Orchard People | The Sex Lives of Insect Pests & Fruit Tree Irrigation

Welcome to the Urban Forestry

Radio Show brought to you by

the Community Orchard Network.

In this monthly radio show and podcast,

I’m going to take you on a journey.

We’ll learn about fruit

trees, permaculture, food

forests, and so much more.

So if you’re a gardener and enjoy growing

your own food, if you love trees and

especially fruit trees, Or if you’re just

interested in living a more sustainable

life, you’ve come to the right place.

I’m Susan Poizner, your host for today.

So get ready, roll up your sleeves,

and let’s dig in to today’s episode.

Hello and welcome to the Urban

Forestry Radio Show with your host

Susan Poizner.

Right here on Reality Radio 101.

To contact Susan live right

now, send her an email.

In Studio 101.

And now,

right to your host of the Urban

Forestry Radio Show, Susan Poizner.

Hi everyone, and welcome

to the show today.

You know, when you’re growing

fruit trees, harvest time is the

most exciting time of the year.

There is nothing like organic

fruit picked fresh from the tree.

But what could be more disappointing than

harvesting the fruit, only to discover

that someone else got there first?

Now I’m not talking about human bandits.

I’m talking about insect pests.

Those little bugs and moths that

nibble on our tree’s leaves and

fruit and lay eggs under the skin.

Now, fresh organic fruit just

doesn’t taste quite as good.

When there’s a worm or

a maggot hidden inside.

Now in the Ben Nobleman Park

Community Orchard in Toronto our

approach is to use orchard socks.

Orchard socks are nylon sockettes that

we slip onto the baby fruit and just when

the fruit is no larger than a nickel.

As the fruit grows the sock expands.

All the while protecting that little

fruitlet from insect infestation.

Now that approach works if you

have maybe ten fruit trees, or one

fruit tree, or twenty fruit trees.

But if you have a thousand

trees, tying on orchard socks

will be quite time consuming.

So you may consider investigating

other non chemical approaches.

Today, we’ll talk about some of those

approaches with my first guest, Dr.

Gary Judd, an entomologist who has spent

a lot of time studying the sex lives of

insect pests and learning how to use this

information to protect our fruit trees.

Then later in the show…

Is there a wrong way

to water a fruit tree?

The answer, believe it or not, is yes.

In the second half of the program

today, I’ll talk to Chuck Engels, a

fruit tree expert from Sacramento,

California, about the do’s and don’ts.

of fruit tree watering.

And I think we’ll all be pretty surprised

at how little we know about this

seemingly simple fruit tree care task.

But first, the secret sex lives

of the fruit tree insect pests.

Now on the line I have Dr.

Gary Judd, an entomologist from

British Columbia’s Summerland

Research and Development Center.

Dr.

Judd, welcome to the show.

Yes,

good afternoon.

Thank you for having

me.

Mm hmm.

It’s a pleasure.

Can you tell me a little

bit about your work?

What is it that you do?

Well, as you introduced

me, I am an entomologist.

And my specialty is in chemical ecology.

And specifically in that, I examine

the mating cycles of insects and

the chemical communication signals

that they use to find each other.

And those signals, they come

from plants that attract insects.

So, chemical ecology is what I

am.

Hmm, well let’s start from the beginning.

Pests, what kind of damage can

they do to our fruit trees?

Well, in True Fruits, we normally

classify pests into two types, generally.

Direct pests and indirect pests.

Now, an example of a direct

pest would be codling moth.

And direct because the caterpillar

feeds its way into the centre

of the apple and destroys it.

Or in southern Ontario, Toronto

area, you might have a pest like

apple maggot and the maggot…

crawls its way to the center.

And then we have pests that are indirect.

These could be things like

leaf rollers that feed on the

leaves and surface of the fruit.

So the oblique banded leaf roller would

be an example of an indirect pest.

So, okay, so we’ve got these kinds of

pests, and they are ruining the harvest.

So what exactly was the typical, maybe a

more, can I say, old fashioned approach

to preventing pest damage on fruit trees?

Well, ever since, since introduce

Used apples, uh, came to Canada a

hundred years ago in the Okanagan.

Um, we’ve been controlling insects

primarily with some sort of toxic spray.

And some spray that would either kill

the eggs or the young caterpillars

before they entered or fed on the fruit.

And that’s the classical way that we’ve

controlled insects for a hundred years.

And, and what’s the downside of that?

I mean, if it works, it works.

Well, it

works.

Yes, it works.

But, um, those toxins have indirect

effects on a lot of other organisms

in the orchard environment.

They cause a number of secondary problems

by, by killing beneficial insects that

help us control those indirect pests.

And generally they, um, they’re just

not good to consume in large quantities.

You have grower and worker exposure to

these toxic materials as they apply them.

So, um, You know, environmental

consciousness is given us a reason to

believe these chemicals are just better

off not having them in the environment.

So if we can find

alternatives, that’s, that’s

our aim.

So, okay, a different approach

of actually looking at the

mating habits of these pests.

What’s the history of that?

Um, you know, when did

people start to consider?

Well, maybe there’s a

different way to do this.

Well, the first pheromones, uh, the sex

pheromones for insects were discovered,

um, in, in about 1970 in the case of

the codling moth, and so, um, we’ve

been considering, uh, this use of

these, these chemical signals, these

sex pheromones, for at least, uh, a

better part of 40 to 50 years now.

