Orchard People | Fruit Mummies with Kerik Cox

Have you ever found mummified and immature fruit on your fruit trees? Learn what's happening and how to prevent this using botanical sprays in this episode of the Orchard People podcast.

Our guest is Plant Pathologist, Mycologist, and Bacteriologist Kerik D. Cox Ph.D. of the Cox Program at Cornell University.

The host of the Orchard People radio show and podcast is Susan Poizner of the fruit tree care education website www.orchardpeople.com.

This show goes out LIVE on the last Tuesday of every month at 1.00 pm Eastern Time. After that you can download the podcast.

To tune in LIVE (and submit your questions to our expert guests!) you can:

Tune into RealityRadio101.com during the time of the live show
OR watch the livestream on the Orchard People YouTube Channel

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For premium fruit tree care education visit: https://learn.orchardpeople.com/.

About Cinnerate Fungicide: https://sym-agro.com/our-products/cinnerate-miticide-fungicide/

Chapters:

(00:00) - Fruit Mummies in an Historic Orchard
(00:35) - What are Mummy Fruits
(01:18) - Guest Introduction: Kerik Cox
(01:52) - What Cornell's Cox Labs Does
(03:12) - Causes of Undersized Fruitlets
(04:26) - Should You Worry about Mummy Fruits?
(09:53) - A Good Book about Growing Apples and Pears
(10:36) - Mummy Fruits on Apricot Trees and Environmental Stress
(14:57) - Can Fruit Mummies be Bacterial?
(15:59) - Fire Blight and Its Impact on Fruitlets
(17:14) - How to Prevent Fruit Mummies
(18:33) - Why Oxygen is the Best Fungicide (and Bacteriacide)
(19:12) - Why Does Correct Fruit Tree Pruning Deter Pathogens?
(21:38) - What is Fire Blight
(23:33) - UV Light Treatment to Prevent Fruit Tree Diseases
(26:41) - Protectiing Fruit Trees from Disease with Sanitation
(27:44) - Arborist Mulch and DIsease
(29:34) - Sponsor Messages and Announcements
(31:08) - Fruit Tree Care Tips and Advice
(33:07) - Discussion on Fruit Mummies and Disease Control
(34:03) - Covering Fallen Fruit Mummies and Leaf Litter with Mulch or Using Urea
(38:00) - Recommended Mulches for Smothering Pathogens
(40:19) - Should You Put Fruit Mummies in Your Compost?
(41:09) - Managing Peach Leaf Curl
(44:15) - Botanical Products for Disease Control
(51:21) - Can Botanical Sprays Harm Beneficial Insects and Wildlife
(54:15) - Integrated Pest Management and Spraying Tips
(57:23) - Conclusion and Upcoming Episodes

Want to make your own botanical fruit tree spray? Here’s a recipe to try. While this spray is all-natural, it can harm beneficial insects like bees, so be sure to spray at a time when bees aren’t active (early morning and late evening). Keep an eye out for bird nests and avoid spraying near them. And remember, you wouldn’t want to get this in your eyes or on your skin, so handle it with care!

Garlic Fruit Tree Spray

Garlic is known for its strong scent, which can deter many types of pests, from aphids to caterpillars and even some types of fungi.

Ingredients:

1 pound of garlic
1 gallon of water (rainwater is best)

Instructions:

Peel and Mince: Start by peeling the garlic cloves. Then, mince or finely chop them to release the essential oils. The finer, the better.
Simmer: Combine the minced garlic with water in a large pot. Bring the mixture to a simmer (not a full boil) and let it cook for about 20 minutes. This process infuses the water with garlic's active compounds.
Cool and Strain: After simmering, take the pot off the heat and let it cool. Once it's cool, strain the mixture to remove the garlic pieces. A cheesecloth or a fine mesh strainer works great for this. You want the liquid as clear as possible to prevent any sprayer clogs.
Dilute (Optional): Depending on what you're dealing with, you might want to dilute the mixture. A common approach is to dilute the concentrated garlic water with more water. This step is adjustable based on your needs and the sensitivity of your plants.
Bottle Up: Pour the strained, cooled liquid into a spray bottle or a larger sprayer for application. It’s ready to use!
Apply: Spray it on the leaves of your fruit trees, covering both the tops and undersides where pests like to hide. Early morning or late afternoon is the best time to apply, avoiding the hot midday sun to reduce the risk of burning the leaves.

Tips:

Storage: You can store the garlic spray in the refrigerator for up to a week. For longer storage, freeze it in an ice cube tray and thaw cubes as needed.
Test: Always test the spray on a small area of the plant first to ensure it doesn't react badly.
Reapply: After rain or watering, you might need to reapply, as it can wash off.

Creators & Guests

Host

Susan Poizner

Author, fruit tree educator, and Creator of the award-winning fruit tree care education website OrchardPeople.com.

What is Orchard People?

Learn how to grow and care for fruit trees with fruit tree care educator Susan Poizner of OrchardPeople.com. Discover how to create permaculture plantings, food forests, and forest gardens in both urban and rural settings. Meet experts on all aspects of comprehensive fruit tree care, including pruning, pest and disease prevention, fruit tree grafting and budding, and soil management.

Show host Susan Poizner, creator of the fruit tree education website OrchardPeople.com, is an award-winning author of three fruit tree care books and an ISA Certified Arborist. This podcast is the winner of the 2021 GardenComm Silver Award of Achievement for Broadcast Media: Radio Program Overall. Learn more and access archived episodes at https://podcast.orchardpeople.com/.

Learn more about Susan's books and courses at https://learn.orchardpeople.com/books.

