Orchard People

[00:00:00] Introduction and Show Overview
The following program does not necessarily represent the views and opinions of Reality Radio 101, its advertisers and sponsors, or its listening audience. Listener discretion is advised.
Welcome to the Urban Forestry Radio Show here on Reality Radio 101. In this radio show and podcast, we learn about fruit trees, permaculture, aboriculture, and so much more. So if you love trees, and especially fruit trees, or if you're interested in living a more sustainable life, then this is the place for you.
I'm your host, Susan Poizner, of the fruit tree care training website, OrchardPeople. com. Thanks for tuning in! And enjoy the show.
Welcome to the Urban Forestry Radio Show with your host Susan Poizner. To contact Susan live right now send her an email instudio101@gmail.com.
And now right to your host of the Urban Forestry Radio Show Susan Poizner.
[00:01:37] Midwinter Reflections and Show Format
Hi, everyone. Here in Toronto, it's midwinter, a bit of a dreary time of year. The spring seems so far away, and the winter just keeps going. As a survival strategy, some of us focus on reading seed catalogs and dreaming about what we will plant this spring.
Now, as an urban orchardist, it's also a nice time for me to think about everything I've learned this past year, about growing fruit trees, orchards, and perennial edibles. And this month I've decided to do a pre recorded program featuring some of the best interviews I've had on the show in the past year.
And it's going to be a real mixed bag.
[00:02:21] Seabuckthorn Adventure in Siberia
We'll start off in Siberia. with the story of researcher Bill Schroeder, who went to that freezing cold part of Russia and learned about seabuckthorn. He was fascinated. The Russians were using seabuckthorn berries to develop highly nutritious food for cosmonauts in their space program.
And he thought it'd be a great idea to bring these plants to Canada and to breed them for our own unique conditions and needs. Now, if that story is one of adventure, my next story could be made into a horror film. That was when I spoke to author Jessica Walliser about the gruesome bug eat bug world out there.
Jessica is the author of Attracting Beneficial Bugs to Your Garden, and she introduced me into the world of parasites, predators, and pollinators. It's a great interview, but you may not want to be eating your lunch at that time. Now in the second half of the show, we'll talk about fire blight, a nasty disease that strikes fear into anyone who grows apple pear or Asian pear trees.
We'll explore what this disease is.
Finally, we'll end this show by looking into a crystal ball to see the future of growing fruit trees and how the realities of climate change may affect the trees that we will need to grow.
So we'll start our show today with a story of seabuckthorn plants cultivated extensively by the Russians in the 1980s. These plants produce bright orange berries that are nutrient rich. And that have lots of health benefits. The Russians grew the plants in order to produce seabuckthorn extract. And they used that as a supplement for their cosmonauts.
The seabuckthorn extract was also supposed to help protect those cosmonauts from radiation. In 1985, Canadian researcher Bill Schroeder visited Siberia on a seed collection mission, and he noticed acres and acres of these amazing orange berry shrubs. He learned more about them and thought, Hey, someone should bring this plant to Canada and breed it for Canadian production.
And so that is exactly what he did. I spoke to Bill Schroeder of Agriculture and Agri Food Canada's Swift Current Research and Development Centre in Indian Head, Saskatchewan. And he told me his story. it, there's a bit of a history to it. I'm a plant collector. and have been, on many expeditions, mainly to very northern climates of Siberia and northern China.
And in 1985, I was, on a seed collection mission looking for different types of, tree and shrub species for use in shelter belts. And as we were traveling throughout the Siberian countryside, I noticed these huge Areas and acreages, acres of orange buried shrubs. So I, finally had to get them to stop the Jeep and we got out and we had a look at these, plants and I had instantly recommended, recognized them as C.
buckthorn, which was a plant we've been growing in the Canadian prairies, probably since the 1950s for shelter belts. And other revegetation type projects. we had never thought them as a fruit, fruit, producing shrub. We thought them more as a shrub that could be used to stabilize soil. But what I found when I was in Siberia was that the, the Russian government was planting extensive acreages of this, plant to supply, fruit concentrate for use in their space program. So what was happening is the cosmonauts were taking seabuckthorn extract into space with them, both as an ointment to, to, to put on their skin and to, Prevent radiation or UV radiation burn, but also as a food supplement because of its high nutritious, content.
So that got me very interested. this is a shrub that we can, we grow very well in Canada. And, it's got these very unique characteristics that we really hadn't thought of before. And I thought of, I can relate the Sort of the, rise of seabuckthorn after that visit, a talented performer or artist that, that sort of worked in obscurity for many years, but, finally is going to become an overnight success.
And so I thought, that might just happen with seabuckthorn, and once, if it's brought to the North American market.