Okay, and what, what were they trying to

do at that time, in those early years?

Originally, the first, uh, the

first sex pheromones that were

identified, these, um, let’s take,

for example, the codling moth.

They’re shown to attract the male

codling moth in very large numbers, in

very small amounts of these chemicals.

I mean, uh, hundreds or thousands

of a gram is all you need.

And they attract lots of males, and

so we put them in traps, and our

intention was to try and trap the males.

And we thought, naively, that

we might be able to control the

insect populations by reme…

Removing the male insects, so male

removal was sort of, or mass trapping

of males was our target of using

these pheromones.

Well, that makes a lot

of sense, doesn’t it?

If the males are dead, then the

females have nobody to mate with

and your fruit trees are protected.

Yes, that,

that was the supposition and that was the

hypothesis we were trying to test, but

as we stood, studied the insects and we

realized that a male insect might mate

with several females, um, it takes a very

few males to mate with a large number

of females to cause damage to your crop.

So it’s very difficult to control

100% of the males and remove them

before they mate with a female.

So that approach was somewhat naive

and really hasn’t been that effective.

Hmm.

So, uh, what happened next?

I mean, I know that if anybody

has, uh, you know, gone to a Yupik

orchard and wandered around, you

do see these pheromone traps.

Are they the yellow sticky paper?

Is that what the pheromone, or what

do the pheromone traps look like?

Entomologists have employed

lots of different traps.

Some of them are based on chemicals

like sex pheromones, these signals,

and others might be based on color.

So you might have a yellow trap

that attracts certain flies like

apple maggot or cherry fruit fly.

So entomologists have tried a variety of

different traps, but let’s specifically

talk about the sex pheromone traps.

Now the original, one of the most

consistent uses of them, and you

still see it and it’s still used to

a large extent, is to tell the grower

Uh, that the insect is active in his

orchard, when they’re there, what

numbers, and where they might be.

If you have, if you could well imagine,

if you had a hundred acre orchard, the

insects are not necessarily everywhere.

So the traps could tell you what

part of the orchard they were in,

and when they were most abundant.

And so that knowledge of the

seasonal life cycle, the ups

and downs of the population.

gives growers a good idea of when

they might spray their insecticide.

So, if they had to use insecticide,

they could use much less, and it

would be properly timed and properly

targeted.

Hmm.

So, in fact, if they only have the pests

in one part of the orchard, they may

not need to spray the other part of the

orchard.

That’s exactly right.

And that those are the kinds of techniques

we call are generally called integrated

pest management techniques, and they

became very popular after Rachel Carson’s

book Silent Spring and into the early

seventies, we started to develop these

IPM techniques, and they still are being

developed and refined consistently.

And is there evidence that they work?

Well, there’s very good

evidence that they work.

We have minimized the use of pesticides

and allowed greater protection of

crops with far less insecticides than

we were using 25, 30, 40 years ago.

But we as entomologists want to keep

pushing the boundaries and so we’ve

tried to use non chemical approaches to

remove all chemicals from the orchard.

And we’ve been somewhat successful with

that in British Columbia in particular.

So tell me a little bit about

where, where you went from there.

You weren’t happy with just this idea

of putting out the pheromone traps

and, uh, in order to discover where

the pests are and then spray them.

Uh, where did you take it from there?

What, what year was this?

Yeah, the, um, well, my career started

in tree fruits, uh, in, in 1989 here at

Summerland after moving from southern

Ontario, um, and That was the time,

um, we were starting to investigate

the possibility that we could use

these sex pheromones not to trap the

males, but to simply confuse the males.

Okay, and so I’ll give

you a little descriptor.

Um, we can synthesize the natural

pheromone in the laboratory.

That synthetic pheromone then can be put

in a small device that can be hung in

the tree and it can release sex pheromone

over the course of an entire season.

And if you have one of those, it

works quite well to attract…

The insects to that one lure, but if you

put a hundred of these or several hundred

of these lures throughout the orchard,

what it does is it creates a fog is the

best way to try and describe it to the

average person is we create this fog of

pheromone throughout the orchard canopy.

That then confuses the male moth, so they

don’t know where to search for the female.

So the, the natural signal becomes

camouflaged, if you like, and the

synthetic signal is very prominent.

They respond to that, and that, that

camouflaging effect or confusion effect

is something we collectively call mating.

disruption.

I have this image of the male insects

flying around back and forth looking,

you know, going towards, I guess it’s

the smell or is it a smell based thing?

They’re going towards the smell and

it’s like, Hey, where are the girls?

I can’t find any girls around here.

And then they fly somewhere else.

So is that it?

They’re just flying back and

forth wasting their time.

That’s

precisely how the mechanism starts,

and again, in our early days,

we thought that they would just

fly themselves to exhaustion.

But you’re right, we create

this synthetic female.

It is a chemical signal.

It’s a signal they detect with

their noses, which is really

their antenna on their head.

And they smell the signal, and

then they follow it to its source.

But as you can well imagine, after

doing that several times during a

single night, the male becomes fatigued.

And he does eventually become what we

in sensory physiology call habituation.

So he becomes habituated to the

signal, and so he no longer smells the

signal, not even the natural signal.

And at that point, he would become

sedentary and stop flying and

simply sit on the leaves or branches

of a tree and become inactive.

So he just gives up.

He simply gives up.

He will then probably

start the next night again.