One of my favorite orchards in Toronto is called
the Spadina House Orchard,
and it's on this beautiful historic property. It's a grand estate that dates back to the 19th century.
So it has a beautiful heirloom apple orchard.
And this orchard is never sprayed
with harsh fungicides pesticides.
So, sometimes the trees get sick.
And this year there were a couple of trees, the Baldwin, a Baldwin apple tree and a Tolman sweet apple tree.
And they had a lot of mummy fruits.
So mummy fruits are those little shriveled up, small fruitlets.
They can be on apple trees or apricots or peach trees.
these little fruits never grow properly and they shrivel up and sometimes they're fuzzy.
Now it turns out that is a sign of disease and it's the tree telling us that we really must do something to prevent this disease from getting worse.
And so that's what we're going to talk about in the show today. So we're going to talk about mummy fruits. and fungal diseases. And we're also going to talk about some botanically based products that can be used to prevent fungal diseases and other diseases.
So my guest today is Kerik Cox, and he's an associate professor at Cornell University.
Hi, Kerik. Hi. So Kerik, you're a plant pathologist, you're a mycologist, you're a bacteriologist, and you actually told me that enough about horticulture to get yourself into trouble. Is
that true? That's true. Yeah, just enough to almost make it work.
To almost make it work. So just briefly, tell me, what is it that you and your team do?
You've got this lab. You've got fruit trees. Tell me what you guys do.
Yep. So in a nutshell, what we do is we, do two things. We evaluate alternative management practices, which would include a lot of biological, Controls, horticultural controls, and some even, stranger alternatives, such as using light.
And that's what we do in apple and strawberry.
So, I have this image in my mind, you guys are running around with like diseases or something, pathogens, and you're throwing them on trees to make them sick, like
Yeah, most of the diseases will occur naturally. they're endemic, they're in the air, much like the, the mummies you talked about.
no one brought them in their present and usually on the surrounding area. And in most of our cases, with the exception of the bacterium fire blight, We just let the diseases come in and we manage them using alternatives and biologicals to see if growers could do the same for commercial production.
Wow. Okay. So there you are. You've got your big sick orchard and you're hoping for it to be sick. Whereas people like me want the opposite. We just want our trees to be healthy. But sometimes you go out and you see these little fruitlets on the trees. And like I said, it can be apples. It can be. Apricots, cherries, why is it that, what, what's happening here?
Why are these little fruitlets not growing to be a decent size?
Okay, typically two reasons.
One, there's too many little fruitlets and not all of them are getting enough nutrition and the tree knows with its hormone balance and genetics to Oh, that's just, we gotta, we can't have all of these. They're not all going to work. Let's get those few that are going to do good. And there may be some natural, we'll call it, death of the fruitlets or thinning.
The second thing, as much as you described, It could be an exogenous pathogen, or it could be something that's more innocuous that happens when little fruitlets are killed.
You can think of it as the runt of the flower cluster, if you will. And if there's a cold snap, let's say in, I don't know, April or March, It might kill some of the less ones that are more of the runts of the cluster and they will die and other junk will come in and colonize it.
Okay, so this is giving me some clarity.
So I understand that either it's nutrition, it could be they're just not getting enough food, the tree isn't getting fed enough, it could be a pathogen, it could be a frost, it could be environmental, something has killed these little fruitlets.
All right.
so there it is, and it's hanging in the tree.
I guess some of them may fall to the ground,
so is it intrinsically when I see a little dead fruit lit on my tree, is this necessarily should I worry or maybe it's just normal sometimes?
Yep. Okay. Good question. It depends on the type of tree. If you have a stone fruit and it looks fuzzy, maybe worry. If it's an apple tree, you're, I would not worry so much.
Unless you think it's oozing. The ones that are typically on apples will contribute a little bit to what we like to refer to as disease inoculum, which are the propagules of disease that are present in the orchard. And if they got too numerous, they might cause you problems at harvest. Now, if the squirrels eat all the apples off your home tree first, definitely don't need to worry about them.
They'll typically only cause fruit rots in apples.
The same with peaches, and cherries, and plums, and nectarines, and apricots, and almonds, should you have one. but those are, that's a little more aggressive of a pathogen that colonizes the stone fruit.
The apple ones are a little more weak sauce. They can cause damage to your trunk, and limbs, and cankers if pruned in wet weather.
And rot fruit at the very end, but they're not as, concerning initially, unless you get way too many of them.
Okay, so we got these dead fruitlets, and at this point maybe they're not fuzzy, but then they get fuzzy.
So once they get fuzzy,
what is that telling us?
What is the fuzz, the little ugly fuzzy little things?
The fuzz is fungi. mold specifically. You can think of some commercial examples of mold in bathtubs and horror films, or hopefully not your own home, or mold on a fruit in your refrigerator, or even mold in ventilation shafts like black mold. So those are the fungi telling you the fruit is dead, it's run out of nutrition, I need to make babies and get out fast, and I'm gonna make a lot of clonal babies, so to speak.
And that's what they're doing. And they will go fly around and survive or infect new fruits if they're ripe enough.
So this ugly fuzz is fungal babies. How can their mothers love them? They're so funny looking, right? you have no idea the mother spore. Yeah. Okay, so fuzz. So first of all, we've got a little email here.
We've got an email from Chris. Hi Susan, I did some research on this topic, very, interesting, good choice for a topic today. P. S. I missed the contests. Oh my gosh, Kerik, every month I have somebody, and Chris is this month's person, I used to do contests every month where people could win a book and a prize, and I think I might have to bring them back because I'm getting a lot of complaints, I'm getting an earful from people.
Wow. Well thank you, thank you Chris. hello to Susan Poizner listening in again from Barrington, Illinois, Does Dr. Cox have a book or information out about this topic? Thank you from Brita. Good question. Or a web page,
about mummies.
Well, and in general information, where first of all, where can people find out about you?
Okay. And where can people find out about mummy? mummy fruit. And by the way, Brita, because Brita asks, I plan to do an article on orchardpeople. com specifically about mummy fruit based on this podcast. So that hopefully will be helpful too.
