Peach Leaf Curl report from NWFruit

[cdamarjian]

In the current NW Fruit newsletter, Sam Benowitz, founder of Raintree, evaluates 13 peach trees planted at the Mt. Vernon Research Station and describes treatment for severe defoliation.

Peach Leaf Curl
Report from Sam Benowitz
Peach leaf curl is a disease caused by the fungus
Taphrina deformans. Peach leaf curl affects the
blossoms, fruit, leaves, and shoots.

On May 23, after a very wet winter and spring,
we evaluated the peach trees in the Fruit Garden
for leaf curl and also fruit set. This has been a
horrible year for peach leaf curl. Even the varieties
marketed as leaf curl resistant, which typically
have some slight curl that we can live with, this
year are badly defoliated.

In an attempt to save the trees we are removing
all the fruit, thinning out damaged branches,
and then cutting back the remaining branches
severely. Our hope is that each tree will send out
new leaves once it doesn’t have to support fruit
production and so many branches. We will see
over the summer how that works.

While most of the peach trees at our Garden
were decimated, the Frost and Betty peach trees have only
moderate peach leaf curl, and have very good fruit set. The
Landt variety had no leaf curl but nevertheless had no fruit.
At the Fruit Garden, our peach trees are in proximity to each
other along the south fence, some 10 or 12 feet apart. Only
one, the All Star was about 50 yards away which may have
contributed to its lack of curl. The newly planted genetic
dwarf nectarines rated 4 on leaf curl.

.In previous years our garden trees have been sprayed with
lime sulfer, applied in late December through February at
about three week intervals. Ziram is also an effective spray.

Variety / Damage / Fruit Set
All Star 2 Heavy
Autumn Rose 5 Light
Avalon Pride 4 None
Betty 2 Heavy
BlackBoy 4 None
Charlotte 2 Light
Frost 2 Heavy
Indian Free 4 None
Landt 1 None
Mary Jane 4 Light
Naniamo 5 Light
Salish Summer 4 None
Township 5 Heavy

Damage Rating:
1 slight, 5 all branches

[Cuckoo4cocopuffs]

My Charlotte, Indian free and Salish summer only had.a handful of PLC leaves this year in Portland. I sprayed them with “Italian dressing” (olive oil, grocery store vinegar, dawn dish soap and water) in late winter this year once just as the buds were swelling and starting to scale out. Took a few minutes each.

[DennisD]

@cdamarjian

In an attempt to save the trees we are removing
all the fruit, thinning out damaged branches,
and then cutting back the remaining branches
severely.

If I followed this procedure this year on my young dwarf Frost tree, there would be nothing left to do photosynthesis. The fruit already aborted. I suppose I could sever it above the root stock and do summer grafting with a better quality plum which are not such a headache
Dennis
Kent wa

[Bradybb]

@cdamarjian

In previous years our garden trees have been sprayed with
lime sulfer

I wonder why they stopped.

[cdamarjian]

I wondered that too.Their row of “curl-resistant” trees is about 12 years old. Perhaps they were testing the premise that, with maturity, the trees would develop resistance.
My 15 year old Salish Summer no longer gets curl, but the many blind branches suggest its time is about up… a gardener’s race against the clock.
In October, when NW Fruit has their fall fruit day, I’ll ask about their plan for peaches.

[JohnS]

I have a peach tree. I didn’t buy it. My wife cans peaches and we threw the pits in the compost. It got hit furiously by PLC last year and this year. I spray compost tea on my trees in the spring. They recovered over a course of a few weeks. They look great now. I got about 7 fruit last year and it looks like I’ll get a couple more this year.

JohN S
PDX OR

[Oregon_Fruit_Grow]

good find Chris. IMO, there is not much to infer from one off observations on resistant varieties. I have few of the listed varieties growing in my yard or FIL yard.

3 yr old Frost, 1 yr old Salish Summer both showed handful of leaves with curl. Betty, Frost on M2326, Indian free all planted this spring showed same amount of curl few leaves. It didn’t really impact their growth and all are growing vigorously.

Oregon Curl Free planted next to Frost didn’t have any curl - but looks like the tree has canker that has slowed the growth and will probably be removed next year.

Meanwhile, I have dwarf honey-babe, pix-zee, nectazee, Fantasia nectarine, all planted this year about the same time with new trees that showed curl. None showed any curl.

Wooden leaf farm have observed that there are times when they go curl free for 4 years without spray and get hit on year 5. One crucial point from their observation is if the tree minimal curl one year its expected to get worse the next year. It’s all about inoculant load that was generated and survived the winter.

[cdamarjian]

I stopped by the NW Fruit orchard in Mt Vernon, Washington to check out the severity of the PLC damage and the extent of the remediation.

Nanaimo had had its leaves nearly all removed

while Oregon curl free retained about half its leaves and fruit.

Even some of the new leaf growth on Indian Free and Avalon Pride appeared curled.


I sense that those of you south of Seattle probably never experience damage like this.

I used to think that my planting in a forest pocket was the cause of my battle with PLC. However, these NW Garden trees are planted out in the open with great air flow and full sun.

I’m curious to keep track of these trees…Will leaves harden off in time? Is the plan to resume spraying next year? Will this year’s stripped trees fruit next year?
Quite an interesting experiment that we don’t have to sigh over in our own backyards!

