Czar plum

[Krazy Kernow]

Posted this somewhere but can't find it - probably on the wrong forum

Best crop of plums ever on a 10-year old Czar plum. Hundreds of fruits but most have dark sunken areas, some have a thin 'scab' on them and others have a crystalised clear resin on them. Hopefully a photo is attached and I'd be grateful for any advice/answers on this problem. Could all the symptoms be related?

Thank you

[JONA]

Hi KK,
the sticky resin like stuff on your plums are often the result of pest or weather damage at some time in the fruits development. Are there any signs of a tiny grub inside these plums?
If there is it's usually Plum Sawfly or Plum Moth damage.
The rotting on some plums could be brown rot which will infect any fruits that are damaged in any way.
Changes in weather patterns can cause fruit to split and let this desease enter the fruit too. In heavy crop years the tree will come under stress much more quickly than usual because of the crop load. That's why heavy thinning on these years can be necessary.
Moth attack occurs very early in the fruits life. The female laying her eggs on the fruit very soon after petal fall. By the time you see damage ....it's too late to get at the pest. Sawfly can attack later in the season but is usually not so damaging.

[Krazy Kernow]

Thanks for this John.
2½lbs of fallen plums have only produced one grub. I have cut some of the fruit open and note that the flesh below the sunken areas is a dark red while the rest is still quite green. Every fruit has sunken areas and other damage so it looks as if the whole crop is infected and will need to be thrown out. Gutted to have waited ten years for a crop, only for this to happen. At least I now know the tree will bear fruit (contrary to the advice given by a local garden centre who stated that Czar will never fruit in Scotland) and I'll investigate methods of combatting the moth(s) causing the problem. Do you know of any treatment I could use to prevent a recurrence next year?
KK

[JONA]

I love czar KK. Good mid season plum for us down south.
As regards moth.
You need to spray ten days after full petal fall. It seems ridiculously early...but that's when mum lays her eggs.
With ' global warming' you'll be planting peaches up there soon!!
You already grow the best raspberries.