That's exciting. mummy fruit. I haven't done a lot of this research since 2009.
So a lot of it has been done quite some time ago. Where would some of the best resources to find out about mummified fruit are probably on the shelf behind me, unless I have. Undoubtedly given them to one of my students. I'm gonna go pull over and grab a book.
Don't worry too much. Okay. In the meantime, while you pull, yeah, you can pull out a book.
Actually, I'll let you pull out a book. In the meantime, I want to say hi to some people on YouTube. We've got Jeff, Terry, and Toronto Homestead. thanks guys. Thank you so much for tuning in on YouTube. That is super fun. and we've got a question from Sarah as well. And we'll go back to the mummy fruit book in a minute.
Hello Susan. I'm not sure about how to post on YouTube for everyone. So I hope an email is okay. Yes, email is always okay. I'm Sarah from Southern Ontario. Quick question. Are you having trouble with the live stream right now? I want to know if it's my connection. Well, Sarah, we are on live stream, but I want to say to everybody, if you are listening to this on Reality Radio 101, of course you can email your question or your comment to info at orchardpeople.
com. That's info at orchardpeople. com. Always include your first name. And where you are writing from and we are so happy to answer your questions and great questions, Sarah. The live stream is happening. So hopefully by now you found it and Eric Lee is also on the line. Thank you, Eric, for coming on. Eric inspired this story.
Okay, so back to a book on something related to fruit mummies.
Yep, your best bet, if you're Apple, is probably the Compendium of Apple and Pear Diseases and Pests. I've written a couple chapters in it. There's also one on Stone Fruit as well. It's sold at the American Phytopathological Society's webpage, aps.
net. org. And that's where you're going to find your best information on mummies. That's not a heavily researched topic. Mainly, I think the more devastating the problem, the more books there are. Now, by comparison, I have an entire 300 page book on fire blight because it kills in two weeks. And that's why bacteriologist.
Well, and that's really interesting because, for a home grower, we see these fruit mummies and we either ignore them, which I've done in the past, and that was not a good, successful tool, successful approach. We had fruit mummies on our apricot trees years ago. And. I left them because I thought, oh, whatever, it's nature, they'll decompose.
And they were fuzzy and everything. The next year, both apricot trees had a lot more canker oozing goop coming out of the tree. So that year, when I saw fruit mummies, I cleaned them off and I pruned off the branches of that tree to, to get rid of all of that. I hoped the pathogen on those apricot trees.
Now, I will tell you that helped the following year. We didn't have as much of a problem.
This year, our beautiful trees were in full bloom.
We didn't cover them. When we heard that there was going to be a frost, it was just freezing and we thought it's okay. There was a frost
and it killed all the blossoms.
But not only that,
the, canker, the ooze and goop all over the tree went nuts in both trees.
So I'm just wondering if environmental stress
is something that can make these problems worse.
Absolutely, it can. And, your cankers are probably one type of fungus and your mummies are possibly slightly a different one.
Cold snaps and freezes can make a fungus that can do both mummies and twig blights and massive cankers. Now, the oozy goop, that's just the plant's natural response. It's basically, peach syrup or apricot syrup. It's just gel. And much like a maple tree that was wounded, but there is a nasty wood decay, fungal pathogen in there causing Serious damage and I think that's one of the things that even commercial growers forget That when you lose the entire crop and you're like i'm done and you walk away The diseases that occur from the damage due to cold mummies and cankers will just continue to explode if you ignore them for the rest of the year after throwing in the towel on production.
So that's something to keep in mind.
Whoa, well, that's incredible to know that it's not necessarily all one thing. Now, In this case, if we are to prune off, these trees are not looking good, and we have been pruning off all the oozy goopy branches, how much is left after that? I don't know. so, is there a time where you're supposed to say, okay, it's time to just cut it, call it quits?
Yeah, I would say sometimes, even for the homeowner or the commercial grower, once you get from the big branches to the main scaffolds of a peach tree, your, quad or, I can't do four fingers right now, but you get the idea. or if you're doing the V, if you get to the big scaffolds, it's almost worthwhile.
and then replanting, particularly in the case with apple. Once the major scaffold branches become damaged, and if you want to look for the canker, sometimes the ooze is a good indication. It will look more blackened than your traditional beautiful nut brown look to your stone fruit bark. If it looks more blackened or if the bark splits, which can happen even if you get very cold weather and very hot weather the next day, such as we're experiencing in the northeast.
It might be 75 somehow in February and the day before it was 25 or 10 and something like 28. And you're like, how did we get this snap? And that will break your bark apart and crack. And then all the things will come inside and I'm just rot fest. 2024. And then at that point, you throw in the towel.
Apricots are very challenging of the ones that are the most susceptible to cold injury.
Interesting. And I've also been told by, people who worked for extension services, that apricots and peaches, they've got a lifespan. It's about 15 years. And after that, you're going to be fighting off the bacterial canker, whatever else I guess,
can those fruit mummies, you mentioned that it's, like little fungus babies.
Can they ever be a sign of a bacterial disease?
Not typically in the stone fruit. the bacterial diseases will be more, your ooze won't be as gelatin. If you're on a stone fruit tree and you squish it, it looks like amber and really thick, and you can play with it like a gummy bear. That is your natural rune response.
However, if you're on a stone fruit tree, say a cherry, and there is bacterial canker stone fruit, and you're pushing on the bark, and it's very spongy, like a hard stress ball. Then you've got a problem with bacteria. apples will ooze and it'll look a little bit more like little tiny pine droplets on stuff.
In that case, you've got fire blight, and it's really bad. The same with bacterial canker. And you're right. Over the years, these things slowly build, until they're untenable and you're best off removing and starting fresh.
I'm starting fresh.
Okay, fire blight is such an interesting topic because fire blight, most of the diseases that you encounter in fruit trees are going to be fungally based.
Fire blight is bacterial and it's nasty.
As you said, it can take out entire orchards. I really encourage people, home growers,
to buy fruit trees that are resistant to fire blight just to make their lives easier.
But, so when If a tree with fire blight has a fruitlet that doesn't grow to full size, you're saying it's going to be, it won't look like the other mummy fruits.