[swincher]

@cdamarjian

Even some of the new leaf growth on Indian Free and Avalon Pride appeared curled

I noticed that with my Oregon Curlfree, too, even though most of the new growth looks clean, some is still coming out like this:

[cdamarjian]

@swincher
Same here on Oregon Curl Free and Nanaimo

…even with fall and spring sprays of Ziram. A sunny bud-break in Jan, followed by constant rain in Feb and March, was the problem - not to say that isn’t our normal weather pattern.

I think you’re doing really well for no spray. From the 2 fruit I tasted last year, I thought that the flavor was quite good - better than a bland Frost. Don’t graft it over quite yet!

[murky]

I’ve got minimal curl this spring.

Here is my Frost. The mature unknown, maybe RedHaven, is also doing well with respect to peach leaf curl.

[Oregon_Fruit_Grow]

@cdamarjian

I sense that those of you south of Seattle probably never experience damage like this.

This is what I think too, given Jafar’s tree hasn’t got much curl south of Vancouver, WA disease intensity if much less.

@cdamarjian

I’m curious to keep track of these trees…Will leaves harden off in time? Is the plan to resume spraying next year? Will this year’s stripped trees fruit next year?

My guess is that they stopped spraying older trees with an assumption that they don’t need it after the juvenile stage. In my guess, these trees will survive to see next year and continue growing if they were sprayed.

@cdamarjian

…even with fall and spring sprays of Ziram. A sunny bud-break in Jan, followed by constant rain in Feb and March, was the problem - not to say that isn’t our normal weather pattern.

Have you tried to find what the orchards near your place spray and at what rate/dosage. I thought ziram was nuclear option wonder if the strain has mutated to gain resistance to Ziram.

[cdamarjian]

For years I sprayed monthly from Nov to March with lime-sulfur alternated with Kocide. Still got 25% curl. It must be my location …since so many others get less than 25% curl with no spray.

I went over to the dark side (‘nuclear option’) 2 years ago, hoping for just fall and/or spring sprays. The first year no PLC…I was thrilled…but the weather conditions were not as favorable to PLC. This past year got about 15% curl. Hard to judge Ziram’s effectiveness on these 2 disparate years.

Next year I’ll try limesulfur or Kocide Nov-Feb and Ziram in March.

NWFruit is the closest orchard to me. I’ll be checking on their plan for the fall and spring. I’m pretty sure they’ll be back to spraying next year.

[murky]

I’ve had moderate damage some years, never severe that I recall. This year was good.

[Vincent_8B]

Hi Jafar.
Remember I bought Veteran peach last year from Costco. This year it has some leaves curl and sets about dozen of fruits now.

[cdamarjian]

NW Fruit in Mt Vernon held an open house today so I stoped by to see if I could find out more about the severe PLC infection in the peach planting. I ran into Sam Benowitz , founder of Raintree, who explained that, in the fall, the peach trees had been sprayed with oil/sulfur at leaf drop, but that sprays in Jan and Feb - a second and third oil/sulfur plus Ziram at bud break- had been mistakenly omitted. So, as it turns out, not spraying the trees was an accident. He said the sprays would resume next year.

He joked that, for our northern region of the PNW, the label “PLC-resistant” was more of a marketing technique than an actual fact.

He also shared that he thought Oregon CurlFree and Frost were identical. Sam said that the developer of Oregon Curl-Free had confided in him that, rather than go through a rigamarole with Frost, he had renamed the tree. (I know there are many facts missing in this story! )

In the name of nerdy science, it would be interesting for anyone growing both Frost and Oregon CurlFree to do a comparison of flowering, ripening dates, and taste.

[Oregon_Fruit_Grow]

@cdamarjian

He joked that, for our northern region of the PNW, the label “PLC-resistant” was more of a marketing technique than an actual fact.

I am in serious agreement with his joke. My conclusion for home orchards is all dependent on how much fungus hitch-hikes from the nursery and how aggressively it’s managed for the initial few years.

@cdamarjian

He also shared that he thought Oregon CurlFree and Frost were identical. Sam said that the developer of Oregon Curl-Free had confided in him that, rather than go through a rigamarole with Frost, he had renamed the tree. (I know there are many facts missing in this story! )

Another well known nursery owner told me the samething Frost and Oregon Curl Free are the same, apparently OCF was invented to bypass Frost trademark. I also think Frost is same as California Curl free variety documented in USDA list but unavailable for purchase anymore.

@cdamarjian

In the name of nerdy science, it would be interesting for anyone growing both Frost and Oregon CurlFree to do a comparison of flowering, ripening dates, and taste.

I have Frost and OCF next to each other, they bloomed a handful of flowers at the same time this year. Although it looks OCF has canker hopefully it will live to bloom next year and set fruits.

[murky]

@cdamarjian

Sam said that the developer of Oregon Curl-Free had confided in him that, rather than go through a rigamarole with Frost, he had renamed the tree

What rigamarole? I don’t understand what is being said here.

[cdamarjian]

As @Oregon_Fruit_Grow corroborated, it may have been something about the Frost trademark. Sam did not elaborate.

[Bradybb]

Thanks,that explains some things.
Is Sam working at the Mount Vernon station.He did have connections with them,when running Raintree.
During those Day of Classes that Raintree had,one of the guys sharing,was Gary Moulton,(spelled something like that),who was the director.