The process will start again.

But, um, we also know that if the

female doesn’t mate within the first

48 to 72 hours of her emergence, her

ability to lay eggs actually decreases.

So, even if he eventually finds a

female, if it takes him two or three

days, and she’s been waiting two or

three days, She is going to lay far

fewer eggs than she would normally, and

so there’d be far fewer caterpillars.

So we get this dual pronged approach

of reducing mating and then actually

reducing egg laying in those that

might actually escape our system.

Okay, so while the guy pests

are flying around getting

confused, where are the females?

Like, have you managed to, I don’t

know, put them somewhere all by

themselves?

Yeah, well, we have done many

studies, um, to, we’ve released

insects and studied where they are.

We’ve gone into orchards

and collected insects.

So we, we have…

We understand where the female actually

resides when she is, when she is naturally

emitting her pheromone, something we

call, uh, the term calling behavior.

When she’s calling the male with her

pheromone, most insects, especially

codling moth, will climb to the tops

of the trees or fly to the tops of

the trees and sit there and wait.

But she won’t chase the male.

She sits and waits and she calls and

leaves her signal and she won’t go

in search of him if she doesn’t mate.

She just, she’s persistent.

Um, and so the males and

females don’t find each other.

It’s not like she goes in search of them.

Hmm.

Uh, just, what, what does

the pheromone lure look like?

Again, I have an image of, you know

how in public washrooms they have these

things that automatically exude a smell

so that it doesn’t smell bad in there.

Is that what it is?

Well, as you can well imagine,

entomologists are quite innovative,

and in this area, there’s one

different lure for every entomologist.

It’s kind of like everybody

wants to create a new mousetrap.

So, for example, the average lure,

That releases pheromone in a trap that

you might see hanging in an orchard

is, uh, usually just a little rubber,

piece of rubber, a little, what we

call a rubber septum, that they use to

close bottles off, and, and so it’s a

piece of rubber that you, you put the

pheromone in, but it could be a plastic

device that might be several inches long

and a hollow tube sealed at each end.

So, the lures can be all sorts of

types, much science has gone into.

developing these and finding, making

them inexpensive, making them robust,

making them protect the pheromone

because many of these pheromones

are sensitive to ultraviolet light

and so we have to protect them.

So there’s lots of different

lures and, uh, that you

might see.

Okay, so is each pheromone designed

for a different type of insect or

is there a general all encompassing

pheromone for all of them?

Yeah,

that’s the beauty of the pheromones.

That was our original, um, thinking.

And that’s why they work so well, is

they are very often species specific.

Okay, so for example, codling moth

uses a particular chemical for its

pheromone that we have since found.

There’s no other insect that

uses anything like that.

And it’s just a one.

What we call a one

component sex pheromone.

Now, that won’t, that pheromone will

not be detected or smelled or used by

any other insects or beneficial insects.

So it’s, it only affects codling moths.

Hmm.

But as the science of pheromones

evolved and as we learned more, we

learned that there were some insects,

let’s say, uh, like the oblique banded

leaf roller or oriental fruit moth.

Now they use something we call

multi component pheromones.

So they might have…

Two pheromones, two chemicals that

make up the complete pheromone signal.

And it turns out that some insects might

share in common one of those components,

but not both of the components.

So what makes it specific

is when two are together.

So we have learned that we can

control, in some cases, several insects

with one component of pheromone.

Well, how did the test

look out there in BC?

What kind of results have you got?

So what are the side effects?

If there are any,

I’m going to have to apologize, Susan.

My cell phone’s gone very quiet,

so I didn’t quite hear that

last question.

Um, my question is in where you

guys are in British Columbia.

So how is it all working?

And, uh, you know, how big a test

have you done of this particular

technique?

Uh, in the Okanagan Valley, we

have tested several thousand

acres of mating disruption.

Uh, at, at different times.

It, it has, um, these kinds of

technologies have led to the,

to the growth of the largest

organic apple industry in Canada.

Um, one of our valleys called the

Simokin Valley is, they, they call

themselves the organic capital of Canada.

So it’s, it’s been highly successful

for the, for the organic apple

growers.

Hmm.

And side effects?

Any negative side effects?

Well,

as you can well imagine, um, the negative

side effects, um, it’s hard to call them

negative, but they are, they have had

effects, is that when you stop spraying

conventional insecticides, which are very

broad spectrum, that protect your orchards

against all kinds of pests, we have seen a

growth over the last 25 years of invasive

species that, Um, are having an impact

on our organic systems and our pheromones

are not controlling those new pests.

So we have, we have made

ourselves vulnerable.

Uh, by not spraying to

these invasive incursions.

And, uh, they may have come

anyways, but, uh, the chemicals

would have kept them under control.

So now we’re having to deal with

a number of invasive species, um,

as, as a somewhat as a indirect

fact, effect of using pheromones.

Are you talking about species

like Japanese beetles that…

that are, you know, affecting fruit trees?

Well, certainly the Japanese

beetle is an invasive species.

Uh, but not a, not a pest of

apples in British Columbia.

Um, but we have a pest from

Europe called the apple clearwing

moth that’s become a pest.

Um, brown marmorated stink bug.

And in British Columbia, we

would consider apple maggot an

invasive species and a pest.

And we haven’t yet discovered

it here in the Okanagan.

Oh, really?

Wow.

Amazing.

Well, let’s hope you don’t get it.

