Brown blossom rot plum tree

Asked July 1, 2019, 12:42 PM EDT

I have a large plum-apricot tree that has thrived, but now is stricken with brown blossom rot. The tree looks healthy, and had masses of white blossoms in the spring, but not one plum fully ripened! (Last year's harvest was meager also.) I've read online about removing all fallen fruit and all twigs that are diseased, and repeated chemical treatments. Sounds like an on-going battle with a continuing resevoir of disease.... The tree is too big for me to remove the top diseased twigs or spray high up. Much as I've loved this tree (makes wonderful jam!), should I go ahead and chop my tree down, then burn it?

Benton County Oregon

1 Response

Hello. If your tree does indeed have brown blossom rot and you are not able to prune out the diseased parts of the topmost branches and apply preventative sprays perhaps it is best to take down the tree. The best way to control this disease is with both removal of diseased twigs and mummified fruits coupled with a couple of sprays during the bloom season. Pruning to increase the air circulation within the canopy of the tree is also recommended as removal of all diseased and mummified fruits. Pruning is recommended during the current growth season as it is easier to distinguish diseased from non diseased parts of the trees while the tree is in leaf. Sanitation under the tree is also important. Rake up, collect, and destroy dropped fruit, mummified diseased blossoms and any parts of the tree that fall to the ground. It may be possible to save the tree if you hire someone to do the pruning and spraying for you but it may be more economically feasible to cut it down and start over with a variety of plum that is more resistant to the disease. The only information I was able to find on resistance to this disease was in a publication from Purdue which stated that in general European plums and hybrids were more resistant that Japanese plums. Keep in mind that other varieties of trees are also susceptible to this disease to include flowering plum trees, cherry, apricot, and peaches. Look around your property or neighborhood for other infected trees.