Apply a fruit elimination spray to your oak tree. The key to applying a fruit elimination spray, such as Florel, is the time of year. If you don't spray under the proper conditions, it won't work.
Wait for spring, just before the tree starts to leaf out, to apply the spray. Temperatures must be at least 65 degrees consistently during the day for best results. Spraying too early or too late in the season will render the spray ineffective.
Mix 16 ounces of the chemical in 1 gallon of water in a garden sprayer.
Spray each individual leaf bundle, using a ladder as necessary. In the first year, acorn production will be reduced but not eliminated. In following years, the fruit production will slow and then stop.