[00:07:51] Challenges and Successes in Seabuckthorn Breeding
so you brought back seeds or cuttings, from Siberia? The first, my first trip, I just brought back memories and when I'd seen my next trip, which was two years later to the same area, I had made arrangements to actually specifically meet with some of the seabuckthorn breeders in Russia and made arrangements with them to provide me with some germplasm in the form of seed that I would bring back to Canada.
And that was the start of what. began as a, 25 year long breeding program. Now you worked on this. Amazing. For 25 years, you were developing different varieties of Seabuckthorn. But Bill, what was wrong with just planting the seeds here and using the Russian, varieties? I think there's a couple of things there.
One is that Seabuckthorn is dioecious. So the male and female plants are separate, of course. And. If you're planting just seeds as we were doing in Shelterbelts for all those years, you get about a 50 50 ratio of male and female plants. So planting seedlings for fruit production isn't the most efficient use of the area.
The other thing with the Russian cultivars that have been developed, and they were very well adapted to that area of Siberia. And some of the varieties that I did bring back with me to test in the prairies did fairly well. But I We really thought that we needed to have a Canadian developed and fully adapted seabuckthorn varieties that Saskatchewan and Alberta and Manitoba, and for that matter, Canadian growers could say this plant was developed for our use, it's specific for our needs, and they could use that as an opportunity to mark a Canadian.
bred and developed Seabuckthorn plant. So when you were developing these plants, what qualities were you looking for? Bigger berries or longer, I don't know. What were the qualities you were hoping to imbue into these plants? breeding for a larger berry is not that difficult. it's just a matter of selecting individuals with large berries and And so it's a fairly easy task.
so we very quickly got some very large fruited plants. Now, as the name Seabuckthorn tells you, it can be a very thorny plant. So this was the, area that I really focused my breeding program on, was to trying to develop a large fruited, thornless variety. And to do that, I needed to Conducted many different crosses using many different parental lines to try to bring forward some of the genes that were, that would develop a thornless, plant.
And what I found is that the gene for thornlessness really came from the male plant. So when I was identified thornless male plants, I could very regularly transfer that thornless gene into the, the, female plant. Using the, the gene that's coming from the male. So how many different varieties did you develop over the 25 years?
I think, when I think of varieties that I released, I, ended up releasing four varieties. But to get to that four varieties, we screened over 25, 000 individual genotypes. and from there we went to about 120 promising. individual cultivars and from that, those 120 promising cultivars, we ended up with four cultivars that were officially released, and are available to growers.
Okay, and what are those cultivars? they're, the first one that we released was called Harvest Moon. the second was Orange September, and the, the third was Autumn Glow. And the last one is Prairie Sunset. And, for instance, if I were, was thinking of planting, Seabuckthorn, how would I choose?
What's the difference in general between these varieties? they all have very large fruit. They all have, are quite sweet. So if you, when we measure sweetness in bricks, so the bricks value would be greater than 10. And for all four varieties, what really separates them, I think, is mainly their mature, or when they mature, when their fruit is ripe.
Harvest moon is mature, matures fairly early. Orange September is fairly late. And Prairie Sunset and Autumn Glow are somewhat in between. And when I say mature, the difference of maturity might be up to three to four weeks. Oh! So if Harvest Moon is maturing, In mid August, which it does in Saskatchewan.
Orange September would be maturing in probably the first week of September. So there's quite a range of time between when the how long it takes for the fruit to reach the point where you want to harvest it. So that's great for somebody who's thinking of starting a small orchard, and that means that they can be supplying these berries to manufacturers or to the public for quite a few months.
Yes, and that's, I'm a big supporter of diversity in an orchard and having cultivars that are Certainly not identical, but will give you these opportunities to extend your, harvest season and, and also I find that, by doing that, you, have a better handle on any, management of any diseases and insect pests that, that may occur, although I must say that, C.
buckthorn has very, we've found very few insect and disease problems, in Canada. compared to what I've seen in Europe and in, in, in Russia. Okay, so you, over the years, you released these varieties. Did it take off right away? Was it the overnight success that you dreamed of? Not really. Yeah, one could have hoped that, that we could get the, the plant material into, into the hands of growers very quickly, but that didn't happen.
It's, it's a small niche market, I found that most, a lot of the nurseries weren't familiar with the plant, there wasn't much ornamental value to it, so there wasn't a lot of interest in propagating on large scale. The other thing that, that growers, when they're, planting fruit varieties, they don't want to spend the same amount of money as you would for ornamental plants.
it was, really difficult to convince. Propagators that they should be growing seabuckthorn. It's sort of the chicken and egg thing, The, growers wanted it, but they, at the time the markets were a little bit soft. They didn't know where they were going to sell them.
so, the nursery men, they didn't really have a, feel there was a strong enough market to really put a lot of effort into. Now, The nice thing about seabuckthorn is it's very easy to propagate. it grows very well from hardwood cuttings as well as softwood cuttings, so it's not a difficult plant to propagate.
