Q.My Victoria Plum Tree Leaves Are Going Black And The Fruit Have Fallen Off What Can I Do?
only moved here 2 years ago the trees were small in pots I planted them as soon as we moved the soil is very sandy , I planted them in the lawn where the moles had dug the earth up . Last year had really good crop this year all the fruit have fallen off and the leaves have started to tun black. There are only 2 tree and hope they can recover.

Certified GKH Gardening Expert
Since they are in the lawn, remove the grass out to the drip line of the trees and fill it with mulch. They are vulnerable to mower or weed eater damage the way they are. Also, if you fertilize the lawn, be careful not to fertilize the tree with it, especially if it is a weed and feed type which has an herbicide in it. Since you have sandy soil, it would help to sidedress the trees with compost. The leaves resemble fire blight damage. Here is more:
https://www.gardeningknowhow.com/plant-problems/disease/fire-blight-remedies-and-symptoms.htm
https://www.gardeningknowhow.com/edible/fruits/plum/growing-victoria-plums-in-gardens.htm
https://www.gardeningknowhow.com/edible/fruits/plum/plum-tree-diseases.htm
https://www.gardeningknowhow.com/edible/fruits/plum/plum-tree-fruit-spray.htm