This fruiting olive tree has green bumps on its branches which have appeared. currently mostly only on one lateral but just saw one bump on another branch. Is this some kind of virus? Can anyone identify? It looks like black scale, except it’s the wrong color!
Olive tree: Help identifying green bumps
- Thread starter medulsa
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Looks like a gall called a microspheroblast. Any, it is some kind of gall.
.. and should we be worried?!
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I know next to nothing about microspheroblasts except that they are not harmful.
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Is it true that I should not be worried about microspheroblasts on my olive tree ? They’re far from being attractive , is there anyway to stop these bumps from spreading ? Help , Joann ...... December 15th 2021
Greetings medulsa and Microspheroblasts, welcome to the Forums.
The only references for 'microspheroblasts' on Google is the one linked above, and now also this Forum thread. So for now I will just call these growths 'blisters'.
I also found one other reference on another site of someone discussing similar blisters on their Olive (Olea europaea).
The response suggests that these blisters are a bacterial disease called Olive Knot (Pseudomonas savastanoi).
However, the knots formed by Olive Knot look very different in both appearance and location on the tree.
https://permies.com/t/140158/Olive-tree-small-green-bumps
medulsa, I presume you dissected the blisters that are open in the second image of the OP. Thank you for doing so, as this let's us know that the blisters are hollow.
These blisters might be the result of a secondary organism (fungi, bacteria, etc), but another possibility is that occasionally, naturally gas exchange escaping from lenticels on the tree's trunk becomes trapped under a layer of bark. This is just a hypothesis. At the moment we have multiple hypotheses to investigate.
It does seem like this phenomenon is both uncommon and not seriously harmful to the tree, or there would be more images and discussion about it.
The only references for 'microspheroblasts' on Google is the one linked above, and now also this Forum thread. So for now I will just call these growths 'blisters'.
I also found one other reference on another site of someone discussing similar blisters on their Olive (Olea europaea).
The response suggests that these blisters are a bacterial disease called Olive Knot (Pseudomonas savastanoi).
However, the knots formed by Olive Knot look very different in both appearance and location on the tree.
https://permies.com/t/140158/Olive-tree-small-green-bumps
medulsa, I presume you dissected the blisters that are open in the second image of the OP. Thank you for doing so, as this let's us know that the blisters are hollow.
These blisters might be the result of a secondary organism (fungi, bacteria, etc), but another possibility is that occasionally, naturally gas exchange escaping from lenticels on the tree's trunk becomes trapped under a layer of bark. This is just a hypothesis. At the moment we have multiple hypotheses to investigate.
It does seem like this phenomenon is both uncommon and not seriously harmful to the tree, or there would be more images and discussion about it.