once nurseries became aware of that, they seemed to, to, take the lead. And at this time, I think that there are nurseries that are actually producing some of these cultivars. At the same time, however, there is a lot of C. bacterial material that's coming in from, Europe and, and Russia.
not that's a bad thing, although I, am somewhat concerned of the transm transmission of some disease, an insect, particular disease, an insect pest that may, affect the long term viability of the industry in Canada. as I said before, we're, we've been fortunate that we've been able to stay relatively disease and insect free with, C.
buckthorn. but it's always a concern when you're bringing material in from overseas that you may, inadvertently introduce some, new pests. That was Bill Schroeder of Agriculture and Agri Food Canada's SWIFT Current Research and Development Centre. In Indian head, Saskatchewan to hear more of the interview where Bill talks about how to grow seabuckthorn and he answers some listener questions, visit orchardpeople.
com slash podcast and listen to episode 10 of the urban forestry radio show.
[00:17:42] Beneficial Bugs and Garden Ecosystems
So let's return from Russia and from our seabuckthorn adventure. It's time to grab a magnifying glass and have a look at what's going on in our own backyards. And I'll warn you, it's not always a pretty sight. There are so many insects out there and those little creatures have rich and sometimes scary lives.
And they all have a role to play in our gardens. So in Episode 3 of the Urban Forestry Radio Show, I spoke to Jessica Walliser. She's the author of Attracting Beneficial Bugs to Your Garden. I started off by asking Jessica what her goal was. My goal was essentially really to, connect the, happenings of the entomological community to those of the gardening community.
some of the research that's taking place, with entomologists around North America is really pertinent to home gardeners and also to commercial farmers and market growers. But yet, That research wasn't making its way to the home gardeners and or if it was only a very, limited And so what I wanted to do in this book was really create a easy to use, easy to understand bridge between all of these amazing studies that talk about how good beneficial insects are for the landscape, bring all of that to the home gardener.
teach them how to use those studies to benefit themselves and how to really build a, an ecosystem in the garden that fosters beneficial insects and then in turn helps us control the pests. it's funny because you talk about beneficial insects and before I read your book, I thought of pollinators.
Okay, beneficial insects are our happy little pollinators that come and help us pollinate our fruit trees and zucchini plants, whatever. but what else do beneficial insects do? we can basically talk about three different groups of beneficial insects. The first would be those pollinators, which would be things like our native bees, some beetle species, flies, butterflies, even hummingbirds fit into that category, but then the other two.
Groups, which would be the predators and the parasitoids. What their job is to do is, they're good bugs because they help us control some of the pests that commonly feed in our garden. they are, just as important as pollinators in my mind because they help us get a very important balance, which in turn helps us to reduce pesticide usage, in our gardens.
And you said there were three groups. What's the third group? The parasitoids. Oh, I see. yeah. So predators are, excuse me, predators are insects that capture and consume another insect directly. So if you think about a spider, or a praying mantis, or even a ladybug, they capture that aphid, or that, stink bug, or another insect, and they Eat it directly.
The parasitoids, how they work is they use that pest insect to house and feed their developing young. So this might be a parasitic wasp or a cactus fly, where the female will come along and she'll insert an egg into the back of a tent caterpillar. And that egg will hatch and the larva will tunnel into the tent caterpillar and consume it from the inside out, eventually leading to death.
So a parasitoid is a lot like a parasite. Except a parasite leaves its host alive, and a parasitoid brings eventual death to the host. those are, those are the two main groups of beneficial insects that are not the pollinators. It's so funny because I know, Jessica, you started like I did.
You're a gardener. You weren't necessarily an expert in this. Were you like me when you started to realize how brutal this part of our garden's is, it's like a zombie, a mini zombie apocalypse there, all these bugs eating other bugs from the inside. Yeah, but it's just a when you come to think about and you can compare it to something that is a little more on our scale, which would be, the lions and the gazelle or the bobcats and the rabbits, or even a bass and a minnow, right?
sort of the predator and it's called the predator and prey cycle. And it exists in every ecosystem on this planet. So it would only make sense that it also exists in the insect world as well. But of course that's on a much smaller scale than we are. And We tend to not even notice that it's happening, but right outside our back doors every day, all day long.
It's a bug eat bug world. and you might think of it as gory and, your introduction, I was, had a big smile on my face as, you were giving your introduction because it's true. That's exactly what it is. it's not, necessarily a nice thing to witness, but, it's just part of the ecosystem of the garden.
Amazing. Now, it's interesting because for most of us gardeners, especially those of us who are planting perennial crops and fruit trees, our concern is the bad bugs. So we are annoyed to see that insects are eating the leaves of our trees, or are laying their eggs under the skin of the fruit growing in the trees and stuff like that.