We do certainly have it here.

Um, so that’s very interesting.

Now, are these, uh, pheromone

lures available to home growers

or community orchardists or

people who grow fewer trees?

You could, you could

certainly buy pheromones and you

can buy pheromone traps, but, um,

and so you could, there’s a number

of outlets in, in, uh, in Southern

Ontario or various parts of the U.

S.

that could.

There was just someone knocking on

my car door as I was talking to you.

Okay.

Um, so yes, you could buy these, uh, these

materials from a number of supply houses.

Um, now the traps, the pheromone traps

work very well for the backyard gardener

or the small, or who might have 20 trees.

But pheromones…

that we use for mating

disruption, unfortunately, work

best in very large acreages.

We, we tend to think of the minimum

acreage that mating disruption

might work to control calling mouth.

We might think that there’s

something around two to three

acres of apples is necessary for

mating disruption to be effective.

Okay, interesting.

Well, Dr.

Judd, in just a moment we’re going to

hear a few words from our sponsors,

but after that I want to talk to you

about your other project, I think your

newest project, and that is to breed

sterile pests to release in orchards.

Are you okay holding on

the line for a few minutes?

I am.

Great.

And to the listeners, please do send

in your questions or comments for Dr.

Judd.

Anything about fruit tree pests.

And past prevention, pheromones,

all that good stuff, and I’ll

ask those questions to Dr.

Judd for you.

Just send an email to us

now to Intu 1 0 1 gmail.com.

You’re listening to the Urban Forestry

Radio Show on Reality Radio 1 0 1.

I’m Susan Poisoner and we’ll

be back after the short break.

I’m Susan Poisoner and in today’s show

we’re pulling back the curtains on the

Sex Lives of Fruit Tree Insect Pest.

You’ll never look at an apple maggot

or codling moth again without blushing.

My guest today is Dr.

Gary Judd, an entomologist from

British Columbia’s Summerland

Research and Development Centre.

So Dr.

Judd, you’re still on the line, right?

Yes I am.

So we’ve been talking about the historic

approaches of using the knowledge of

insect pest mating habits as a way to

stop pests from ruining our fruit crops.

Now so far we’ve chatted about

pheromone traps, we’ve chatted about

other techniques, but I understand

that you’ve developed an approach that

involves breeding sterile insect pests

and then bringing them into orchards.

Can you tell me a little bit about that?

Yes, I certainly can.

Now, I want to be very honest.

This technique was developed by an

entomologist who has since retired from

the Summerland Research Centre, Dr.

Jinx Proverbs.

And, um, he worked, his career spanned

somewhere between 1950 to 1985.

So it’s a fairly old technique.

But he was working on codling

moth, which was the key pest

of apples here in the Okanagan.

And the understanding and belief

was, if you could remove codling

moth from the orchard, then you

really could grow organically.

And that’s pretty much the case today.

So he, he was studying, um, a technique

called sterile insect technique.

And in that technique, what you do is

you sterilize the male moths with, um,

could be x rays or chemical sterilant.

And those sterile moths are

then bred up in the laboratory

and released into orchards.

Those sterile males then mate

with the wild female codling moth.

And, as it turns out, in codling

moth, the female only mates once in

her life, and if, if she mates with

a sterile male, she’s fully satisfied

and will then begin to lay eggs, and

those eggs will not hatch, they will

be in fact sterile, and you won’t get

any, uh, caterpillars forming, and you

won’t get any damage in your fruit.

Hm,

quite amazing.

I’m just trying to imagine what

this would look like, like, where

do you get all these male insects,

what happens if there’s like, Female

insects in the bunch and you put them

in an x ray machine or something.

It’s just

yes.

Yes.

Well, dr Dr.

Proverbs developed a technique for

for raising these these insects in

trays of diet and Those the rearing

system he designed is housed in a in

a Several thousand foot, uh, Griffith

facility in the Soyuz, British Columbia.

That’s right on the border

to the United States and the

southern end of the Okanagan.

So that, that was a several

million dollar facility.

That really is, um, it, it,

it produces millions of moths

per week in a closed facility.

And, it produces, as it turns out, it

produces males and females on that diet.

But, the males and females are both,

uh, irrate, what we call, they’re,

they’re, they’re exposed to, to, uh,

irradiation, a gamma radiation, very

similar to x rays, in a machine.

And so, both the males and

females are sterilized.

So, in fact, When what you

release into the orchard are

sterile males and sterile females.

The sterile females just lay sterile

eggs and the sterile males go in

search of, of the wild females, and

that causes them to lay sterile eggs.

So this, so

that’s how the technique works.

So this is amazing.

So this has been, been in

existence for many years.

Is it only now being brought

into, uh, orchards or, or

No, as I say, Dr.

Proverbs career spanned the 1950s to the

mid 1980s and then another entomologist

took over his program on his retirement.

And it took, um, from 1985 to

about 1992 to get the program that

we have fully functioning here

in British Columbia in operation.

It was a joint venture of regional

governments, provincial governments, and

federal governments to build the facility.

And in 1994 they made the first

releases of sterile codling moths.

And ever since 1994, um, they have

been controlling codling moth in

the Okanagan Valley, uh, uh, with

the sterile insect technique.

So ever since the beginning of my career

when I was working on pheromones, the

two programs were running parallel.

Hmm.

So do you need both programs now

or, or is one being phased out?

