Impact of a mechanical flower thinning on growth, yield, diseases and fruit quality of sweet cherries (Prunus avium L.) under organic growing conditions

Abstract

The aim of this work was to determine whether mechanical flower thinning can contribute to increasing fruit size and quality as well as preventing diseases in organic cherry production. Therefore, between 2010 and 2012, in an organically managed cherry orchard at the experimental farm of the University of Vienna, Austria, about 40% of the flowers were removed at the stage BBCH 65 with a portable electrical tool (Electroflor). In addition to the thinning effect, the impact on diseases (Monilinia spp.), yield, fruit size and quality was assessed. The thinning with Electroflor showed an increasing effect on the single fruit weight of 9.2% (mean of 3 years) combined with a lower yield per hectare of 21.1%. Also some significant changes in fruit quality characteristics including higher fruit firmness (8.7%) were found. Electroflor is an effective tool for flower thinning of cherries; its use in practice makes sense if a higher price for fruits with a larger fruit size and better quality can be achieved that compensates the yield losses by thinning.