Re: [apple-crop-2] Photos of dying trees-fireblight- Doug

[Randy Steffens Jr]

Phytophthora is what I thought when I saw those pictures, although I’ve also 
had fireblight infect susceptible rootstocks with similar appearance.  I had 
big problems with Phytophthora in my orchard in Tennessee.  Particularly in wet 
years.  It also got better when we stopped using overhead sprinkler irrigation 
(horrible irrigation decision for middle TN climate).  Virtually everything I 
planted on M26 and MM106 died over a stretch of years.  I ended up converting 
entirely to resistant Geneva rootstocks.  Inspecting/peeling the bark at the 
bottom of the trunk and the roots roots helped me differentiate between 
fireblight and cold injury as outlined here: 
http://treefruit.wsu.edu/crop-protection/disease-management/phytophthora/ 
<http://treefruit.wsu.edu/crop-protection/disease-management/phytophthora/> and 
here https://ipm.illinois.edu/diseases/rpds/812.pdf 
<https://ipm.illinois.edu/diseases/rpds/812.pdf> .

Randy Steffens
Shepherd’s Valley Orchard and Farms (past manager)
Tennessee





> On Jul 23, 2018, at 6:02 AM, Kari Peter  wrote:
> 
> I’m not sure if this fire blight or Phytophthora – this problem and the 
> pictures look very familiar to what I’ve been observing the last 5 years in 
> PA (this is my frame of reference since I started in 2013).
>  
> Another pathogen to keep in mind that is often linked to this sort of mystery 
> tree death/decline is Botryosphaeria spp., either B. dothidea or B. obtusa, – 
> white rot or black rot.  However, this pathogen is not THE cause of the 
> decline.  These fungi are everywhere and typically don’t create any hassle 
> for the tree: These are relatively weak fungal pathogens and they will not 
> cause tree death when the tree is healthy.  They take advantage of weakened, 
> stressed trees – this is when you have tree death. What I have observed is 
> something is going on in the graft union area.  We have been isolating Bot 
> pathogens fire blight and Phytophthora have been ruled out.  The next 
> question is: what ultimately weakened/stressed the tree to make it 
> susceptible to these weak pathogens. 
>  
> We have been studying this rapid decline problem in PA since 2013ish…and 
> there are (still) more questions than answers, I’m afraid.  I wrote about 
> this late 2016:
> https://extension.psu.edu/apple-disease-rapid-apple-decline-rad-or-sudden-apple-decline-sad
>  
> <https://extension.psu.edu/apple-disease-rapid-apple-decline-rad-or-sudden-apple-decline-sad>
>  
> There is not much to add to the above other than we discovered a previously 
> undescribed virus.  However, we do not know what connection, IF ANY, this 
> virus has to the decline issue.  It is very difficult to prove cause and 
> effect with a virus that infects a woody plant; however, we’re trying.  I 
> believe the decline issue is a complex of things occurring (Winter injury? 
> Drought? Herbicide? Rootstocks prone to stress (ie M9)?Etc.), not just one 
> issue.
>  
>  
> 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 
> <https://webmail.psu.edu/webmail/shell.cgi?timestamp=1362517824>
> Twitter: https://twitter.com/drtreefruit <https://twitter.com/drtreefruit>
>  
>  
>  
>  
> From: apple-crop-boun...@virtualorchard.com 
> <mailto:apple-crop-boun...@virtualorchard.com> 
> [mailto:apple-crop-boun...@virtualorchard.com 
> <mailto:apple-crop-boun...@virtualorchard.com>] On Behalf Of 
> wincowg...@centurylink.net <mailto:wincowg...@centurylink.net>
> Sent: Sunday, July 22, 2018 10:09 PM
> To: Apple-crop discussion list
> Subject: [apple-crop-2] Photos of dying trees-fireblight- Doug
>  
> Doug-I looked at the photos you attached and the last photo, #22301at the 
> base just above the rootstock- has long verticle cankers (sunken areas in the 
> bark) and verticle cracking in the bark.  Combined with the tree colapsing it 
> sure appears to be fireblight.
>  
> However you also appear to have significant damage to the rootstock just 
> belowe the graft union when you blow the picture up. Its weedy and from the 
> angle cannot see how much is comprimised.
>  
> I had emailed you a list of questions on this list but I didnt get a 
> response. The purpose was to try and narrow down whats going on.
> You have had much advice, from many on the list.
>  
> The main question is what rootstock is your planting on? If is a suceptable 
> stock with a suceptable root then you have double trouble.The fireblight can 
> run right to the root causing t