Why, we don't necessarily think of beneficial insects. What is, what's the relationship between good bugs and bad bugs? it's interesting that because so far on this planet, we have managed to identify about 1 million species of insects. But scientists estimate that there's between 2 and 20 million different Insect species on the planet.
So we barely managed to identify the tip of the iceberg. But what we do know about that 1 million or so species that we have managed to identify is that actually less than 1 percent of them are considered to be So we've got an incredibly small percentage of the insects that are out in your backyard that actually bring harm to your garden.
But those tend to be the ones that we focus on. We spend money, we spend time, we spend energy, and we really focus on controlling those bad insects. If we could just flip our mindset around and begin to put that much time and energy and not even money. You could put money, and invest that instead into nurturing and encouraging the beneficial insect.
What we would see once we start to focus on them is we do start to see a natural reduction in pest numbers because we've gotten that balance back into the garden that we lose every time we go out and we try to fight the bad guy. so it's a matter of switching your mindset. It's not an easy one, but that's another purpose of this book, is to really educate people what studies are out there, what they have shown, and how you can effectively use these techniques in your own landscape.
So if I were to buy into this whole concept and, read the studies and, say, okay, I'm convinced, would I no longer use sprays, whether they're organic sprays like, lime sulfur and dormant oil or non organic sprays that many conventional, farmers and orchardists use. Would we just walk away from that part of, pest control in our gardens and orchards?
Yeah, I get that question a lot, and here's the thing. there are natural predator and prey cycle, which we talked about, and all these going on in the insect world, but the biggest trouble that we've gotten ourselves into is the fact that many of the pests that we have to deal with in our yards and gardens and orchards are not native.
To the place in which we live. for example, the oriental fruit moth, which is really wreaking havoc for a lot of farmers and growers now, that's an introduced species. And when we brought it over here, accidentally, what happened was we didn't bring The, predators and parasitoids that have evolved to help keep a natural control, we didn't bring those along, too.
So this insect came here with no natural controls in place, no system that checks and balances. Of course, the population explodes because nobody's there to keep it in check. And those are the instances where we really find ourselves having to turn to products to help control it. Same too with the brown marmorated stink bug.
I know here in the east, our orchardists in Pennsylvania are having a huge amount of trouble with this introduced, species. The other, thing is, when you're growing anything in a monoculture, when you have rows and rows of the same fruit tree, that is essentially a big giant target.
And so we have to work a little harder to get that balance in place, when we have a big monoculture like that. So no. Doing this system is not going to, completely eliminate the need for, your organic pest controls that you use, but however, it is intended to greatly reduce that and to make you think a little bit harder about the choices that you make.
It's funny because you talk about monocultures and I always say that like a monoculture of let's say all apple trees is like an all you can eat buffet for bad bugs, they can have as much as they want. Yeah, it really is. And there's a great concept. one of the things that I got to do in this book, which was really literally my favorite part of writing this book, was that I got to interview entomologists.
from all across North America and talk to them about some of the projects that they're working on. And, there's an entomologist with the National Sustainable Agricultural Informational Service named Rex Starfour, and I had a, have a great interview with him in the book about the concept of farmscaping, which is basically taking that in big orchard full of apples that for commercial production, that's what you have to have.
And instead of just having it. A big, lines of apples in a row. We start introducing other elements to it. whether it's something like a hedgerow or ground covers or windbreaks or flowering, rows of flowering, plants and annuals in between. And we create more of a landscape out instead of a monoculture.
And when we increase that complexity of the orchard. What we find in the natural reduction in pests and a natural increase in predation. and there's a really interesting study that, the rates of parrot parasitism in orchards for things like tent caterpillars and codling moth caterpillars, in orchards that have flowering plants and weeds allowed to have a substantial portion in that orchard.
There's an 18 times. 18th rate increase in the parasitism. So when we get different elements of complexity in the orchard and step away from that monoculture, we have a greater chance of naturally reducing those pest numbers. So here you wrote this beautiful book, and it's for gardeners. And is what you're saying that the plants that we choose can help to bring this balance into place, that just by planting the right things we can attract these, beneficial insects.
Is that your philosophy? Absolutely. Yeah, we can attract them and even more importantly, we can support them. So we can create this habitat for them where they're getting what they need as far as food, resources. They're also getting habitat, egg laying sites. places to hunker down for the winter when they have all that they need, then their populations naturally increase and we get better and better predation, and, and predatory results.
And so it's really a cool system and there's tons of research to back it up, which I wanted to have in this book because I think that's so important. You just can't say it works. You actually have to have the proof to back it up. That was Jessica Walliser, author of Attracting Beneficial Bugs to Your Garden.
And it's well worth your time to listen back to Episode 3 of the Urban Forestry Radio Show, because Jessica continues on to tell me six ways to attract beneficial insects to your garden. And one of them is planting a beetle bank. That, to me, sounds like a worthwhile investment. I'm Susan Poizner from the Fruit Tree Care Education website, OrchardPeople.
com. You're listening to a special pre recorded episode of the Urban Forestry Radio Show on RealityRadio101. com. And thanks for listening. We're coming up after the break.
