THINNING FRUIT TREES
Deborah L. Brown
Removing a portion of the fruit from fruit trees often results in larger yields of better quality fruit. Thinning during an "on" year also tends to reduce biennial bearing tendencies of some varieties.
Thinning is best accomplished by hand picking fruits after June drop, about July 1. Where fruits are clustered, remove all but one fruit per cluster. Space fruits from 5-8 inches apart, removing the small insect and disease injured fruit first. Fruits may be spaced closer together on the outside and top of the tree than in the center, because such branches receive full sunlight.
At one time, fruit trees could be thinned by spraying them with the insecticide Sevin two weeks after flower petals had fallen. However, the Sevin label has been changed, and this is no longer a legal use of the product. There is a better product available now, based on the growth regulator, ethephon. It is sold as Florel ® Fruit Eliminator, a spray that must be applied to trees when they're in full bloom.
Chemical sprays will not eliminate all the fruit from a tree. Hand thinning is the only way to accomplish this. If you never want fruit, it would be wise to consider replacing the tree. There simply is no other permanent solution.
Unthinned, harvest time
Thinned, harvest time