Re: [apple-crop-2] Photos of dying trees-fireblight- Doug

[Kari Peter]

I’m not sure if this fire blight or Phytophthora – this problem and the 
pictures look very familiar to what I’ve been observing the last 5 years in PA 
(this is my frame of reference since I started in 2013).

Another pathogen to keep in mind that is often linked to this sort of mystery 
tree death/decline is Botryosphaeria spp., either B. dothidea or B. obtusa, – 
white rot or black rot.  However, this pathogen is not THE cause of the 
decline.  These fungi are everywhere and typically don’t create any hassle for 
the tree: These are relatively weak fungal pathogens and they will not cause 
tree death when the tree is healthy.  They take advantage of weakened, stressed 
trees – this is when you have tree death. What I have observed is something is 
going on in the graft union area.  We have been isolating Bot pathogens fire 
blight and Phytophthora have been ruled out.  The next question is: what 
ultimately weakened/stressed the tree to make it susceptible to these weak 
pathogens.

We have been studying this rapid decline problem in PA since 2013ish…and there 
are (still) more questions than answers, I’m afraid.  I wrote about this late 
2016:
https://extension.psu.edu/apple-disease-rapid-apple-decline-rad-or-sudden-apple-decline-sad

There is not much to add to the above other than we discovered a previously 
undescribed virus.  However, we do not know what connection, IF ANY, this virus 
has to the decline issue.  It is very difficult to prove cause and effect with 
a virus that infects a woody plant; however, we’re trying.  I believe the 
decline issue is a complex of things occurring (Winter injury? Drought? 
Herbicide? Rootstocks prone to stress (ie M9)?Etc.), not just one issue.


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<https://webmail.psu.edu/webmail/shell.cgi?timestamp=1362517824>
Twitter: https://twitter.com/drtreefruit




From: apple-crop-boun...@virtualorchard.com 
[mailto:apple-crop-boun...@virtualorchard.com] On Behalf Of 
wincowg...@centurylink.net
Sent: Sunday, July 22, 2018 10:09 PM
To: Apple-crop discussion list
Subject: [apple-crop-2] Photos of dying trees-fireblight- Doug

Doug-I looked at the photos you attached and the last photo, #22301at the base 
just above the rootstock- has long verticle cankers (sunken areas in the bark) 
and verticle cracking in the bark.  Combined with the tree colapsing it sure 
appears to be fireblight.

However you also appear to have significant damage to the rootstock just belowe 
the graft union when you blow the picture up. Its weedy and from the angle 
cannot see how much is comprimised.

I had emailed you a list of questions on this list but I didnt get a response. 
The purpose was to try and narrow down whats going on.
You have had much advice, from many on the list.

The main question is what rootstock is your planting on? If is a suceptable 
stock with a suceptable root then you have double trouble.The fireblight can 
run right to the root causing tree colapse. With those cankers visible in the 
lower trunk this looks like what you have.

My guidance to growers with this combination, suceptable stock with suceptable 
root is take the tree(s) out.

You also indicated these were in clusters, again sounds like fireblight, the 
inoculumn moves to the trees next door and take it out.

The soil born disease phytophora can cause a similar looking tree colapse, but 
will not have the cankers in the trunk. Also is is born in the soil water and 
usually runs down a row if there is any slope.

There are many good labs, both univ and private that can id both fireblight and 
phytophora if the get live tissue samples. You need to confirm what you have so 
you can plan control programs.



I would certain







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[apple-crop-2] Photos of dying trees-fireblight- Doug - resent and complete

[wincowg...@centurylink.net]

The first response sent too quick by mistake, here is the complete email———

Doug-I looked at the photos you attached and the last photo, #22301 (see below) 
at the base just above the rootstock- has long vertical cankers (sunken areas 
in the bark) and verticle cracking in the bark.  Combined with the tree 
collapsing it sure appears to be fireblight.  Mo Tougas echoed this question.

