Is this something to be concerned about ?
Mt Royal EU Plum has a couple places with amber oozing thru the bark. And one spot where a square of bark seems to have pealed off ?
I read online that this is somewhat common for stone fruit and is often caused by hot/sunny/dry conditions…
We have had some of that. We had 4-5 weeks of no rain recently… then a couple rains… and now it is hot and dry again.
The amber is not runny at this point… it is quite hardened.
My Rosy Guage died this spring… some kind of wilt… now this on my Mt Royal.
I dont normally have to water fruit trees… but then there are years like this where i probably should.
More mulch… water it a few times good.
It does not look like insect damage to me (borer ?)… but I have no real experience with that.
If it is a borer… how do you tell ? What do you do to get rid of it ?
With borers, one expects to see insect poop (frass) that may look like sawdust and if frass is mixed with the sap, it wouldn’t look so clear. If your rootstock is peach it may be a target in the future.
There’s quite a few borer threads on this forum. Most people posted picture of manually removing the borer with a wire (e.g. an unraveled cloth hanger). Some used an insecticide like Sevin. Some use raw neem painted on trunk.
Going back to the sap, I have observed in heavy rain, my stonefruit trees may squeeze some sap out. So sometimes it could happen like that too. You might check after the next big rain.
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@sockworth … I will take a closer look at it tomorrow. Thanks
I lost a plum tree to gummosis several years ago. Started out looking like that, I sprayed the trunk with Lindane and forgot about it. My fault, wasn’t borers, was fungal or bacterial and spread to ‘Emerald Beaut’ plum. Sprayed limbs well for both several times throughout the year. Next year it looked much better.
Definitely not borer, you’d see either a hole in the very early stage, or a toothpick protrusion of wood (insects gotta 
too).
What happened to the bark there? Was there damage done to the tree? If so, it’s likely just the tree protecting itself.
Someone with more experience could chime in on the potential of it being bacterial canker, but I don’t see any necrosis (black or rotting tissue around the wound) so I’d guess you’re fine.
Hopefully just gummosis and not canker. I have some stonefruit that will ooze from heavy rain and injury. On the other hand i had to cull an EU plum because it was canker ridden to hell and back again. The more I torched it the worse it got. I did torch the living hell out of some canker on a black gold cherry tree and its now thriving and doing very well!
@kybishop … not sure what happened to the bark there… that square area just seems to have pealed off… with no physical injury that i know of.
I did take a closer look at it yesterday … did not see anything that looked like frass or sawdust or borer holes…
I scraped the hardened amber off and checked underneath it and this is what it looks like.
I watered it good and today going to pull the mulch back and give it a wheelbarrow full of mushroom compost… and another wheelbarrow full of wood chip mulch on top of that.
That should help it retain as much moisture as possible.
Do those spots look like borer damage ?
I am thinking no… but could be wrong.
My help for the tree so far today…
Yes… a wheelbarrow of compost… and another of partially composted wood chips… which has a lot of small limb and leaf material in it.
And a good soaking.
I did put down some balanced organic fertilizer and micronutrient mix on the compost under the wood chips.
This should help it deal with our current hot/dry conditions anyway. Hopefully those places will heal.
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