Thinning efficacy of four different formulations of 6-benzyladenine on apple

This study evaluates the thinning efficacy of four different formulations of 6-benzyladenine (BA) on apple trees, i.e., MaxCel, Exilis/Exilis 100 XL, and Globaryll 100. Conducted over four years in Switzerland and Germany, the trials aimed to determine if formulation variations affect thinning performance and fruit size.
Results indicate that MaxCel exhibited equal or superior thinning efficacy compared to Exilis and Globaryll 100. In line with this finding, thinning with MaxCel led to bigger fruits in comparison with the other two formulations.
No difference in inner fruit quality (ripening, firmness, sugar and acidity) was measured between the four formulations.
The result of a foaming test indicates that the proportion of wetting agents was probably higher in MaxCel than in Globaryll 100 or Exilis/Exilis 100 XL. This difference might explain the observed variances in thinning efficacy between the tested formulations.
However, it remains unclear under which circumstances (crop load, weather conditions, cultivar, etc.) wetting agents should be added to Exilis or Globaryll 100 to ensure their efficacy.
Therefore, additional tests are needed to better understand the importance of wetting agents in fruit thinning.

EUFRIN Fruit Thinning Working Group Symposium

T.M. Kuster, K. Biegert

fruit thinning, apple, orchard, wetting agent, crop load

https://doi.org/10.17660/ActaHortic.2025.1443.7