Sudden oak death in The Netherlands

[Treespotter]

Is this the dreaded Sudden Oak Death? If so, we have a very big problem here.

The pictures are all taken of seperate trees standing in one cluster of 10x10 yards. The trees are approximately 150 years old.

 

Wolter

[treeseer]

Looks to be a soilborne disease; Phytophthora or some other organism. When the stem is covered with soil and wounded by turf equipment, soilborne organisms enter the tree. Not good, but treatable.

 

...Are those

black droplets fresh paint or something? They look so

shiny. ?”

“To realize that you do not understand, is a virtue,”

Ru noted, quoting the Tao Te Ching.

I nodded as I pulled a chisel out of my bag. “Those

black droplets are coming out of ‘bleeding lesions.’ It

looks like a soil-borne organism, such as Phytophthora sp.,

is colonizing the phloem tissues under the bark. These

lesions are a structural concern, because we already know

that interior decay is near the surface. This pest should be

managed with IPM treatments aimed at compartmentalization.”

I flipped through pages 354–367 of my book on

diseases. “‘Remove soil from stem tissue, dry the area,

deeply aerate nearby soil, clean and heat the lesions, and

amend the soil with calcium fertilizer and beneficial

microorganisms to help speed compartmentalization.’”

 

To that I might add, replace the soil against the stem with permeable aggregate, and cover with rosaceous mulch, per research from the UK.

[treeseer]

Context here http://www.historictreecare.com/wp-content/uploads/2012/05/DD-LLL-1406.pdf

[jomoco]

This article indicates that SOD's been active in the Netherlands for some time now Wolter, though not necessarily in Q. alba, but Rhododendrons for sure.

 

http://www.mfc.ms.gov/sites/default/files/TB39_Sudden_Oak_Death.pdf

 

I've had pretty darn good results treating Q. agrifolias infected with SOD far worse than your pics of Q. alba indicate, using a fungicide called Agri-Fos as a basal systemic drench.

Agri-Fos is the only fungicide I know of labeled for use against SOD by the California Department of Forestry.

 

I mix it at a one to one ratio with water, and add 7 ounces of PentraBark surfactant to every two gallons of mix. Simply spray the trunk till drenched from about ten feet high to the ground. Once in the spring, then again in the fall.

 

Jomoco

[Treespotter]

The black spots on Fagus ar known for me at least 20 years. On Quercus for about 10 years. Most of the times I thougt it was triggered by Armillaria ostoyae in later years I learned Phytophthora was the culprit. The last years I realised Sudden oak death was the name given to the problem. The problem was here but never in lots and lots of trees. Until......

Last year and this year I see the black spots popping up virtually everywhere. Not just at some places but lots and lots of places.

 

 

Wolter

[treeseer]

Same here; on more species and not just in drainage-challenged areas but here and there.

 

I may be wrong but I am guessing that since it is a soilborne disease (whatever the species), then it can only help to break the soil-stem connection by getting the dirt off the trunk, and replacing the soil >15 cm away from the flare.

 

Both P and A travel in water, so drying the flare seems logical to try, along with phosphorous acid, which is registered for use. We've had good results in several individuals, but no huge databank of results, and with no replication or controls, there it is!

 

I saw a few trees in Vonderland and other parks in Amsterdam that had bleeding lesions, but no epidemic or anything.

[Treespotter]

Guys, guys, what are you talking about. The trees in the pictures are standing in the best drained soil there is. There is zero dirt on the stems. These trees have been there in the same situation for 150 years.

 

Wolter

[jomoco]

You must mean Guy, Guy, what are you talkin bout..

 

Jomoco

[AA Teccie (Paul)]

Hi,

 

I recently heard Henry Kuppen from Netherlands speak very authoritively on OPM but got the impression he does a lot of other stuff too

 

see http://www.kuppen-bomen.nl/ziekte-plaagbeheer/httpwwwkuppen-bomenceasarnlziekte-plaagbeheerinsec.html which may be worth a contact

 

Regards..

Paul

[Treespotter]

Haha, thanks Paul. Henry and I go way back. He was my mate while working at Copijn back in 1986. We never lost contact. That can't really happen in The Netherlands with our close friends arborist community. 😉

 

Wolter