Apple and chestnut
1. There're dozen of apple trees in our field when we moved in this property. they've borne apples galore bi-annually, like this year. (Last year only few.) I've never spread herbicide or fertilizer on them except trimmed those vertical new borne branches. My question is how to prevent those bumps and black spots on apples (pic. 2) 2. About chestnut, you tole me mines could be also bi-annual fruit bearing. Now it's about time to harvest and I found these pre-matured fruits. There're about a dozen more on three trees and look healthy. My question is how these unhealthy nuts formed? (See pic. 1)
Genesee County Michigan
Some blemishes from frost are impossible to control on apple, but in general I would recommend picking up fruit tree spray at your local hardware store. These sprays combine a fungicide and insecticide and will prevent the most common issues which include apple scab and insect pests like codling moth and weevils. Just follow the instructions carefully.
To clarify--if you are seeing burs fall from the tree that are not mature that is normal--it is called bur drop and typically occurs when they are around golf ball size or a little bigger. While we are sure of the physiological cause, it is likely related to a lack of pollination, limited tree resources or weather events. This is a phenomenon that occurs in many tree crops including cherry.