Yeah, it might be more smooth. It might look a little bit like one, but it might turn a more translucent amber color. And then if that's the case, and if it feels sticky to the touch, that's just loaded with fire blight cells. Or, if you get to the middle of the summer, and everything looks cool, and droplets forming on your fruit, that means fire blight has ridden the, water slide straight to the fruit.
And it will get into the vascular tissue and move to the active growing tissues. Then you can tell at least the nutrients are going to the fruit, where you want them, but the fruit is loaded with more ooze, which is terrifying. Okay, so
let's talk about, and we hinted at this. fruitlets on the tree.
what, are your options? is it best to, as soon as you see a little fruitlet that isn't going to be full size to pull it off?
I would say, if possible, I'd say you could do it on a weekly basis and probably be fine.
so you're removing the baby fruits, the dead fruitlets, as you see them.
That
will also make your crop better.
So the tree is not wasting energy putting it into little dead fruitlets, instead it's only going to put it into the happy healthy fruitlets. So that's great. Pruning. Is pruning a response that's appropriate, and if so, why?
Yes, you can. I would say if you're trying to get rid of the fruitlets, some of them, particularly on Fuji and Cortland apples, can be very hard stuck.
And you might go out there and prune them. try to pull them off. I would just use a pair of heavy duty scissors or pruners if you have them and prune them off.
Now, if you have lots of these things, pruning your trees so that the canopy gets better airflow through it will probably prevent the fungal type ones from occurring.
Air is the best fungicide and bactericide.
I love that you said that in our pre interview and it just sticks in my head. Air is the best fungicide and bactericide. So essentially when we're pruning our fruit trees correctly, we are leaving so much air circulation. We are leaving so much room.
I know that sometimes newbies are Even arborists often feel like they want to, trim the outside of the tree, shorten all the branches, make it a nice round ball or shape it that way. But we're essentially going in and removing branches in the middle strategically, if you know how to prune correctly, in order to allow air to circulate inside of the tree.
Now, why is it that deters any pathogens. Okay. Why is that so helpful to have that air circulation in the can? Okay,
so all of the pathogens, whether it's a bacterium from fire blight that's in either in a bud scar on a stone fruit or on the surface of a flower or a fungal baby spore that has landed on susceptible tissue, all of them need water to live just like we do.
And with better and faster drying, the propagules will dry up and die. on their own. So that's why you want it more so. If you want a topiary, make a topiary out of something else. If you want a fruit plant, give it some air to breathe and protect itself.
and what is it that's breathing? and, is it like, Is it so that the leaf, so that the, yeah, so tell me about the science behind it.
What is breathing?
What will happen is the bacterium in this case, it needs a water droplet in order to do, to eat, just like we need to drink water. And it will also use that water droplet to sneak inside a wound on your plant. It can't move very much on its own, so if that bud scar or flower gets a water droplet on it and it stays there long enough.
That bacterium is going to roll down into the tissue and start killing. Now with a fungus. Spore, like an egg alien and an alien movie will germinate this long tube of mycelium and it will make an infection structure that will burrow into your plant and start killing it or rotting it. And then from that, it'll make more and more babies.
But if you pass air over that germ tube, we'll call it the little piece of mycelium that's infecting it will dry it up and it will die.
And so we've got, yes, oh my goodness, we've got air, and then it makes sense that sunlight, access to sunlight is also going to help because the air will blow away the moisture, the sun will dry it up, oh my goodness, which explains in the early years, the first thing I learned in order to take care of our community orchard where we can't use toxic sprays, was to prune them.
That was the most important way that we managed our trees and most of our trees, knock on wood, are incredibly healthy except for those two apricots which are not having a good day.
We've
got a question here from, is it Clyde? So Clyde asks, what actually is fire blight?
Fire blight Think of it more as a, it's a concept.
Don't try to think of it as an entity. It's a concept where the apples are being killed by a bacterium in hot, wet weather.
And it, we call it fire blight because it makes the tissue blackened. And in apples, it'll make a crook. In pears, the tissue will become very blackened. And what blackened is cell death.
Whether a spider bites you or a bacterium dissolves the cells, they turn black. And so, The fire blight itself is the action between a bacterium, the host, and its environment, water, sunlight, like you mentioned, and susceptibility of the particular plant species or variety that you're using.
And Clyde is, as well, what, fire blight is famous for, well, you see it in the youngest, It's like little sprouts.
So the sprout, the new growing sprouts, they look all happy. Then all of a sudden they turn into a crook and they look like they're burnt up from the edge. And then it, I guess it moves into the tree and that's exactly
right. Yep. It wants nitrogen. Like we might want, some of us might want to eat meat or if we don't want to eat meat, we still want amino acids and proteins, whether it's almonds or whether it's mushrooms or whether it's tofu, the fire blight wants that well.
And those active growing tips. are the easiest for the bacterium to kill, and they have the most nutrition. So it's gonna gobble, and then it's gonna get into the vascular system, like a bacterium in our bloodstream, and it's, oh, I'm going everywhere, and I'm going straight for the fruit and all the nutrition.
That's why it loves those young tissues. So the younger and more succulent and active growing your tree is, the faster it will die.
Oh, goodness gracious. Okay. So, I, want to, there was one more point that you made that I want to pick up on and you were talking about UV light. We were talking about sunlight is important for drying the branches.
So how is, I know, you guys are testing UV light. How does that work in an orchard environment? All
So I just did this last night on Memorial Day because we had a wonderful rainstorm. So when it does rain, That's when the bacterium is going to roll in. That's when the fungus is going to use the water to get in.
And that's our opportunity to use something like UV light. So what UV light does The spores and bacteria multiply very fast. They'll split every 20 minutes, pop, or spores can produce lots of them, and there's numbers. And so they need to divide and multiply their DNA. And what the UV light does is it comes in there, pops the DNA helix apart, and causes two of the bases in it to become mismatched.
