Where to Find Penn State's Recommendations on Chemical Thinning Materials

Description of Plant Growth Regulators for Adjusting Crop Load of Apples.

You should also consult Apple Thinning Recommendations. We would suggest that you begin using a rate that you have utilized in the past and then evaluate the model results to fine tune or adjust that rate. Besides this model you should also evaluate your orchard conditions, including your previous crop load, tree vigor, health and whether the cultivar is naturally easier or harder to thin. When making a thinning application it is also important to leave some trees unsprayed so that you can assess the response to the treatment. If you have any questions or feedback please contact Rob Crassweller.