[00:30:41] Fire Blight: The Dreaded Fruit Tree Disease
We will discover why fire blight Is not a farmer's friend. Coming up.
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You're listening to the Urban Forestry Radio Show on Reality Radio 101. I'm Susan Poizner from the Fruit Tree Care Training website, OrchardPeople. com. In this special program, I'm bringing you some of the best interviews in the program in the last year. Now, in the first half of the show, we spoke about a researcher's seabuckthorn adventure in Russia and about how beneficial bugs Can be very scary and why you may not want to meet them in a dark alley if you are a fellow bug.
Now in the next interview, I talked to an expert about one of the most dreaded fruit tree diseases if you grow apples or if you grow pear trees. It's fire blight, and to an outsider, the symptoms of fire blight may look innocent enough. The brown, burnt out looking branches may just look like branched dieback.
[00:34:26] Introduction to Fire Blight
The result, perhaps, of not watering your tree enough. But, it's much more wicked than that. Fire blight can take out entire orchards.
[00:34:37] Interview with Dr. Kari A. Peter
I spoke about it with Dr. Kari, a Peter, assistant professor of Fruit Tree Pathology at Penn State Fruit Research and Extension Center. I started by asking her to explain a little bit about what she does.
my role is the Tree Fruit Pathologist for the state of Pennsylvania. So I take care of. Managing tree fruit diseases, educating growers and how to manage diseases of their tree fruit tree. So tree fruit includes apples, pears, peaches, nectarines, apricots, plums. And one of those diseases that I help growers try to manage and not get the better of them is fire blight.
So to what extent have you been seeing fire blight in your area in recent years? I started in 2013, and that was a relatively calm year, and then in 2014, I called it the year that Mother Nature hazed me, and that was an awful fire blight year, and I actually, that was actually considered an epidemic, year, and it, the entire Northeast was affected by fire blight last year, in 2014, and it was also affected in 2015 as well.
And The reason was due to the environmental conditions. It was warm and wet during the right time, and then this year, the season for fire blight wasn't as bad, but we dodged a bullet. However, there are our neighbors around us, and the north and east of us weren't as lucky. So it's been a challenging few years.
[00:36:15] Understanding Fire Blight
what exactly is fire blight and how does it spread? The fire blight, it's a bacterial disease, and it's native to North America. so that's what makes it especially challenging. It's endemic in North America. And, the fire blight, it's, The most vulnerable stage of the tree is during bloom time.
And the bacteria finds its way to the bloom by either, insects or splashing rain or water. It can infect the bloom, due to openings in the base of the bloom. And when the bacteria enter that, those, openings at the base of the bloom called nectaries, it gets in the bloom and in the tree and it can cause disease right there and then in the blossom.
So we call that blossom blight. When the disease progresses in the tree at that stage, you can get oozing, bacterial ooze. And it can continue to spread throughout the tree, and that's when we can see the characteristic shoot blight, where the young, tender shoots of growing trees are especially susceptible.
We'll see that shepherd's crook, that characteristic shepherd's crook or candy cane. Now, when we see that, the disease progression in the tree, it will kill the plant tissue, and it will create a canker. That canker will serve as the overwintering source from year to year as a place for, the fire blight bacteria to perpetuate.
And so the bacteria will, live at that region of dead and living tissue. And so that is where the source of bacteria that is available to cause disease comes from every year. So that's really interesting. So they, so it sounds like it comes in with, at bloom time, it sneaks in via the blooms, and it sounds like it works its way through the branches into, I don't know, does it get to the trunk of the tree if you wait long enough, or?
Depending on how old the tree is, the younger the tree, the more susceptible it is to get infection in the trunk. And so if it's a brand new tree, you could have possibly tree death in the same year. Exactly. Yeah, I've seen that. Unfortunately, here in Toronto, we've had severe problems this year. Apparently, it started last year.
I didn't see it this year. Boom. It's been all over. It's been very challenging. so Okay, you talk about cankers now for those listeners who may or may not know the cankers the canker can be all sorts of things You can look like an oozing sore on the tree or an hard patch Is there something in particular that the canker a fire blight canker will look like a dark?
As far as what it's how it's different oftentimes you'll see at the base of a dead body area of tissue. So that's a real telltale find that if you see a dead shoot And you trace back that the death of the tibetan shoots, the necrosis, the browning area to the back, you can see, it looks like a sunken area of the branch, it looks, the bark looks wrinkled, it's blackened or brown and It's, there's a misconception that this is the plant's response.
It's actually a good thing, and that's incorrect. The canker is actually, it's dead tissue that is caused by the bacteria. it's interesting.