Well,

um, the sterile insect program

is, it’s a good question.

Um, it’s a very expensive program.

Um, and…

We, um, it is very specific to codling

moth, and it’s the only pest that we can

currently control here in BC with it.

Now, we have a number of other indirect

pests, as I said to you earlier, we

get a number of, uh, secondary pests.

And so my work, uh, for the last

30 years has been in controlling

those other pests with pheromones.

Now, we know full well we can also

control codling moth with pheromones.

And so we can quote and quote codding

moth and several other insects

if we just use pheromones, but

it’s a very long running program.

It’s very successful

and it’s done area wide.

Everybody, everybody

must participate in it.

It’s legislated.

And so you can well understand

that even if we had an alternative

technology like pheromones.

Um, it’s a very difficult, uh,

step to take to, to reverse that

program that’s been so successful

for our control of codling moth.

Wow, so basically it looks like

the two are working hand in hand.

You’ve got the sterile, uh, insect program

for codling moth, and then you’ve got the

pheromones working for the other insects.

That’s correct.

Do you need to spray anymore?

Are these spray free orchards?

Well,

most of our growers rarely

spray except, as I said, for

these, these invasive species.

We, we, um, not all, not all

growers make use of the pheromones.

So those that don’t use pheromones,

um, the pheromones are primarily

used by organic growers.

We still have conventional growers

who would have to spray for

some of these secondary pests.

And more recently, since 2006, we’ve had

this invasive pest, the apple clearing

moth, that is causing us some concern

because our organic growers are now

having to spray to control that insect.

And, unfortunately, we have a

pheromone for it, we have identified

the pheromone, and we’ve tried mating

disruption, but we are dealing with

a pest that’s in very large numbers.

Uh, and we, we need to get populations

down under, uh, lower levels before

pheromones are really going to be

effective.

Mm hmm.

Well, so what, what does

the future look like?

What is your goal for the future?

Well,

the, the goal is to, uh, minimize

pesticides wherever we can, to

use, um, the, this information

on chemical ecology and mating

systems to control as many insects.

The most exciting part of my work

right now is that we have only just

in the last two years discovered a

group of chemicals, natural chemicals,

that attract the female insects.

Many female insects.

And so we do think if we can trap enough

female insects, And hopefully I’m not

being naive like my predecessors, but

we believe if we can trap the female

insects, then we could, uh, control

those populations without pesticides.

So, my work and that of others will

continue on into the future after

I’m retired, but, uh, this whole

area of chemical ecology and using

natural chemicals, I think is, is,

uh, going to be around for some time

and, and only get more interesting.

That is interesting.

Is it happening anywhere else,

or is this just a BC program?

Am I going to see it here in Ontario?

We’ve got listeners in all

over the United States.

The sterile insect program

for codling moth in British

Columbia is a unique program.

It’s the only one of

its kind in the world.

We, we have other sterile insect

programs in the world, but mainly

in the tropics and they’re used

to control tropical fruit flies.

There’s one in Arizona that controls

a pest of cotton pink molar, but the

codling moth program in BC is unique.

It is, um, being tested.

The technique is being tested,

uh, by people in South Africa, in

South America, and in New Zealand.

And the way it’s being tested is they are

buying moths from our facility to release

and, uh, during their season, because

being Southern Hemisphere countries,

they grow in the opposite season to us.

So when our facility is, uh, down

in the, in the winter, we can

produce moths and sell them south.

Uh, and, and there are, so there are

other countries and industries trying

to use this technique for cotton.

Hmm.

I’m very curious to see how it develops,

because I know that there are a lot

of people out there that would love

to know that the apples and, and

pears and all the fruit that they’re

buying doesn’t have toxic chemicals

on it, so it’s a hopeful development.

It very much is, but um, I will say

that there’s a very large industry

outside of British Columbia, the

Washington State industry for example.

Almost 80% of its industry uses mating

disruption to control condom moths.

There are other industries that are

very progressive in southern Ontario.

I know you have a group of pests

that have not, um, have not been able

to be controlled with pheromones.

Something like apple maggot.

And that does pose a problem

to entomologists and growers.

And so we’re having to develop

different techniques to control pests

like that.

Hm, quite amazing.

Well, Dr.

Judd, it’s been really

great to talk to you.

And I appreciate you

coming on the show today.

Well, thank you so much for having me.

I was glad to be

here.

Oh, great.

Okay, goodbye for now.

Hopefully we’ll talk again someday.

Goodbye, Susan.

Thanks.

Well, if you missed the beginning

of this interview, or if you would

like to listen to it again, you

can of course download the podcast.

Just go to orchardpeople.

com slash network.

And while you’re there, you can sign

up for our iTunes podcast feed so that

you can catch up on previous episodes

and so that you don’t miss future ones.

But wait!

Don’t go anywhere yet, because coming

up after a word from our sponsors, we

will explore fruit tree irrigation.

Is it, is there a right way?

Is there a wrong way?

Is this a hard thing to do?

Apparently it is.

And we’re going to find out

more from Sacramento based

fruit tree expert Chuck Ingalls.

You’re listening to the Urban Forestry

Radio Show on Reality Radio 101.

I’m Susan Poizner, and we’ll

be back after this short break.

I’m Susan Poizner, and you’re listening to

the Urban Forestry Radio Show, a program

where we learn about fruit trees, food

forests, permaculture, and lots more.

