What may have caused this hole in the trunk of this Avocado?

[mbmango]

The white crust was originally a mound and when I touched it (very lightly), most of it fell off exposing this hole.  What might be causing it?

[gnappi]

The white crust was originally a mound and when I touched it (very lightly), most of it fell off exposing this hole.  What might be causing it?

A friend of mine had a HUGE plume like this in her avo, she let go way too long and finally she got worried about losing the tree, its leaves were curling and it was defoliating, so she called me. I took the pic below.

Nobody locally I spoke with knew what it was, and the county ag servive couldn't help her. I went there hosed it down with a jet of water, and soaked it with plant doctor. I left my sprayer with her and she sprayed it every day till the gallon mix was gone. It stopped leaking that white crusty ooze and it fruited fine this year.  I don't know what you have but if I were you I'd call an arborist (my friend refused to pay one) as soon as possible.

[Vernmented]

http://lmgtfy.com/?q=avocado+fusarium+
I am guessing this is it. I got some after hacking away at mine with a bunch of grafts when it was raining a lot.

[barath]

The white crust was originally a mound and when I touched it (very lightly), most of it fell off exposing this hole.  What might be causing it?

Is it a recently purchased tree from the store?  (Say in the 1-3 years?)  If so, it could be canker:

http://www.cloudforest.com/cafe/gardening/beware-fwg-hass-avocado-trees-tainted-with-mites-and-canker-t6000.html

I haven't seen what canker looks like on hardened wood, only on green wood, so I'm not quite sure from the picture.  But there's been a lot of commercial nursery trees affected.

[mbmango]

The Holiday avocado was just planted last May (15g) so it is still young, with that picture being of the main trunk.  The tree itself seems to be doing well still, although it had recently dropped a lot of leaves which I thought was due to the hot spell a month or so ago.  I was checking in on a single fruit I had left on it, which happens to be above the injury point.  I've never grown avocado (to fruiting), so should it be left on till next year?  It seems a good size already. 

I will try "cleaning" out the wound tomorrow to see what kind of visible damage is in there.  I don't think I'd call in an arborist for such a young tree.

[Rtreid]

Looks like a canker to me, either citricola or dothiorella. The people at the UC  Cooperative extension (I would suggest the OC or Riverside branches) could probably give you a positive ID and treatment method, although I have had pretty good luck with phosphite salts (Agri-fos or similar) for a lot of unknown fungal and bacterial problems.

RIchard

[mbmango]

Sprayed it with a hose to see if I could see anything underneath but it just looks like a wound, as if a branch had fallen off and not healed properly. The tree had a much larger scar higher up from last year that has totally healed over this year.  I don't see any entry/exit holes, but I may just not be able to recognize them.  I had contacted Dr Eskalen from UCR (http://eskalenlab.ucr.edu/avocado.html) and got a reply, so I'll see if I can figure it out.

And the fruit also fell off on its own (stem was partially dried up or blackened), or was knocked off, so hopefully it will turn out to be edible.

[mbmango]

Scraping some bark to get a better picture of the wound, but it went in a good amount.  UCR opinion is a canker (http://eskalenlab.ucr.edu/handouts/avocado_branch_canker_disease.pdf).  I wasn't advised of a specific treatment, so will go with Richard's advice.