[00:39:39] Listener Questions and Expert Advice: Fire Blight Management Strategies
We've had already a lot of emails coming into the studio, and one of them just jumped up, jumped out at me. So it's from Lisa here in Toronto. And she sent some pictures.
Unfortunately, I don't know. I'll send them to you later to have a look at, but she says here are a few pics of Asian pear and sweet cherry trees at San Romano Orchard, which is where she is. Can you help us identify what is trying to attack these trees and the best way to deal with it? I would like to know if it's acceptable to prune each individual suffering leaf.
And also, does a fruit tree have the ability to heal itself in any way? Now, I know this particular orchard and, in some of the trees you're getting, it's It starts off, at least with the pear trees, I'm not sure about the cherries, you get blackening around the edge of the leaf. So she's just wondering, hey, can I get this early?
What comment do you have for Lisa? So as far as, if it's, if it is fire blight and the season's dry, you could get ahead of it where you could prune back the branch. You don't necessarily want to just prune off the leaves. You need to prune out the wood. And so the, wood is what has to be removed because the, if it truly is bacterial, the bacteria is going to be in, in the plant's vascular system, in the veins.
And that's basically the major conduit system in the plant that allows transport of water and, nutrients. So it's important to get it, you want to prune ahead of where you see the decline of the branch. So in the case of Asian pears, that's what you would want to do. And in the case of cherries, depending on what it is, again, if it is something either bacterial or fungal, you would want to get, you want to prune beyond that stage of where you see the disease progressing.
And during the summer months, the tree can form a callus over where you prune. And that is a way it, quote unquote, heals itself, it heals that area, so it no longer is susceptible to something that could be penetrating into the tree at that open wound, because a pruning cut is a wound. pruning in the summer, often times, is better, in some cases, for some diseases, because there is recovery time for the tree.
but the main management strategy for fire blight, though, is actually to wait until Winter to be able to prune out the diseased areas because we're ensure that the bacteria has stopped moving through the tree. It stops spreading when it stops spreading that minimizes the chance of you. the pruner of spreading the disease because there is a high probability of spreading the disease.
during the summer months, just because of the conditions that could be present, environmental conditions that could be present at the time. That's interesting, because that's what I was going to ask you. when you read about fire blight, it always says it starts with the blossoms, and so you think, hey, it's July, it's August, nothing to worry about.
If there's fire blight in there already, in my tree already, okay, I have a problem, but if the tree, if another tree doesn't have fire blight, I don't have to worry about it getting in, because it's, that's not blossoming. Is that the case? Not necessarily. if the tree, if you, don't have blossoms like that is terrific.
However, if your tree continues to grow through the summer months and oftentimes, depending on how much rain occurs, we could get growth through the whole season. But typically fruit trees stop growing in July. And, but up until that point, if there's succulent shoot growth, Meaning nice green tender shoots.
Those tender shoots are still very susceptible to fire blight and getting the fire blight infection that characteristic shoot blighter, the shepherd's crook and insects are very drawn to succulent shoots. they could feed on those succulent shoots, creating a wound. And if there's any bacteria around that bacteria.
Could then cause disease on that brand new shoot just because of that insect wound. there's still, growers still have to be, or in homeowners still have to be pretty vigilant until about halfway through the summer when the trees stop growing. They start shifting their energies. From pushing out new growth to if the tree produces fruit, they shift their energy to producing fruit like halfway through the season.
And so when the tree, branches and shoots are no longer green and succulent, we call it now hardening off. the bacteria can't penetrate those shoots. So growers still, and homeowners still have to be pretty vigilant until about, mid July or so. So when you say vigilant, it's don't prune it off in the hot season.
Just because, from what I understand from what you're saying is that the pruning itself does create a wound. Perhaps that bacteria Can get in there before the wound heals itself up. So maybe very well depending on how prevalent the disease could be In that area and since I know you know your region is experiencing a pretty bad fire blight year You know if there's more than two or three shoots on a young tree It really behooves the person to not do anything because you could make the situation worse by pruning out the branches, you're creating wounds, there's a chance of spreading the disease because the tree is encouraged to grow now that it's being pruned and that's just going to cause more succulent shoots which become more susceptible to fire blight.
So it's a vicious cycle. It can be a very vicious cycle during a bad fire blight year. That was Dr. Kari A. Peter, Assistant Professor of Fruit Tree Pathology at Penn State Fruit Research and Extension Center. To hear the rest of the interview, listen to episode 12 of the Urban Forestry Radio Show. You can find the podcast at orchardpeople.
com. You're listening to the Urban Forestry Radio Show on Reality Radio 101.
[00:46:02] Future of Fruit Tree Growing
Coming up, we'll dust off our Urban Forestry Radio Show crystal ball and explore how growing fruit trees is going to look different in the future as a result of climate change. I'm Susan Poizner, and we'll be back after this short break.