Thanks for tuning in.

In the first half of the

show, we spoke to Dr.

Gary Judd about understanding the

sex lives of insect pests, and

how that can help us protect our

trees from insect infestations.

Now we love it when you reach out and

contact us and we’ve got an email here

from Chase who says, Wow, what a show.

Very interesting.

Good luck with the continued research.

So I wish that Dr.

Judd was still on the line so we

can hear that encouraging comment.

Now protecting your fruit trees

from insect infestation is really

important but one of the key ways that

you can do this is to actually just

care for your trees properly in the

first place, especially when they’re

young and establishing themselves.

Now, there are various tasks involved

in fruit tree care, including annual

pruning, fertility management,

and more, but one of the key jobs

is correct fruit tree irrigation.

Now why is that so important?

Well, fruit trees can only take in

nutrients from the soil in liquid form.

So, a dehydrated fruit tree is

actually a malnourished fruit tree.

And when a fruit tree is

malnourished, it is weaker.

And of course, more vulnerable

to pests and disease.

So, I wanted to talk to Chuck Ingles.

An expert in palmology, viticulture,

environmental horticulture, and

more from the UC Cooperative

Extension in Sacramento, California.

We’re going to be talking in a minute.

Now if you have questions and

anything related to fruit tree

irrigation, do send your email

to us now in studio 101 at gmail.

com.

Now I understand that

Chuck is on the line.

So Chuck, are you there with me?

Yes.

Hi, good to be here.

Good to have you.

How’s the how’s the weather over

there in California this year?

Is it as dry as it has been in years past?

The summers are definitely typically dry,

and right now we’re going through a heat

wave, as I think much of the country is.

We’re supposed to reach about 104, 105

today.

Oh my goodness.

Oh, that doesn’t sound very pleasant.

And all week.

Oh my goodness, I’ve been complaining

here in Toronto, it’s hot too.

So, if irrigation is important

anywhere, it must be in California,

where your heat is just…

so extreme.

Um, well, tell me a little

bit first about California.

Why is proper irrigation essential

in in your part of the world?

Well, fruit trees won’t grow in a

desert without water and we basically

are in a desert in the Central Valley.

Uh, and so Irrigation

is mandatory every year.

In some parts of the country,

it’s not, but here we definitely

have to water and water a correct

amount to keep the trees healthy.

Well, it’s interesting because I

know here in Ontario, there are some

orchards, organic orchards, that

don’t even have irrigation systems.

Yeah, and that can work where you don’t

have really hot conditions and maybe get

some summer rainfall, which we don’t.

And the roots are.

Deeper because they have to grow deeper

because that’s where the moisture is.

So that builds their drought tolerance.

Yeah,

and yet it can also lead to trouble.

This year we had such a dry spring.

We have a we’re having a very dry summer.

I don’t know what what would

that do to those fruit trees.

These are beautiful orchards

that haven’t had, you know,

hardly a drop of water in months.

Well, we

get that problem when we don’t

have enough winter rainfall.

And so often, not often, but sometimes

when that happens, growers and

individuals need to water their trees

late in the winter to start the soil,

to start the season out with a full

profile of moisture in the soil.

Uh, so when you don’t start the season,

Enough, then you’re going to with enough

moisture, then you’re going to go through

the summer with stress of some kind.

And in your case, it may not

kill the trees, but the trees.

will probably be stunted, and

they’ll have smaller fruit.

Hmm.

Yeah, who knows if they

even have fruit at all.

I looked at our trees in our orchard

park, and we spend hours out there on

the weekends just with hoses watering

and watering because it’s been such a

dry year, and I just think, you know,

whatever fruit is on those trees, if

I was the fruit tree, I would drop it.

Because that fruit, you know,

it takes up a lot of energy.

So, um, yeah.

So, I mean, is that the case?

Does it drop the fruit

as well when it’s dry?

Yeah.

If there’s not enough fruit, uh,

enough moisture in the soil, then they

may not set as well to start with.

But yes, if they’re, if they go through

the season with insufficient water,

then they will drop some of that fruit,

no doubt.

So, so whether it’s in

California, what do the irrigation

systems look like in orchards?

What, what kind of

irrigation do you guys do?

Well, uh, originally there used to be

a lot of flooding, and there still is

some, uh, there was furrow irrigation,

and more and more, uh, orchards are,

then became sprinkler irrigated,

and now drip irrigation and micro

sprinklers are probably at least as

prominent as sprinkler irrigation.

What are

the, what, mm hmm,

sorry.

Drip lines, uh, you know, a single

drip line going down the center,

or usually one on either side.

If there’s micro sprinklers, there’d

be a single line with, you know,

a micro sprinkler between each

tree.

What are the pros and cons

of the different approaches?

Um, the pros of using drip and

micro sprinkler is that it uses less

water, especially drip irrigation,

as long as it’s managed correctly.

Uh, the con for drip irrigation is that…

You don’t wet the entire soil

surface, and that’s true with

micro sprinklers, too, usually, but

you wet a bigger area with micro

sprinklers than with drip irrigation.

But you can still do it.

For instance, all of our grape growers

here use, those that use drip irrigation,

it’s right down the row, so the middles

between the vines are not getting

any water, which you can still do it.

Uh, it’s just…

Um, for fruit trees, we’d like to have

a little wider coverage because the

trees are bigger.

