Plum Tree - Gummosis.

[GF3]

Hello.
I have a Plum Tree (Blue Tit) that has been in the ground 4 years. And I think it has "Gummosis". It is on the lower trunk in two places. It looks to me as if it is at the graft point. I have uploaded two photos taken today.
Any advice what my next move should be?
Many Thanks.

[ameno]

There's not really any specific action you can take. Just keep it fed and hope it doesn't become anything more serious.

[GF3]

Thanks for the reply.
Today I scraped off the resin and I had a closer look at the tree. Looking closer at the trunk, just above the graft point, I could detect a cavity/hollow about 2 inches long, just below the bark. The bark gave when I pressed on it and resin oozed out. I have highlighted the area in the photo below.
Reading on the RHS website, it could well be bacterial canker. As it refers to sunken areas of bark.

https://www.rhs.org.uk/disease/bacterial-canker

On stems and spurs: Sunken, dead areas of bark develop in spring and early summer, often accompanied by a gummy ooze. If the infection spreads all round the branch it will die rapidly. However, it should be noted that gum production (gummosis) from the bark of Prunus species is actually quite common, and in the absence of dead, sunken bark is likely to have resulted from causes other than bacterial canker, for example physical damage or environmental stresses

If it is bacterial canker could this infect apple trees? Or just other stone fruit trees?

[ameno]

The canker which affects apples trees is a different species, so you should be fine.

I wouldn't worry too much about the gummosis for now, though. It's usually not fatal, even when accompanies by sunken patches of bark.

[It never rains..it pours]

I had similar on a jubilee plum but it was 2ft up the trunk. Cut it out and the bark has grown back over, over a couple of years. It was about 20% of the bark circumference that I had to cut out
Have four plum varieties here and jubilee clearly is the most disease susceptible
Think I read Blue Tit is quite disease resistant.

[GF3]

Many thanks for your replies.
I shall keep an eye on things for now, see how it goes. If it gets worse I will probaby try and cut it out.
Yes, Blue Tit is said to have good disease resistance - it was my reason for buying that variety. But, as I have previously posted on here, I bought it from Chris Bowers - so it may not be Blue Tit.
Many thanks again.

[ameno]

Has it produced any fruit yet since you bought it?

[GF3]

I bought it (bare root) in December 2019. I planted it in a large container. I planted it in the ground April 2021. It produced a few plums in 2022 only one survived. It tasted very good and matched the description of the Blue Tit plum. The others about 10 or 12 grew no bigger than a baked bean before they fell off. In 2023 it produced another dozen or so baked bean size plums - none survived. This year, again a dozen or so tiny ones with just one surviving.

[It never rains..it pours]

Do the leaves have lots of holes ?

[GF3]

Do the leaves have lots of holes ?

No. The leaves look fine. The tree appears to be growing well. In previous years I have had trouble with leaf curl aphid. This winter I sprayed with a neem oil mix and the leaves have been ok no aphids and growing well. The single plum that was left has withered and fell off. The Gummosis is still happening. It is coming out at three points around the trunk.

[It never rains..it pours]

Sounds very similar to my jubileee, leaf curl aphids loved it unlike the other plum trees but a winter wash sorted them out
However it did get shot holes this year, think was the wetter summer, and we ended with no jubilee fruit making it to harvest
Seems the better the fruit the worse for disease. Our opal is more disease resistant and reliable. Have a marjories seedling that is due to crop next year that looks more hardy but apparently poorer tasting than an opal