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This is the Urban Forestry Radio Show on Reality Radio 1 0 1. I'm Susan Poiser, and in this show I cover fruit trees, food forests, and our Bora culture. Thanks for tuning in. So we're going to wrap up the show today with a peek into our urban forestry radio show, Crystal Ball, which we keep here in the studio.
My goal is to see what fruit tree growing will look like in the future.
[00:49:28] Impact of Climate Change on Fruit Trees
we are now facing the challenge of climate change. And instead of being able to rely on weather conditions that we always had, we're facing new uncertainties. So in Episode 8 of the Urban Forestry Radio Show, I spoke with Michael Gregory Peck, Ph.
D., Assistant Professor of Horticulture and Sustainable Fruit Production Systems at Cornell University. And we spoke about how climate change affects fruit trees today and how we can prepare for the future. But first, I asked him how he got into this field. Sure. so I actually, maybe like a lot of your listeners come from a suburban environment, didn't have a background in agriculture, but got very interested in it during college, spent some time actually working on farms in California.
Actually in an apple tree nursery and, from there, my interest in the, science of how, plants work and more specifically how, tree fruit work and how we can produce them more sustainably became a passion of mine and a career of mine and went on to graduate school at Washington State University and then my PhD at Cornell University.
I understand that a lot of what you do involves the challenges of growing fruit trees and understanding how fruit trees work. do you feel that, that climate change is one of the challenges that our fruit trees are now facing? Absolutely. there's no question that. The weirdness, as you described it, of the weather that we experience, these shorter term episodes where we have ice storms or we have these early spring events, a lot of them can be attributed back to larger patterns and, changes that are happening in our Global climate.
so why is this a problem for fruit trees? Their job is just we care for them and their job is to give us fruit. so where is the problem? we are, managers of, the trees, but the trees are, natural, natural, plants and they are, yeah. responding to the environment around them.
And if the environment changes, then the plants also need to change. Or, we need to change how we manage them. And for tree fruit, which are, have a very long life cycle, naturally they change very slowly. It takes generations and generations for plants to change, unless through concerted breeding efforts.
that leaves us with needing to develop management tools. To be able to produce tree fruit in a changing climate. let's talk about some of the problems. And for myself, as a community orchardist here in Toronto, as I said in my introduction, we have had these early springs and then you get a late frost.
And I remember the first time that happened. I was talking to one of my mentors and I said, the blossoms are open in the park and my apricot trees or whatever it were, they were blossoming and everything looks good, but there was this freeze. And I said, is this a problem? What could happen? So what are the problems that can happen to fruit trees as a result of this?
I was told that the blossoms could die as a result of the frost and then you have no fruit at all that year. Is that the case? What are these problems that we can expect to see? there are many, and I think you hit on one of the biggest challenges that we're going to have for tree fruit production.
many of our fruit trees, are, deciduous. that includes apples and pears and peaches, cherries, plums. They go through a period of dormancy in the winter. There's no leaves, there's very little active growth. The trees are And then they start to grow again in the spring. And the first thing that they do is that they bloom.
And so that is a, evolutionary mechanism that they've developed in order to attract pollinators and also to provide them with a long growing season to create fruit. And to allow for seed dispersal. So there's a lot of advantages to being spring blooming, a spring blooming plant. But as you pointed out, there's also a disadvantage, and you hit on the key one, which is frost.
And so frost is a challenge that growers of tree fruits have always had with these crops. But what we're seeing is a shift, and a shift of the phenology, which is the Understanding of the progression of from bud break through flowering, moving earlier and earlier in the spring, earlier and earlier in the year.
And so that increases our chance for having a spring frost. And as you said, those frosts are very damaging to flowers. And so flowers are very sensitive to cold temperatures. So if there was, and please, I'm not asking for this universe, but if there was a frost tomorrow, our buds are starting to break here in Toronto.
I don't know what it's like there. They're just starting to break. If there was a frost, would these buds die? what does that mean? Does that damage the tree? Does that just mean no fruit? What happens? And how do I know if the buds are dead? Great question. during the winter, during dormancy, what we call endodormancy, which is this state of rest in the tree, the trees actually, and the buds specifically, are in a state.
Where they can handle very cold temperatures and that's why you're able to grow apples in Toronto and I'm able to grow apples in New York. And so they can handle these temperatures down to minus 20 Fahrenheit when they're in a state of dormancy. But as that progression from bud break to flowering starts, the cold hardiness of those buds becomes less and less.
So as you go from bud break to flowering. To fruit set, what happens is that they can handle, temperatures that are, not as low as you go through there. as you get to flowering and you're at full bloom, the trees may not be able to handle temperatures much below freezing. Yeah.
Interesting. Yeah. So, basically your flowers will not survive. it wouldn't mean that the tree itself would die. It would just mean no fruit that year, Correct. The wood on the tree and the roots of the tree can handle temperatures that are much colder. Then the flowers can.