Yeah, I’m just kind of imagining how in

the ground as the roots are spread out,

they, they kind of probably congregate

those underground roots towards

where that drip system is, and then

everywhere else, either the roots are

dead or they’re just not very active.

Is that what I might see if I

could go and look into the soil?

That’s exactly right.

Uh, if you start the spring with

a full profile of soil, Uh, uh,

I’m sorry, water in the soil.

Then the roots can continue to grow

out into that below the, you know,

well below the surface through the

season, cuz there’ll be some moisture.

As long as there’s not a lot of weeds,

which take a lot of that soil moisture

away, then they can continue to grow.

But they will dry out eventually

and more and more of the water will

be taken up from where the soil is

moist, uh, from drip irrigation.

Hmm.

Interesting.

So thinking in terms of home growers,

people in their backyard, uh, so you

say micro sprinklers, I mean, I know

people who put a regular, you know,

grass sprinkler or whatever on their

tree and they just leave it for a few

hours and water their tree that way.

Is that a good way to water your tree or

if you’re doing a backyard orchardist?

It

certainly can

work as long as you, uh, water more when

it’s warm and water less when it’s cooler.

Uh, but nowadays, especially

in California with the drought,

we’ve had a four year drought.

And some people say we’re not

in a drought, but we still are

and we almost always will be.

Uh, we’re going to need to

pay really close attention to

how much water we’re using.

In many water districts in urban

areas, people were given last year

one or two days a week to water, which

really isn’t enough for some things,

including lawns and fruit trees,

too, if you have drip irrigation.

Uh, so, um, uh, I forgot where I was

leading with that, but, uh, but it

is important, really important to

water, uh, Enough and not water too

much.

Yeah, that’s the other problem.

That’s the other problem that you get.

You know, um, we have, uh, little

espalier, lovely little espalier fruit

trees in our backyard and there’s the

temptation to water them every day

because, you know, we have the water.

Why not?

It’s good for them, right?

But could that be a problem as well?

Right.

Watering every day could work if

you’re under really, uh, severe

heat and you have drip irrigation.

You may need to water every day

because you have few points, sources

where that water is available for

the trees and it dries out quickly.

Uh, but generally, sprinkling, uh,

and watering every day otherwise.

Is not a good idea because you

want to let the roots go deeper.

You want to let the soil not dry

out, but become less saturated.

So the air comes back into the soil

because when you water, especially flutter

for irrigation or sprinklers, you drive

a lot of that moisture out of the soil,

especially under clay soil conditions.

So you need to let it dry out a little.

And the other thing is there are diseases

that Occur when the soil is wet all

the time, especially in clay soil.

So, you want to not have the soil.

Wet all the time or anaerobic.

Oh, well, that’s an interesting point.

So if you water too much you can be

incurring Inadvertently encouraging

disease so we wouldn’t want to do that

and we definitely have clay heavy clay

soil Here in in Toronto at least so I have

two questions here that just came in from

Clifford now He says his first question.

What is the best type of

emitter to use for fruit trees?

And where can I get them?

Now let’s see, he has another question,

so take note of question number one.

Does chlorination affect fruit trees?

Um, we use city water at

home from Clifford, so what,

what do you have to say?

Okay, first on the drip emitters, uh,

my preference, and I think a really

good strategy, is to use Inline

drip tubing, which has the drip

emitters built into the drip tubing.

Uh, that way you just run it,

uh, in a circle around the tree

or in rows alongside the tree.

Uh, and you don’t have to worry

about an emitter getting, uh,

kicked off when you walk around.

Uh, so it’s, it’s just a, it

looks like drip tubing, but it

has the emitters built into it.

And

where would you be able to

get something like that?

Yeah.

Uh, big box stores, Terriot, um,

and, uh, irrigation supply stores.

You have a better line of them

usually, and they’ll help.

They usually work with commercial,

um, landscape people, but

they’ll work with homeowners too.

Uh, so there are definitely

places to buy it.

Hardware stores too will often have it.

Uh, the problem is, and we often

recommend using wood chip mulch.

So you never see the drip tubing, which

can be a problem because you never

know if it’s clogged and not working.

That’s why micro sprinklers are

often good, uh, because You can

turn it on and look down the row and

see, oh yeah, they’re all working.

Uh, unlike drip irrigation, you

can’t see if they’re working

at all.

And what about that

question about chlorination?

We are indeed using city water to water

these trees and, uh, I can sometimes

even smell the chlorine in our tap water.

How does that affect the

fruit trees?

Yeah, chlorination is fine.

It doesn’t hurt anything.

Oh, good.

Yeah, no problem at all.

It’s only when you try to use something

that’s like, uh, Bt or some other

organism that you’re spraying for

pest control, there’s some of them

that you need to have non chlorinated

water because it kills the organism.

Uh huh.

Spraying

on the tree.

That would not be helpful then.

No.

You’re trying to put something

good on and it’s dead by the

time it gets on your tree.

Exactly.

Well, okay, so we’ve talked about

emitters and a little bit about frequency.

There would be, it would be so

good to know how much is enough.

Like is there a way to test,

is my fruit tree getting

enough water or too much water?

Well there certainly…

It are several ways.

Uh, one way is to dig in the

soil and see how deep the water,

the moisture in the soil is.

And that’s a really good strategy, but

there’s better ways than digging a hole.

And one includes using a soil sampling

tube to pull a core of soil out of the,

you know, out, and you can look at it

and see how dry it is on the top versus.

