Lack of pollination or brown rot could be the cause. Plum trees are very particular about their pollinators. They are generally not self-fruitful meaning they need a different plum and often a specific variety for pollination and fruit development.
If the plums were not full size and lacked a seed (stone) this was the problem. Jun 27, Extreme cold during flowering will cause the blooms to drop too early, and a plum tree fails to bear fruit.
Freezing temperatures before blooms. Fruit flies, apple maggots, caterpillars and plum curculio damage the plums, which eventually drop from the tree. Plums damaged by insects are usually scarred or rotted and the causes are easily. Sep 21, The European viral disease called Sharka first entered the U.S. in the late s and causes plums and other stone fruit to shrivel and fall.
The only effective control of sharka or plum pox virus (PPV) involves quarantine of infected orchards and destruction of diseased trees. Aug 23, for a disease. It can cause an entire crop to fall off the tree prematurely where you are. Not so much in commercial operations but in home gardens, we do see Plums that are just starting to turn color fall of the tree long before they are ripe.
It is quite common with the American and Japanese Plums. Jun 15, Most of those will fall off, leaving only two or three apples. If you want better sized apples, you hand thin them down to a single apple on each cluster. But that is a bit off topic. Your plum tree is thinning itself. If it is dry, it will shed more fruit. It takes a lot of energy for a tree to produce fruit.