This prevents the organism from growing. And then our light can come in and dry them up the next day as they become statically wiped out. And you'll see this in medical facilities. You'll see it in water treatment plants and fish tanks like my reef tank. That's how we keep all the bad protists under control because they all swim to the light.
Now the fire blight and the fungus, they're germinating and they get zapped and they're trying to grow this tube and the UV light breaks it down. And it stops it from growing and then it dries up the next day and it perishes. And so that's one of the things we like to do. No residue. It looks like there's opportunity in grape, powdery mildew particularly, strawberry, and apple.
It's becoming more widely used and it's often used in cover production agriculture. up on the border into Canada where they're doing all the really interesting greenhouse stuff.
Okay, so I have this image of you with some sort of ray gun, like a UV head gun. Is that what it is?
It's it's a covered over the row unit.
So imagine I'm pulling a tunnel behind a lawn tractor. And the tunnel is only nine feet long. And it looks like I'm just going over the row and inside it is a reflective series of lamps that put out just the right dose to damage the organism, but not the crop.
So you'll be running this, it rains, then you and your team go out there with this tractor and you drag this kind of tent over the fruit trees. Yep. Clean them up. Whoosh. No problem at all. Wow. Yeah. Probably not too helpful for a home grower though. Interestingly, they do
make lights and If you're a very expensive homegrowner, sure.
like I said, there are different options for different sized operations. So, I have it in my fish tank at home, and it's a 15 bulb that I run water through off Amazon. com. Now, there are handheld units that one could do for this, but between the both of us, I think the sanitation is the best practice for home growers.
You're not trying to do 300, 500 trees. You're trying to like, I'm going to manage a couple. And
exactly.
And so let's specify what does sanitation mean? We want to prevent fruit mummies. So what is that going to look like? Whether we're growing peaches, apples, apricots, cherries, how do we, how are we sanitary with our trees?
So my number one suggestion is if it's not making you fruit and it looks dead, remove it from the tree, whether it's a branch, a piece of wood on the side of the tree, a canker, a shoot, a mummy, all of that is basically a reservoir for bacteria and fungi to come cause you trouble.
Okay, so pruning is really important.
Leaf litter as well. Leaf litter, removing the leaf litter, removing the mummy fruits as you see them. What about mulch?
so even if you're like, I can't rake up all this stuff, I'm going to mulch it. a lot of the pathogens like to hide in the sod and grass and in the leaf litter. And if you're like, well, I'm just going to mulch it.
you're fine. You're good.
Okay. Oh, my goodness. Okay, so mulch is an interesting topic.
Last month, I think it was or the month before we did a show about using arborist mulch in your orchard or around your fruit trees. And we understood from that wonderful interview that the beautiful part of arborist mulch is that it contains living tissue as well as not just the fruit.
So it's actually adding nutrition, but when you get arborist mulch, you may not know whether the tree had some fungal or other diseases, and that may come in the mulch as well. With your mulch if you care a cat a backyard fruit tree.
Yeah, would
you bring in arborist mulch?
we've brought in some to some of the better things that we've seen people bring in our compost Because the microbes and compost are not the same ones that are going to attack your tree And if you can avoid the woody ones, I think you're gonna be better off if there have other type of compost under a tree.
I knew a person who did biodynamic. They did their hands. They used, manure from the cow fields to fertilize and manage their inoculum by smothering the fungal propagules with it and seemed to work really well. With little to no need for anything, even biocontrol.
Wow. Well, we're going to talk, in a minute we'll have a few words from our sponsors.
And after that, I want to talk to you about the types of sprays that you are testing that are made in, made purely of biocontrol. Botanical products like cinnamon, garlic. you are testing stuff that's going to be used in commercial orchards. And I find that fascinating that, even commercial orchards are now going towards the more natural products.
So are you okay staying on the line for just a minute or two? yeah.
And then we will continue this conversation after that. Okay, super. You are listening to Orchard People, a radio show and podcast brought to you by the Fruit Tree Care Training website, orchardpeople. com. This is Reality Radio 101, and I'm your host, Susan Poizner.
And we'll be back right after this break.
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So on the show today, I've been chatting with Kerik Cox, associate professor at Cornell University. And we've been talking about fruit mummies on fruit trees. So now often these little shriveled up fruitlets are the result of fungal diseases. How do you control those diseases?
That's one of the topics we're going to be talking about next. I would love to hear your questions about fruit tree diseases, and we have this wonderful expert with us today. So to send in your question by email, just send an email to info, I N F O, at orchardpeople. com. That's info, I N F O, at orchardpeople.
com. Info at orchard people. com and do remember to include your first name and where you are writing from. Now, if you are watching us on the YouTube live stream, welcome. I'm so glad you're here with us. Tell us where you're tuning in from in the chat box and ask your questions there. And I really look forward to hearing from you.
Okay, Kerik, so we've got a couple of questions that came in during the break. One of them is Eric wants some clarity here. He's saying, should you cover the leaf litter with mulch? Will that stop the pathogens? Perhaps, if the fruit mummies, these little fuzzy mummies, fall to the ground, and if you put mulch on top of those fuzzy fruit mummies, will it kill them, or will they like it?
So it's a good question. So, two things happen. The fruit mummies on the ground and the leaf litter, what they want to do is survive and make it to the spring when they'll mature and they can shoot spores up into the canopy of your tree. If you cover them, they will attempt to shoot and immediately hit a wind, even if they do not degrade.
Now, if your mulch is microbially active or highly microbial active, it will decay the mummy or the leaf litter to the point where the fungus doesn't have anything else to use. You are basically out competing it by putting a whole microbiota on top of the tissue that you want to get rid of. So one of the things that we do in commercial orchards is we actually put feed grade urea prills on the ground.
And that urea will enhance the microbial communities of the soil and eat the leaf litter for you like a compost pile.
I have heard a lot about urea. I don't really understand what it is. can you tell me a little bit about it? You buy it?
