Plums white and mouldy?

GaryP · May 18, 2019

Hello Everyone

I have a problem with my plum tree. Last year I had exactly the same problem. Many of the small plums have grown OK but about half look bigger and elongated and have turned white with a green mould on them. Any suggestions on this and if the OK ones will go the same way?

Marley Farley · May 18, 2019

Hi @GaryP and Welcome to GC.. I have not seen that before, but wondering if it is something called PlumPocket

PLUM POCKET

Relatively unknown in garden cultivated plum trees in the UK, Plum Pocket is becoming increasingly common. The symptoms are quite unusual and hard to mistake for any other pest or disease. Young fruit begin to to appear longer than normal and slightly larger, this normally becomes visible around mid June time. The next symptoms are white marks on the skin of affected plums, this is a fungus forming. Soon after the plums will begin to wither and die. Normally only around 50% of the plums are affected.

Plum fruit affected by Plum Pocket

Both the picture above and below are courtesy of GardenFocused reader Walter A who is quite clearly a better photographer than I am! The above picture show young fruit on the right developing in the typical elongated fashion. The left hand plum is more developed and is clearly suffering from Plum Pocket.

Plum Pocket - no fruit stone has formed

If the fruits are cut open at any stage no stone will be found, just an empty "pocket" of white flesh as can clearly be seen from the picture above. As the plums wither they turn brown and fall off. The disease is caused by the fungus Taphrina pruni and affects plum and damson trees.

LIFE CYCLE OF PLUM POCKET

The spores of the fungi are spread through air and water from nearby affected trees. It is more commonly found on wild plum and damson trees so if you have any nearby take a careful look at them for signs of infection. The spores become airborne in early spring, land on your tree and lodge in the bark and newly forming branch buds. There they stay, causing no damage, until the next spring. They then multiply and begin to attack fruit buds and young fruit and cause the damage mentioned above.

TREATING PLUM POCKET

The spores of the fungi are spread through air and water from nearby infected trees and also from the affected tree itself. Once the fruit are initially affected there is no way to save them that year. Treatment is aimed at limiting the spread of the spores and at the same time spraying the tree before fruit buds form in early spring.
The first course of action is to remove and burn all affected fruit including those which have fallen to the ground. Take a close look at the tree and if you notice any unusually thick clusters of twigs growing from branches, prune them off because in all likelihood they are infected. As part of the normal pruning process remove any twigs and branches which look unhealthy.

A fungicide sprayed onto the tree will also limit damage very considerably. The best one we know of for Plum Pocket is Westland Plant Rescue Fungus Concentrate, the active ingredient is Difenoconazole. Spray the tree once in November and then again in March.

The copper fungicide Bordeaux Mixture has previously been recommended as a spray to prevent Plum Pocket. However it has now (or soon will be) withdrawn from sale in the UK. Currently there are no alternatives which have been scientifically proven to be anywhere near as effective as Bordeaux Mixture

Various alternatives are suggested, for example aspirin solution or milk, but none have been proven to have any effect
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GaryP · May 18, 2019

Hi.
Many thanks. That certainly sounds like it, I remember them going brown last year and having no stones. Great to finally have some info on it so thank you again.

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Plums white and mouldy?

GaryP Apprentice Gardener

Attached Files:

IMG_20190518_123601.jpg

Marley Farley Affable Admin! Staff Member

GaryP Apprentice Gardener

Are These Plums?

More plums than we can eat

Victoria Plums/James Grieve Apples

I need help with my plums

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Share This Page

Log in or Sign up

Plums white and mouldy?

GaryP Apprentice Gardener

Attached Files:

IMG_20190518_123601.jpg

Marley Farley Affable Admin! Staff Member

GaryP Apprentice Gardener

Are These Plums?

More plums than we can eat

Victoria Plums/James Grieve Apples

I need help with my plums

What is wrong with my plums?

Share This Page

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