Re: [apple-crop-2] Apple leaf disorder

[David Kollas]

Dan, Brian, Kari, Mo, and others:

Having read your comments and links, I looked more closely at my 
symptoms.  I was wrong about its association with yellow delicious breeding.  I 
can find it in Macoun, Empire, and many others.  The symptom common to all that 
I looked at with magnifying
glass was scattered dark blackish raised dots in the live or dead “spot” that 
often retains its green color after surrounding areas have
yellowed. I did not find any affected leaves that exhibited the concentric 
bands noted in the 2012 blog, with click-enlarging photograph, by Dave 
Rosenberger on Glomerella leaf spot.  Therefore I conclude it is not Glomerella 
infection.  If it is Marssonina leaf spot, I would
not expect it to have survived all the captan sprays I have administered. Sooty 
Blotch and Flyspeck, in spite of all the favorable
conditions for those diseases, are rare here at this time.  I suppose it could 
have a physiological cause that made areas of the leaves
susceptible to opportunist fungi, and some petri dish work in a lab might 
isolate and identify those raised black dots. It is discouraging
to loose the leaves before harvest, not knowing why, nor what could have been 
done to avoid it,
 
David Kollas


> 

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Re: [apple-crop-2] Apple leaf disorder

[Daniel Cooley]

When this is on a Golden Delicious at this time of year after a summer like 
this, it’s likely that it’s necrotic leaf blotch. No pathogen has been 
associated with it, so we blame it on bad horticulture and call it a 
“physiological disorder”. It’s interesting that zinc and ziram applied in the 
summer will reduce the problem. 

https://articles.extension.org/pages/60614/golden-delicious-necrotic-leaf-blotch-in-apple-trees

This is one of a few problems that were relatively common in the Southeast and 
Mid-Atlantic, but that we didn’t see in New England until recently. We’ve also 
seen more black rot, bitter rot, and Marssonina leaf blotch. These are all 
fungal diseases, and I think they and NLB are all related to warmer night 
temperatures. I also think that we have seen the build-up of inoculum for the 
fungal problems over the past few seasons, and that it will more important to 
sanitation, copper and summer fungicides to keep them from building up to more 
significant levels. 

Marssonina leaf spot has been a growing problem, and it could be that. We 
identified last year and this year in a few orchards, and it has been found in 
eastern NY. Here’s an article from Srdjan Asimovic at the Hudson Valley Lab.

https://blogs.cornell.edu/acimoviclab/2018/09/24/marssonina-leaf-blotch-causes-apple-leaf-defoliation-where-cover-sprays-were-stretched-in-summer-2018/

We’ve had a lot of bitter rot and black rot on fruit. Theser are Glomerella 
leaf spot and frogeye leafspot, respectively, on leaves. 

From Dave Rosenberger a few years ago, GLS: 
https://blogs.cornell.edu/fruit/2012/08/31/glomerella-leaf-spot-a-new-disease-affecting-golden-delicious-apples-in-ny/

If you want to nail it down, you need to submit samples to a pathology lab.

Dan


> On Oct 9, 2018, at 12:35 PM, maurice tougas  
> wrote:
> 
> Yup seeing same here. No captan or phosphorous . Goldens but I don't recall 
> seeing on Jonagold. Ill check.
> 
> Mo Tougas
> 
> On Tue, Oct 9, 2018 at 12:26 PM David Kollas  > wrote:
>   The photo below, taken yesterday in my orchard, shows a Jonagold tree 
> among other Jonagold trees that
> are dropping leaves.  Severity varies from few to many leaves showing the 
> spots and leaf-drop on different trees.
> Similar, but less severe symptoms appear in other varieties that have yellow 
> delicious in their heritage.  I suspect 
> it to be a fungal infection, because the spots appear on green leaves, which 
> then turn yellow and drop.  Frequent 
> captan plus phosphorous acid sprays have been applied for sooty blotch in 
> recent weeks because of frequent rains
> and and infrequent appearances of the sun.
> 
>   I have seen similar, but less severe occurrences of the disorder in 
> other years, but would like to hear whether
> others are seeing it this year, or have knowledge of the causes and 
> prevention.
> 
> David Kollas
> Kollas Orchard
> Connecticut, USA
> 
> 
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> 
> -- 
> Maurice Tougas
> Tougas Family Farm
> Northborough,MA 01532
> 508-450-0844
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Re: [apple-crop-2] Apple leaf disorder

[Kari Peter]

It could be Marssonina leaf blotch, which has been appearing in orchards this 
time of year – we first identified this in Pennsylvania last September and I’m 
aware of incidences in NY, NJ, and CT.  It’s rearing its head again this 
season, most likely due to the feet of rain we have received since July.  I 
recently wrote an article for PSU’s Fruit Times:

https://extension.psu.edu/2018-disease-update-marssonina-blotch-on-apple-trees

Moral of the story:  treat it like you would deal with apple scab.  Sanitation 
will be key keeping this disease in check year to year.


Kari Peter, Ph.D.
Assistant Research Professor - Tree Fruit Pathology
Department of Plant Pathology and Environmental Microbiology
Penn State Fruit Research and Extension Center
290 University Dr., P.O. Box 330
Biglerville, PA 17307-0330

Office: 717-677-6116 Ext. 223
Fax: 717-677-4112
E-mail: 
ka...@psu.edu
Twitter: https://twitter.com/drtreefruit




From: apple-crop-boun...@virtualorchard.com 
 On Behalf Of maurice tougas
Sent: Tuesday, October 09, 2018 12:36 PM
To: Apple-Crop discussion list 
Subject: Re: [apple-crop-2] Apple leaf disorder

Yup seeing same here. No captan or phosphorous . Goldens but I don't recall 
seeing on Jonagold. Ill check.

Mo Tougas

On Tue, Oct 9, 2018 at 12:26 PM David Kollas 
mailto:kollasorchar...@gmail.com>> wrote:
The photo below, taken yesterday in my orchard, shows a Jonagold tree among 
other Jonagold trees that
are dropping leaves.  Severity varies from few to many leaves showing the spots 
and leaf-drop on different trees.
Similar, but less severe symptoms appear in other varieties that have yellow 
delicious in their heritage.  I suspect
it to be a fungal infection, because the spots appear on green leaves, which 
then turn yellow and drop.  Frequent
captan plus phosphorous acid sprays have been applied for sooty blotch in 
recent weeks because of frequent rains
and and infrequent appearances of the sun.

I have seen similar, but less severe occurrences of the disorder in other 
years, but would like to hear whether
others are seeing it this year, or have knowledge of the causes and prevention.

David Kollas
Kollas Orchard
Connecticut, USA

[cid:EA50C707-49A2-4BBA-AC36-0B822B1841AC@hsd1.ct.comcast.net]
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--
Maurice Tougas
Tougas Family Farm
Northborough,MA 01532
508-450-0844
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