Unripe plums falling from tree

Question

Any reason the the unripe plums on our are falling off, Tree is around eight years old.

Roger

Answer 1

There can be numerous reasons why a plum tree drops its fruit before it ripens: insects, disease, high winds, and stress ( too much water, too little water, lack of nutrients, poor drainage, weed competition, and excessive shade). But the most common reason -- especially when, as you say the tree is heavily laden -- is that the tree has produced more fruit than it can support. If this happens again, you'll want to thin the fruit.
When the fruit reaches about 3/4-inch in diameter, pick off extra plums so that the ones that remain are about 4 or 5 inches apart.
https://www.gardeningknowhow.com/edible/fruits/fegen/reasons-for-small-hard-fruit.htm
https://www.gardeningknowhow.com/edible/fruits/plum/plum-tree-diseases.htm
https://www.gardeningknowhow.com/edible/fruits/plum/plum-curculio.htm