host: Other than kind of these stress indicators, can you speak a little bit to how invasive species and pests play a role in tree checking?

Ron Neville: See, the purpose or the goal of tree checking is to try and find - to try and determine if a pest or disease has arrived in an area, and so what I'm talking about here is invasive species, so species that are not native to a particular area. Often when they arrive, their damage is subtle at first, and it's usually localized in a small area. It takes a bit of time for the insects and the disease to get established and start spreading, and so when we're doing tree checking, we're able to try and look at as many trees as we can and trying to find those little new introductions, those little sites where those pests or diseases may have arrived.

Host: Tree checking is obviously a very important piece of identifying these issues. Can you speak to the cost, both ecological and economical, that comes with invasive species and disease?

Ron Neville: The costs are high. The environmental cost of invasive species - they impact so many aspects of our environment. They can lead to reduced soil productivity. They can reduce biodiversity in our ecosystems. When trees are attacked by invasive species, they become stressed, and it makes them susceptible to our native pests and diseases as well. There are some trees that have co-evolved relationships with other species, and there's just a suite of different organisms that will sometimes - little insects or something larger, the fish and different things, they rely on ecosystems that have certain species present. When we get an invasive species into an area like that, it just threatens the existence of a number of different plants and animals.

Invasive species have a huge cost to the economy of Canada. For example, it's estimated that every year about $7.5 billion is lost to the agriculture and forest industries because of invasive species, because of an invasive plants, because of invasive insects and diseases that either kill or cause declines in forests, or they result in agriculture systems having to try and manage pests.

Host: Ron, could you go into a little bit more detail about what tree checking looks like?

Ron Neville: Sure, so, you know, it can be as simple as it sounds. It just means just getting outside, trying to be observant. The way I kind of look at the trees in my yard and my neighbourhood is when I'm out walking I first kind of take note of kind of the interesting trees around. I kind of like looking at those, if something's a bit different. When I look at a tree, I kind of look at a tree from a bit further back first. When I'm walking along, or in my yard, I'll actually take a few metres back from the tree and kind of look at the whole crown, and just kind of get a feel for how healthy it looks. Are there areas in the crown where there's foliage missing? Are there leaves that are kind of turning colours before they should be, before I would expect them to? Then, I can kind of look a bit more closely at those areas.

Then, when I get up a little closer, then I can actually start looking at the leaves. I can look for pests. When I look at leaves, I look for things that might be eating the leaves, or eating inside the leaves, or I also look for signs of disease, different orange or browning of different portions of the leaves.

Then, when I'm kind of done sort of assessing that, I'll actually go in and start looking at the trunk and sort of make my way up the tree, looking at the different branches. Many insects when they attack trees will actually start in the crown of the tree and kind of work their way down. Sometimes we have to look really high up in the tree, and what I look for is I look for - I look for holes, so holes that the insects may have exited the tree. It could be a round hole. Sometimes they're little. Sometimes they could be large, maybe close to the size of a dime for the Asian longhorn beetle, for example.

Then, I look for cracks in the bark, because we have cracks in the bark because when the larva is underneath the bark feeding, it destroys that tissue, and when that tissue is destroyed, the tree can no longer grow in that area, then you start getting the bark starting to die, and the bark starts cracking. So I look for that. We look for what's called frass. Frass just kind of looks like sawdust, little pieces of sawdust, and that's what the larva will exude while they feed. They're eating the plant tissue underneath the bark, and frass is what they're leaving behind. This kind of material can actually sometimes be seen peeking through the cracks in the bark, or sometimes accumulating at the bottom of a tree.

Host: Now that we know a little bit more about these pests, Ron, how do they get here? How do they get to Canada?

Ron Neville: We ship all these goods all around the world, and in many cases we're shipping them on pallets. When we have a pest like the Asian longhorn beetle, which is native to China and other Asian countries, the way that it gets brought into Canada can be on wood packing materials. We have rules and regulations and inspections to try and prevent that, but we can't look at every shipment, and from time to time these pests can get through our borders and arrive.

We've had situations at a number of different cities around the world where that pest, the Asian longhorn beetle, was actually imported - we've just recently been dealing with an eradication program in the Toronto area because of that pest. So it can certainly happen.

Another way that these pests get spread around is once they get established - another way that they get spread is by people moving things like firewood. People will sometimes move firewood really, really long distances, and we really, really encourage people to not do that, and just think about the fact that when you look at a piece of firewood, the insects that you could be moving, you can't see that they're there. They're in larval form, and they're underneath the bark, so we really encourage people to buy their firewood where they burn it. If you're able to get out and do some camping this summer or you're heading up to the camp, then just consider that please when you - before you leave is to consider what the impact of maybe you moving that firewood to another area and potentially spreading a pest to a new area.

Host: That's really interesting. I think we have a pretty good idea of how to tree check, and I know that there's a video of you doing a tree check now on our social media channel. If we find an issue with a tree when we're out checking and looking around at our own plant life, what are the next steps that we can take?

Ron Neville: If people are out and you encounter something that you want to report, we'd really like to encourage you to do that. You can go on our website,, and you go to that site and there's a contact us button for reporting of plant pests, and I'd really encourage you to communicate that to us. We'd really appreciate it.

Host: Well, thank you so much, Ron, for taking the time to chat with us about it. I'm sure all of us have learned a little bit something new today.

Ron Neville: Thanks very much.

This has been a Chronicle 360 podcast. For more like this, visit

[End of recording]

Second episode: CFIA's Talking Plant Health podcast series

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