Thread: What is growing out of the base of this tree?

Can anyone tell me what this might be and what may be causing it?
Would the planting practices used have any relevance?

Please let me state up front that I am not a pathologist. However, I got out my Diseases of Trees and Shrubs by Sinclair and I would suspect...

Crown Gall caused by Agrobacterium tumefaciens, a soil-inhabiting bacterium.

Generally, it seems to be that the tree can co-exist with this unless it gets too severe or another pathogen takes advantage of the weakened state. It appears that the bacteria in the soil or water or on implements infect fresh wounds of any sort. Suitable wounds arise during propagation, transplanting, cultivation, frost heaving of soil or feeding by soil insects or nematodes... (This info taken from above book.)

So I would say that yes, the planting scenario (sharp rocks with frost heaving on young plant bark) certainly could have exacerbated a potential problem. (If this is in fact, crown gall.)

Sylvia

Thanks for your reply Sylvia. I wll definatly look into this.

I guess I should have probably mentioned that this is a Swedish/ Columnar Aspen tree (actually there are several but only two appear to be affected as of yet). Just in case this has any relevance to the condition.

Also, because two of the trees have this and they both appear to still be in the 'sac' they were grown in, would this likely be something that was in the soil which came from the nursery / tree farm/ etc?

The poplar family is one of the susceptible genera so the Swedish Aspen Populas Erectus falls into that category.

When you say the "sac" is still around the tree...is it still tied and tight against the trunk? If so this could definitely have caused injury at the root crown which could have allowed the bacterium to take advantage. But unless all the other trees were bareroot, I would suppose they had the same soil coming from the nursery/tree farm.

Crown gall (Agrobacterium tumefaciens) is a very wide spread, common bacteria (it has the broadest range of hosts of any bacterial plant pathogen) that appears to become opportunistic to individual circumstances. I'll quote from my reference book here: "Young plants with large or numerous galls tend to be stunted and predisposed to drought damage or winter injury." "Damage is greatest when galls encircle the root crown, but few plants are killed by crown gall alone."

Sylvia

Sylvia, you've found the best way to study for the bcma--using the references to diagnose and prescribe.

Savvy lassie.