It's, typically it's available, I think, for feed. And, it's a really simple fertilizer.
So it's putting a lot of nitrogen, some nitrogen on the ground. And, now in April, which is a little tiny thing that kind of looks like a something you put on your sidewalk to melt snow, looks like that. And you will put it out there. You'll mix it into a solution. You'll put it down and all the other microbes, the natural microbes that are in your soil, oh, it's a free buffet.
Let's eat it and use this extra nitrogen to break down organic matter. Sometimes you might have heard of people putting fertilizer on a stump. that's to enhance the microbial communities of the stump, give them the extra boost they need to decay recalcitrant organic matter like leaves, sticks, and mummies, and other hard pieces of semi woody type tissues.
So it really helps microbial
degradation. Is urea acceptable in an organic orchard?
That's a good question. It depends on how the urea has been obtained, I would imagine, and marketed. I've had a lot of organic growers tell me, well, we haven't gotten in trouble for using it yet. the other thing you can do is just put out natural fertilizers.
We'll essentially accomplish the same thing. chicken manure, the person who is using manure from their cows, all of that type of stuff was, essentially, anything you use to organically fertilize will probably do the same job. You're putting that fertilizer out to the microbes so they can break down the disease inoculum tissue for you.
Not only that, you're smothering the tissue that could be causing an infection later in the spring.
just to clarify, in terms of the chicken manure, usually we're told it needs to be aged. Yeah, it needs to be aged or any manure should not be put on fresh on tree roots because it can burn the roots. Am I right there?
Yeah,
you could do that as well with urea, pearls at the, rate that they recommend in a commercial orchard. It doesn't seem to harm apples. are usually the roots are underground and, the graft union is a certain distance this part where it's grafted to the rootstock is, the roots are always typically underground.
If your roots are exposed, that could, be all kinds of problems with that particular situation.
I love this question from Gail. I don't know where Gail's from, but she, says, Hi, Susan and Dr. Cox, if we do, in fact, use mulch, what is the recommended kind? So you were talking about mulching with compost.
That's what we do in our orchard. We bring in compost.
Yeah.
But a lot of people will either on top of the compost or instead of compost, mulch with bark chips, which you get, they call them wood chips, but they are just pure bark.
are equal, are they equally as effective if you cover the fruit mummies with the bark chips?
I
think they're probably going to be just fine for smothering, the bark chips. I put wood chips over our Gala apples at home and they seemed fine. I think anything you can use to cover it. Now, a lot of times with the hardwood mulches, you might see more interesting fungi, but the typically the fungi that lives on wood chip mulches are natural wood decay microbes, and they don't have the same battery of warfare tools to cause disease.
They're just like, I want to digest cellulose, and I want to digest lignin. And that's pretty much all I want to do. And I might make some cords and go forge out and find some other rotten wood. So typically they're okay. you can cause pH changes depending on what type of wood chips you get.
Now, if you're not mulching at that time of year, what we do is in the fall, we rake up everything around our trees.
We just rake it up, we clean it up. So, that way you don't have to bring stuff into cover and smother. Just take it away. You see something sick, whether it's on the tree or on the ground, clean it up and take it off the site. Don't put it in your compost, right? If you put it in your personal. You can do that.
As
long as your compost is one of those covered ones and you don't leave other leaves on top of it. From other plants? Yeah. Raking is good. That's the other option growers will use. It depends on how much time they have and how much labor. If you're five thousand hectares of apple, you might apply urea.
If you're, and it doesn't have to be a lot, it's just enough to get the microbes going. You're not trying to cause algal blooms in the Great Lakes. You just want to let the local communities eat. So you're not over fertilizing or anything like that. And the apples can't really use it. But raking is the other one.
Something that I keep in mind, the reason I don't put any of this stuff on our, compost is you could be raking up apples that have, maggots in them. And I wouldn't wanna put that in my compost 'cause they'll just, over winter
they would. So Yeah.
But then the apple won't break down and cause the developing larvae to die.
No, they'll keep coming back. , from what I understand we'll be doing. Some entomology, an entomology web winner soon, so I can clarify that, but I'm pretty sure as much as possible. I try to take those pathogens off the site, but Yeah, that's me being very safe.
I think that's
the best plan. Off the site is always best.
Yeah, take it away. It's nasty stuff. Anyway, sorry, it's not very nice. Everybody deserves to put their place in this world, just not in my fruit trees.
we've got a nice question here, an interesting question from Toronto Homestead. My peach trees caught peach leaf curl this year.
I don't want to make them worse. Is it safe to prune them right now, or do I have to wait for them to go dormant?
okay. It is safe to prune them in cool, dry weather. So like in Geneva, we're, God, baby high 20s and no, no rain predicted for the week. This would be the week to do it. cool, dry weather. If you can, if there's no more thunderstorms for the rest of the week, you can do it now.
What you don't want is hot, wet, prolonged weather when you prune. And that's essentially what you're doing when you take it into the winter as you're pruning it in the winter where the fungi have no chance of growing because it's too cold and they need heat to have their metabolism moving. So cool, dry, you're probably fine to do it.
Peach leaf curl, unfortunately, is one of those diseases that's best managed with bud break applications of some sort of copper fungicide. Otherwise, you might be living with it.
Yeah, so, but if Toronto Homestead does prune out the infected branches, there's a chance he'll slow it down.
Yeah, I would do exactly what you said, prune them out, break them up.
Put them in a truck, take them far away and compost them from other peaches. There are going to be obligate to the peach. It's not like you're going to get peach leaf curl on, rhododendron or something of that nature.
And, for those people who, live in areas where you can actually burn branches or bury them, is that often an effect?
You can do
that, but you're doing the, you might 12 cylinder car and fire it up at the same time. you're putting carbon monoxide into the environment. If you could take them offsite to the woodland forest compost pile, then that's the better place.
Well, and, here in Toronto, they do collect, leaf litter and they have huge, I know because I used to work as a gardener for the city of Toronto, huge, composting piles.
