I have one sweet sixteen apple that's about 15 years old ..The last two years it produces a lot of apples and when they get the size of a golf ball ,then 99% fall off some time in June What is causeing this ..I do have a ceder tree about 25 yards away from it ,could that be making the apples fall?? Or is there somthing else doing it?? Richard Wilts
The June drop is a natural occurence. The tree will drop any fruit it feels incapable of maturing. 99% drop is very unusual, look for something stressing the tree. I would wonder about either too dry or too wet around the roots.
You might cut open some of the dropped fruit to check for pest larvae. Tart Cherry trees often drop fruit that has been stung (egg-deposit) by Plum Curculio; external evidence of this can be seen by a small, crescent-shaped mark on the outside. Apple Maggot may be another pest in your area. Its larvae is vermiform, has a pointy head. Your University Extension agent would be a good person to ask about this problem. Something I am going to experiment with this year is the use of apple bags; here is one source: http://www.fedcoseeds.com/ogs.htm
