My plum tree is losing its fruit. The plums reach about 1" to 1/1/4" by maybe about 1/2" in diameter. This has been happening every year but I was derelict in caring for it previous to this year. I have sprayed it three times already since spring with a "Fruit Tree Spray" containing Insecticide, Fungicide and Miticide, made by a company called Green Light. I have been removing "Black Knot" branches each year and have had problems with Aphid infestation. It may already be too late, as at least between 5 and 6 dozen plums have fallen so far, but maybe you can set me straight for next year.
Certified GKH Gardening Expert
It sounds like it may be a pollination issue. The tree will abort the fruit if not properly pollinated. Depending on what kind of insecticide you used, you may have made the tree inhospitable to pollinators, so they could not do their job. This article will help with attracting more pollinators to the tree: https://www.gardeningknowhow.com/garden-how-to/beneficial/creating-a-pollinator-garden.htm