The story begins with a letter.
“Hello Dan. Three years ago I bought from you 2 plum trees (1 Czar and 1 Marjories Seedling) and 1 apple tree (Bountiful) and now they have grown into sturdy trees. The Czar and Bountiful produced prolifically last year and the Marjorie Seedling less so, but this year it appeared that all three would produce magnificent crops (despite the best efforts of wood pigeons to strip the plum trees of their leaves). However, two weeks ago or so I noticed some brown patches on my Czar plums which have further developed and spread, and I am 99% certain that the tree is suffering from brown rot. Worse I am pretty certain that it has also spread to the other two trees, although it is in a less advanced state.
“I have removed the fruit concerned and I have sought information on the internet for a cure. However, all the advice is that, because this is a fungus, no cure is available. I understand that I may have to accept that I will lose this year’s crop and my main concern now is how to prevent a recurrence of the problem next year, if indeed prevention is possible. Any advice you have on what I can do in this respect would be greatly appreciated. Thank you for any help you can provide. Yours sincerely, B.G.”
I of course remembered the trees that we had supplied, and the location, and so I wasn’t sure about the inception of brown rot. This is what I wrote back:
“Hello B. Usually brown rot only occurs on fruit which is nearly ripe to eat. I am therefore not at all sure it is indeed brown rot. In order to be more positive, please send me some pictures attached to your next email. I will need a picture of the tree as a whole, a close up picture of the leaves and another picture of the worst affected fruits on the tree.”
Here are the photos that Mr. B.G. provided:
And here are the photos of the Marjorie Seedling:
The photos clarified the situation, and I was able to write back to Mr. B.G. immediately.
“Thank you for the pictures. Yes I do know what has happened. But first the good news!
There is nothing wrong currently with your tree; good dark green foliage and good sized leaf.
The bad news is the fruit which has been totally destroyed. The cause is the spores of the fungus ‘Brown Rot’. Earlier in the season you must have had a hailstorm. The pit marks on the fruit are visible on your photos. Wounds in plum fruits do not heal. Brown Rot fungus spores are in the air, throughout the growing season. After the hail the fruit got infected with these spores and I am afraid destroyed your crop. The points you should consider are the following;
1) Look out for a stump or old plum tree in your area, which could be the source of infection. Destroy that tree.
2) Thin your fruit to 2 per cluster as a standard procedure by the middle of June in any year. Space these doubles 6 inches apart. Brown rot fungus thrives in clusters of fruit.
3) If hail occurs again next year, spray without delay with Systhane fungicide. Once the spores get in the wounds it is too late. You can purchase Systhane from Amazon for little money!
4) Do remove all affected fruits as soon as possible from your garden. The fungus will overwinter on the fallen fruits and be ready to infect next year’s crop.
5) Water the soil under your tree during dry hot periods. If the soil dries out and then rain follows, the fruit will split and as a result, create enormous points of entry for brown rot spores.
6) Spray your fruit trees before leaf fall in November with Bordeaux mixture. This will safe guard the tree against silver leaf and bacterial canker infections.”
So, all clear. The hunt is on for the rotting plum tree stump that caused it all!