So hot, steaming hot, nothing will survive there. So that's a good place to send it. Okay. Okay. Eric sells, says, sorry, Eric says, is cedar mulch microbally active. Cedar mulch where we've just got the bark, could it be microbally active if it's made of dead bark with no living tissue in it?
Yeah, sometimes.
cedar is a very recalcitrant wood when you think about wood rotting fungi and whatnot, but there are some things that can do it. A lot of the really stinky woods, we might call them cedar, pine, that might smell really good are there because they're have natural antimicrobial phenolic compounds that will keep them down.
I think if I were to take some cedar mulch, throw it on a petri dish, I would see all kinds of microbes all over the place. But I think it would be one that's generally lower on the totem pole for having lots of microbes in it, particularly the stinky ones, pine, cedar, the very pungent, trees, we'll call them.
Well, and that links nicely into what we're going to be talking about next, which is these botanical products, which are also stinky. Garlic, cinnamon. What is it about stinkiness that seems to turn off pathogens?
Yeah, a lot of the, compounds we're probably detecting as stinkies because they're hitting our receptors in a very negative way.
They may actually be damaging. Some of our stuff, if I were to take a spoonful of dried cinnamon, throw it in my mouth, I would burn all of the stuff in my throat because a lot of these, the oils and stuff that are present in these natural compounds or various phenolics and things are, Are sort of cell damaging organic, biomolecules.
And for us, they, they may have, fragrant smells, but they're actually to repel. They're not always meant to attract us. You can think of wasabi, while we've developed a taste for it. some of the original lines were deterrent to caterpillars and herbivorous feeders. So in the same with the cinnamon tree, it probably developed these defenses to keep things away.
Same with garlic. And as a matter of fact, we like a little bit of burn, or a little bit of stimulation as we're eating food. But the same materials that stimulate will damage and break cells, particularly on really low defense. we have skin, we have The fungi spores just have a thin cell wall and the bacterium even less.
That's why light can kill them. And then that's why an oil containing, various cinematic compounds will just be able to wipe them out as well. Peppermint is another one as well. yeah, all of the tea tree, neem oil, all of these different oils from natural trees are, slightly damaging to cell tissues.
Make some great for antimicrobial on our body. If you have a tea tree oil, peppermint soap, like I do, does wonders for, getting rid of like little cuts and scratches over time.
So what you're doing, you and your team are out there in orchards, and you're trying to, you're testing sprays now.
Yeah.
Ten years ago, the sprays probably would have been made out of very harsh synthetic chemicals.
Yeah, Yeah,
like Kaptan, Mankozeb, sometimes very highly specific, gene targeting, Antifungals, but they're not very harsh, but yeah, some sulfur and, copper, all of these different things. It's just that the, I think the cinnamon and the thyme and stuff are a lot softer on, the environment overall.
Now, that being said, I would be much better off getting, sprayed in the face with a synthetic single gene targeting fungicide than cinnamon oil. Much you've seen the people on the social media eating it as a challenge. that type of stuff. It is generally biocidal. It just doesn't have a devastating microbial fate in the environment.
Does that make sense? It makes sense. That makes sense. I think we'll come back to that in one second. We've got a great question from Farzad. Is it okay to apply hydrogen peroxide to control fungi or bacteria on the bark and or leaves?
Well, that's a great question. One of the alternative practices, UBS EPA calls them, Is concentrated hydrogen peroxide and peroxidic acids.
that one feels the worst if you get it on you of all the materials I ever speak. But and actually I think the Department of Homeland Security monitors how much we have, but it's organic approved. And it has labeled uses for that very purpose. There are several products, BioSafe, I think is the company that makes them, that are formulated to not damage your plants, but to damage the microbes on them.
Now, compared to your oils, they will go away very quickly. The oils last. if you get a perfume that's more oil based than alcohol based, you'll smell wonderful for a longer period of time. You'll get more residual control. With an oil. However, it's sitting on your plant longer. So you have to weigh the pros and cons of each type of approach.
So give me a little summary of the products that you're now testing and are they available for homeowners as well? So what, let's start off with the products you're testing right now.
Well, let me test a lot of different products. We test time products, we test cinnamon products, we test antimicrobial fermentation soups, cinnamon products might be Cinerate, Cinaction, TimeGuard is another one that we test, and, double nickel, and serafel, or these are antimicrobials.
We even test something called agraphage, which is bacteriophage, like they might treat MRSA in humans. It's for the plants, and it's for fire blights. We test that, and then we test phosphorus acid salts, which are actually, sound terrible, but are fairly innocuous. And we even test things like the hydrogen peroxide, and we have tested garlic oils and stuff in the past.
those smelled so bad. That, I don't want to test them anymore. and then we put in the positive and negative control. So we'll always be the big stuff in there to let you see relative. I can do it because I can be just as good as product X, Y, or Z, maybe using a different set of, rules and application time.
So those are what we test and of course light.
And so on the whole you found these, botanical base sprays with garlic though with smelly, yeah, with thyme, the herb thyme. with cinnamon. Have you found them? As effective as the old time highly chemical sprays? Yeah,
so that's the great question.
So, if your tree is big and bushy, the topiary, they will do a miserable job, because they need that extra push. If your tree is a high density, super spindle, fancy orchard, where your tree basically looks about as thick as a broom handle and has four or five shoots from it with great air passage, Yeah, I think it'll work pretty well because you can use that fungicide to enhance their ability.
And it's the same thing as a homeowner. If you're making your own botanical based spray and you're pruning correctly so that you've got lots of air circulation, it's working with the herbs or the botanicals. And the, the, pruning, that can be a good team. Now, I know that I will be putting in the show notes a recipe for garlic spray that people can use on their fruit trees.
Yeah, give it a try. So when I put up the, the video version of this show on YouTube, I will include that recipe. I would love to hear in the comments on the YouTube, video from anybody who tries the spray. Does it work for you now?
should we be concerned about insects? Do we want to be spraying garlic or time or cinnamon on top of, honeybees or beneficial insects or anything like that?
