Identification of Lime tree defects

[gulvain]

I was wondering whether anyone can help me identify the defect in the enclosed photographs.

 

It was sent to me by a colleague for a site I have not visited. He reports that there are a number of lime trees with what appear to be borer holes of around 2cm. If anyone could help I'd be grateful.

[daltontrees]

2cm deep or 2cm diameter?

[Gary Prentice]

With the tree size and location of the wound, my initial thoughts would be that these are mechanical/man made wounds, rather than an insect. I may be wrong!

[daltontrees]

That's why I am querying the size. I wouldn't like to meet an insect capable of a cm diameter bore or even an exit hole, but I can easily see some clumsy increment boring doing this.

[Gary Prentice]

I think ALB are fairly big, but.....

 

Why would anyone want/need to put an increment borer into such a small stem. ( L6 student doing a research project on transplant shock and reduced growth maybe:biggrin:)

 

Edit: The second tree is planted too deep too.

[gulvain]

2cm across I believe. I haven't seen the trees myself but my first thoughts was that the holes look too large for a borer, and I would have expected to see more holes with shavings at the base. I did wonder whether it could have been a formative pruning wound (even though I can't see any sign of a former branch collar).

 

Thanks for the advice about the depth of planting. I'd like to give my colleague a clearer suggestion about what's caused the damage though. Apparently it is on a number of trees.

[treeseer]

Look at the sunken are below the hole. I agree with Gary re root related. Your colleague can get a clear idea of the cause if the take a trowel and dig away all the dirt off the stem.

No inspection, no diagnosis.

[daltontrees]

I'm going with William of Occam on this and saying someone has drilled holes in the trees. Reason could be to test starch reserves (I have done this myself with a 15mm auger drill bit, but only on trees that were condemned anyway). The shavings are of course taken away for analysis. A closer look at the holes that shows they are of uniform diameter would be allthat is needed to back up the hypothesis.