Reaction scarring on Hippocastanum

Garry Brockley

I Thought we deserved something to get our teeth into so i finished early and posted this.
I got to look at this Hippocastanum today it is covered in reaction growth up to the end 6 feet of every limb. the top third looks like its dieing off but the lower limbs are showing healthy leaves.




so I climbed it and took a sample from the upper 6 feet and disected it at home the pictures are through my 5x lense and camera phone. In the first you can see an empty larva caseing, then you can just see the little blighters wandering around as i dug them out of the nooks and crannies.




The question is do these attack healthy wood and would they stimulate the reaction growth shown?

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Garry Brockley

ok no ideas never mind! im dismantling it when i get back, i feel a mass disection coming on learn some more about diseases in trees!

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treeseer

I was stumped--should be fascinating to learn whether the larvae are pathogenic or saproxylic; i tend toward the latter.

Cool pics, good project for study!

Are you taking the whole tree down? It'd be interesting to see how it responds to a reduction (though maybe not for the tree owner)

Garry Brockley

local auth tree officer wants a 50% reduction on it but this will cause more harm than do good and look bloody awful; i dont want my name attached to that look it would be a pollard job basically the ho would just like it out and a new one in its place. which is fair enough really.

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pcarborist

looks like bacterial crown gall.

Garry Brockley

i wasnt aware that large specimens like hippocastanum would carry that type of Gall, wow, ok so it is possibly a form of Agrobacterium tumefaciens similar to the bacterial infections you get in fruit trees only more advanced, ive never seen any that is so prolific within a plant, but then again they would be removed asap if they were in an orchard and wouldn't have the chance to spread and damage the plant for so long, So because of the deformation of plant tissues due to gall formation this woulld disrupt the movement of water and nutrients between roots and leaves. The stems are weakened and growth would be reduced and there would be a general decline in leaf producing vigor. thats why the top of the crown is looking sparce and unhealthy Der i wish i had a brain that works

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