Yeah, absolutely. The problem is, if you go spray out during the middle of the day when the bees are pollinating, Just like me getting sprayed in the face with garlic oil, the bee does not want to get sprayed on its more tender body with this stuff. And there also may be birds nesting in your tree. At Cornell Agrotech, we have, marked all the bird nests with flags and stuff like that, so our team, goes through and we make sure to just we're not gonna do that tree because that's where organisms are living or we even have one in our parking lot some Killdere that are like nesting and like we have all marked off to the side And the same thing too.
We don't like to spray during the middle of the day one. It's too hot and miserable To the bees are out. And so when they go in the evening, that's the time to typically, to do these things. even if you're trying to manage wasps or something like that, just wait till they fly back in then.
Yeah, then you don't want to spray them while they're active and doing all of the good natural pollination and that they can do.
So when I go out to spray my orchard, I'm only really spraying with, molasses, and, fish oil, like fish essence and things like that. So I don't wear gloves. I don't wear goggles.
I don't wear whatever. I smell like fish afterwards. But is it the same thing if you're using a cinnamon based spray, like that commercial one, Cinerate, or whether you're creating your own garlic spray, do you need to protect yourself as well? I, ten.
I tend to because the oil is gross in our hair. many of the products that we use don't require us to use Tyvek, but I just buy myself Tyvek suit and goggles, mainly because I don't want to get the oil in my eye.
regardless of what, even if it's white mineral oil that It's another thing that's out. A lot of the oils will also be effective against insects because they smother them. They respire through their carapace, then you're going to be clogging all their pores and they're going to die. They're quite good early on in the apple season, just as a thing against scale and other things of such as that nature.
So oils are a part of an insect program as well. So, you don't want them clogging your pore. You might get, acne and breakout stuff like that as well. So I cover up Sometimes we wear the most protection for the botanicals. just if they're that hydrogen peroxide stuff, you better believe it.
I'd have a big stripe of white down my hair in no time if I didn't.
All it takes is
the wind to change and then, you've just put peroxide in your hair and now you've got a cool new haircut, like on the front cover of a Hair dye box or something of that nature.
and, finally, in my mind, integrated pest management, which is, has been developed over the years as a way of making our sprays and treating our trees, just making things safer for humans, for our planet, for our trees.
And a big principle there is you don't spray when you don't need to spray. Is there certain times of year that the botanicals are more useful, or are they just something you do every week, just in case?
Okay, so one of the ways that we've been able to make them work is to use disease forecasting models.
So I worked over the years with the Northeast Regional Climate Center, and we have models that will forecast Oh, this is the time. The risk is high. Use it. And that's one of the things, aside from using sanitation and horticulture, has really allowed us to take the next step in using these models. There's models for fire blight.
There's models for apple scab. If you don't have a model, what, one of the things that we're actually evaluating in our peer reviewed research is like, what if I just use my weather app and see when the next one inch of rain is coming? That's the thing. Yep, that's, excellent. If it has a residual, let's say an oil, we'd want to put it on before the big one inch of rain.
Now, if it's a hydrogen peroxide that's not going to last, but it's going to come in, kill, and clean the leaves, you want to put that on immediately after the rain. And that's why I went last night, because UV light doesn't leave a residual, but, oh, I went in right after the rain, and now if the things are germinating, I'm going to burn them out.
Same with stuff like bicarbonate. it's another really possible, potassium bicarbonate, it's another fairly safe. a lot of these things can burn you, but they have no environmental persistence. And that's why we really like them for reduced impacts on the environment in the long term.
Wow, Kerik.
I feel like I have learned so much in this show. I it's already three minutes. Our show is going to end. Where did the time go? thank you so much for chatting with us. can you tell us again? What is a website if people want to find out more about what you and your team are up to?
Oh, yeah, I'm gonna try to open it.
Here we go. It's, oh, can I paste it in the Zoom chat?
you can paste it in the Zoom chat and I will put it in the show notes to make sure people know. Let's see if I can find it. It's Corkslab, right? Yeah,
that's right. I'm clicking on it right now. Here it is. Yeah, it's got a really weird name like blogs.
cornell. com. so that's why I'm gonna just post it in that, Zoom chat for you. it's logs. cornell. edu. coxlab and then you can see about disease forecasting newsletters. It even has a link to my, my literal disease forecasts for the week, that we do as well as other topics on fire blight and whatnot.
Well, thank you so much for coming on the show today. I really appreciate having you. Hope you had fun. Okay. Bye for now.
Well, thanks everybody for listening. That was an interesting episode, wasn't it? so I'm Susan Poizner. This is Orchard People, and we have another show coming up next. month with another great topic.
But in the meantime, if you want to listen to this episode again, and I don't blame you if you do, because there was so much information, you can go to, orchardpeople. com and click on podcasts and you will soon be able to get the recorded audio version of the show. But here's what's really fun. Kerik has shared with me a whole bunch of fabulous pictures of fruit mummies, all different types.
I'm going to edit them into the video version of this episode, and it's going to be on the Orchard People YouTube channel. So if you want to watch it again and really see pictures, what does fire blight look like? We discussed that. What do fruit mummies look like? You will be able to hear us talking, see us talking and see images of everything we're talking about.
And finally. Why not sign up for the Orchard People Newsletter? I will every month tell you in advance what we're going to talk about on the show, and I'll also share really great articles about things that you need to know, if you're growing fruit trees, whether you're growing them at home, whether you're growing them in a small orchard, I really want to share with you all the ways that I'm learning about how to protect our fruit trees and help them to be the trees they're meant to be, healthy and productive.
So that's all for now. I hope you guys will join me again next month when I'm going to dig into another great topic. I'm Susan Poizner and I'll see you next time. Bye for now.