However you also appear to have significant damage to the rootstock just below 
the graft union when you blow the picture up. Its weedy and from the angle 
cannot see how much is compromised. This can be caused by herbicide, mechanical 
injury, winter injury or all the above and could contribute to tree collapse.

I had emailed you a list of questions on this list but I didn't get a response. 
(See list below from July 18 email.) The purpose was to try and narrow down 
whats going on.
You have had much advice, from many on the list.

The main question is what rootstock is you're planting on? If is a susceptible 
stock with a susceptible root then you have double trouble.The fireblight can 
run right to the root causing tree collapse. With those cankers visible in the 
lower trunk this looks like what you have.

My guidance to growers with this combination, susceptible stock with 
susceptible root is take the tree(s) out.

You also indicated these were in clusters, again sounds like fireblight, the 
inoculumn moves to the trees next door and take it out.

The soil born disease phytophora can cause a similar looking tree collapse, but 
will not have the cankers in the trunk. Also is born in the soil water and 
usually runs down a row if there is any slope.

There are many good labs, both Univ. and private that can id both fireblight 
and phytophora if the get live tissue samples. You need to confirm what you 
have so you can plan control programs.

I would remove all infected trees and burn, sample for lab first- 

Check trees for FB cankers and remove if you find.

There are spray programs to harden off fireblight shootblight. Certainly both 
shootblight and blossom blight programs should be implemented next year 
beginingbeginning with copper sprays very early, Apogee program beginning at 
Pink for shoot blight, and blossom blight using Newa or forecasting programs to 
predict spray applications of antibiotics and SAR products until all bloom is 
gone, and then post bloom control programs.

See also our fact sheet that covers all these pieces for control:
An Annual Fire Blight Management Program for Apples

https://ag.umass.edu/fruit/fact-sheets/annual-fire-blight-management-program-for-apples

If you wish do discuss in detail please contact me.

Best,

Win 

Win Cowgill
Apple-Crop co-founder 
Professor Emeritus, Rutgers, the State University
Visiting Scholar, UMASS-Amherst
CEO- Win Enterprises International, LLC
Editor Horticultural News
PO Box 143
Baptistown, NJ 08803
Office 908-489-1476
Fax- 908-996-6404
Email: wincowg...@mac.com
www.wincowgill.com
www.virtualorchard.net/
http://giselacherry.com/ 
http://virtualorchard.net/njfruitfocus/index.html
http://www.appletesters.net
http://nc140.org
Twitter  @mrsuncrisp 


> On Jul 20, 2018, at 11:16 PM, Doug Nelson  > wrote:
> 
> hugh makes me think i dont have fire blight given his description. What I 
> have happening is clusters of trees (about 4 or 5 per cluster in 3 different 
> clusters) across my 6000 tree orchard. When the tree becomes symptomatic all 
> the leaves brown and the entire tree seems to dies withing 5 days- all the 
> leaves become droopy then brown at once. Maybe this is something else 
> happening? Attached are pictures.
> 
> 
> 
> 
> 
> On Thu, Jul 19, 2018 at 7:45 AM Kari Peter  > wrote:
> Pruning out fire blight this time of year can be tricky depending how much 
> fire blight you are pruning out.  Excessive pruning will encourage more shoot 
> growth = more shoot growth means susceptible shoots to fire blight right now 
> especially with conditions favorable for disease.  Trees should be hardened 
> off right now meaning new shoot growth should be finished.  When this occurs, 
> the bacteria stops moving in the trees and new fire blight incidence should 
> stop.  I would highly recommend avoiding doing anything that would encourage 
> new shoot growth right now.  If it were me, I would just wait until the 
> dormant period to aggressively remove everything.  There is much debate about 
> cleaning pruning shears between cuts.  I don’t recommend it because the 
> bacteria can move 3 feet beyond the site of visible infection, so 
> disinfesting is a moot point.  Here is my latest article (June 26, 2018) in 
> Penn State Fruit Times about what to do about fire blight now (it’s just 
> below the info about apple scab):
> 
>  
> 
> https://extension.psu.edu/mid-season-tree-fruit-disease-update 
> 
>