[00:56:28] Adapting to Climate Change
So would you say this issue of early bud break, late frost, that's the main problem when it comes to the dangers brought to us by climate change?
Or is there other problems? I would say that is one of the primary issues that we're starting to encounter. And I would not say it is the only, only problem that we're going to have with climate change. we have a potential for a lot of different, effects to impact tree fruit production, whether it's for a commercial apple grower or for you in your community garden.
so we're going to have, with climate change, more heat. And then we have the potential for more heat stress that can lead to physiological disorders, like bitter pit, sunburn on the fruit. It could, are. our weather patterns are going to change and we may have more drought periods, which means in areas that previously had ample rainfall in the summertime, they may now need irrigation in order to keep those trees alive.
We also are going to see changes in, the amount of disease that we have with more rainfall. That's the potential for more disease incident events to happen, and also for insects. our insects go through multiple generations, and many of our pest insects will go through multiple generations in a single season.
for example, the classic worm in the apple, the codling moth. Typically, in our environment here in central New York, we'll have two generations per year. If we have a growing season that's four weeks longer, it's, we have the potential of having a third generation. So that's that much more opportunity for, to have, pest damage to our fruit.
Wow. So that doesn't sound like good news, but maybe this is a silly question. If it's getting warmer, maybe we'll get to plant some trees for warmer zones. Maybe we'll be growing in Toronto or New York, I don't know, mango trees, citrus. We would be in big trouble if we start growing tropical tree fruit in Toronto.
that would be one of the, signal that global climate change has. We've reached an apex of massive change, but, but we could see very likely a change in the varieties that we're growing. So we talked about the spring frost and that the danger of losing our crop due to a frost event. perhaps we start selecting varieties that are going to bloom later in the season.
And so that way they escape the spring frost. We also may have potential for a longer growing season. So some varieties that we have a hard time ripening, like Granny Smith or Pink Lady, we may be able to actually grow in our climate now. So there will be some changes. It might not be as extreme as mangoes and, and outdoor lemon trees here.
So I sure hope it's not that extreme. I hope not too. I, found it interesting what you said in the beginning of the show. So, we see the changes coming for whatever reason, because of this climate change or, changing climate or challenges in the climate, whatever you want to call it. But what's interesting is trees have.
Over the millennia, have been changing and adapting and, they are the way they are because they grew to be that way over time. Will they change and adapt to our new climate situation, our new climate reality? I have no doubt that nature, has the ability to adapt. And certainly the world, the globe has gone through numerous climate changes, colder and warmer.
over the course of history, however, the, what's unprecedented about what's happening right now is how quickly it's changing. And so we're talking about climate change factors that are going to be impacting us within 50 years or a hundred years. And for perennial crops like apples and peaches, which have a very long generation time.
They're not going to adapt that quickly. Not without some sort of human intervention through a breeding program. That was Gregory Michael Peck, Ph. D., Assistant Professor of Horticulture and Sustainable Fruit Production Systems at Cornell University. Our conversation about what fruit growers can do to prepare for climate change continued on.
And you can listen to the rest of the interview by checking out the podcast of Episode 8, of the Urban Forestry Radio Show. You can find it at orchardpeople. com slash podcast.
[01:01:22] Conclusion and Final Thoughts
that's all for this little trip down memory lane and it's been a great year for the Urban Forestry Radio Show. Hopefully there will be lots and lots more interesting episodes and guests in the year to come.
I am so grateful for all of the fantastic guests I've had on the show in the last year. And I'm really grateful for my fantastic listeners who email in their questions and comments during the live shows. I love hearing from you. So do tune in again next month. The Urban Forestry Radio Show runs on the last Tuesday of every month at 1 p.
m. Eastern on realityradio101. com, and if you want an email reminder about upcoming shows, sign up for my monthly newsletter at orchardpeople. com, which covers fruit trees, forest gardens, permaculture, You're listening to the Urban Forestry Radio Show. I'm Susan Poizner from the Fruit Tree Care Training website at orchardpeople.
com. And I look forward to seeing you next month.
You've been listening to the Urban Forestry Radio Show on Reality Radio 101. To learn more about the show and to download the podcast where I cover lots more great topics, you can visit orchardpeople. com slash podcast. This show is broadcast live on the last Tuesday of every month, and each time I have great new guests talking to me about fruit trees, food forests, and arboriculture.
If you're interested in learning more about growing your own fruit trees, or just about living a more sustainable life, Go to OrchardPeople. com and sign up for my information packed monthly newsletter. If you like this show, please do like our Orchard People Facebook page. You can also follow me on Twitter at Urban Fruit Trees.
Thank you so much for tuning in. It's been wonderful to have you as a listener, and I hope to see you again next time.
Thank you for listening to the Urban Forestry Radio Show with your host, Susan Poizner, right here on Reality Radio 101.