How deep do you want it to be watering?

Like, do you want it to, the soil to

be damp 2 inches down, 6 inches down?

Well,

the majority of the fruit tree roots of

almost all fruit trees in most conditions

are down to about 18 inches to 2 feet.

The majority of…

Tree roots are in the top two feet

on large trees in the top three feet.

So you may have a taproot initially when

you plant the tree, but that taproot.

Basically goes away and the roots

move out laterally, so all your roots

are moving out and even beyond the

drip line or the edge of the canopy.

They’re going outward.

So you want to water that deep.

So you want to somehow check

the soil that deep if possible.

Hmm.

And if it’s…

But there’s other ways.

Okay, yeah.

Yeah, there’s other ways you can,

you can, um, you can keep track

of evapotranspiration, which

is a mouthful, I understand.

Evapotranspiration is a combination

of evaporation of water from the

soil and transpiration of water

through the leaves of a tree.

So, there are…

Sites and I looked on online to

see if Toronto has sites that list

the daily evapotranspiration rates.

Uh, but I couldn’t find any.

I don’t know if you have them

available, But basically the warmer

it is, the more water you’re applying.

The cooler it is, the less

water you’re applying.

Hmm.

Somebody’s got to figure

out an easy way to do this.

I’ve got at home, uh, a

little self watering pot.

And, uh, it’s for little seedlings

that I’m growing for the garden.

And you can see a red line on

this sort of, it, it looks like a

thermometer in the, in the soil.

And it tells you, okay, uh,

you need to add more water.

Somebody needs to invent that for

homegrowers because, you know, and

also it’s like the soil is moist today.

So do you want to wait until it’s

dry, dry, dry until you water again?

I don’t know.

Your thoughts on my meandering thoughts?

Well, there are soil moisture

testers, but they usually

don’t go very deep in the soil.

And…

And, and there are various sensors.

I use certain types of sensors

that are a little complicated,

but not that complicated.

They go deep into the soil.

So you can basically have eyes

in the soil and see how dry the

soil is without having to dig.

But those are a little complicated.

And, and, uh, the other thing

is, if your trees are healthy.

And they’re growing well, they set a lot

of fruit and produce a lot of good fruit.

You’re probably doing something right.

Uh, but if you, a lot of times you’ll

have small fruit or you’ll have, which

could be related to several things,

or you’ll have stunted trees, which

could also be related to other things.

Uh, but, uh, but tree

health and production.

are a good indication that

you might be doing something

right.

Hmm, well that’s a good

way to think about it.

I so appreciate you coming on the show.

I feel like we could continue

talking for quite a while, and it’s

amazing, because again, you think,

irrigation, oh isn’t it basic?

And it’s kind of complicated.

If I could just say one other thing, this

is really common where people think you

need to set the hose right by the trunk.

That’s where all the roots are.

You don’t want to water by the trunk.

Unless it’s a really young tree,

the roots are moving outward.

You’ve got to move that water

out and keep the trunk dry

below ground.

That’s a really good point because,

of course, uh, you know, they say you

really want the, under the canopy of

the tree, the farthest canopy, so it’s

actually quite far from the trunk.

Right, exactly.

Roots are near the trunk too, but

we want to keep the trunk dry to

keep, uh, to keep it from dying.

Some diseases love that moisture around

the trunk, so keep that area dry.

I have another, Clifford

has sent us another email.

He’s obviously very

interested in this topic.

Now he says, and this is interesting

actually, Is it, is it best to water

a fruit tree once during the day?

Or multiple times during

the day, morning or evening?

Well, the multiple times would

only be if there was a slope and

you don’t want it to run off.

So you water a little, let it

sit, water a little, let it sit.

Uh, generally water all at once to

get it down to the 18 inches, of

course, unless you have the slope.

But regarding his other question

about emitters, if he’s gonna use

punch in emitters on the drip tubing,

then use pressure compensating Emitt.

Generally, one gallon per

hour or thereabouts is

best.

Wow.

Fantastic.

Oh, thank you so much for

coming on the show today.

Oh, you’re welcome.

My pleasure.

Hopefully, you’ll come back

and I know you, there’s lots of

things that you can talk about.

So maybe we’ll get you back another day.

We’ll talk about something else.

Yep.

Okay.

Okay.

Thank you so much.

Goodbye.

Bye.

Okay, well, that was fast.

That’s all for the show today.

And it was really nice to speak to

my special guests, Chuck Ingalls,

Palmology, Viticulture, Environmental

Horticulture, and Master Gardener

Advisor at the University of

California Cooperative Extension.

And earlier in the show, I spoke to Dr.

Gary Judd, an entomologist from

British Columbia’s Summerland

Research and Development Center.

So if you missed part of the

show and you want to listen

again, just go to orchardpeople.

com slash network where you can access

this episode and all the other episodes

that we’ve done about fruit trees,

food forests, and permaculture gardens.

And while you’re on the site,

do sign up for my monthly

newsletter at orchardpeople.

com.

And I’ll remind you about

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Tune in to the show again next month,

and we will have more great guests.

You’re listening to the

Urban Forestry Radio Show.

I’m Susan Poizner from the fruit tree

care training website, OrchardPeople.

com, and I look forward

to seeing you next month.

If you want to learn more about

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Thanks for tuning in and

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Thank you for listening

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Susan Poizner, right here

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