Pneumatic defoliation of apple trees for colour improvement

Bicoloured apple are quite commonly affected by a lack of red coloration, especially in the bottom part of the trees.
Different treatments, such as manual leaf removal, summer pruning, or reflective white woven mulch cloth, for example, Extenday™, have proven their potential to improve the skin colour of apples.
The objective of the present work was to examine the effect of pneumatic leave removal on skin colour improvement of the bicoloured apple ‘Nicoter’/‘Kanzi^®’ and ‘Cripps Pink’/Pink Lady^®. For this purpose, different trials with a pneumatic leave blower built by Olmi (Italy) were conducted in two commercial orchards at the Research Center Laimburg near Bozen (Italy) in autumn 2018. On ‘Nicoter’/‘Kanzi^®’, defoliation by hand and pneumatic defoliation were compared, whereas, on ‘Cripps Pink’/Pink Lady^®, three different air pressures (0.3, 0.7, and 1.0 bar) were compared.
The first results were very promising, depending on cv. and year.
Trees treated with the pneumatic leave blower reached a yield of 90.1% of first quality fruit, whereas the untreated control only reached 53.3%. This brought, in some cases, a net financial gain of 10,997€ ha^‑1. No differences in ripening and starch breakdown were observed in the trials; however, some minor effects on fruit size were detected.

XII International Symposium on Integrating Canopy, Rootstock and Environmental Physiology in Orchard Systems

C. Andergassen, D. Pichler

Malus × domestica, summer pruning, quality

https://doi.org/10.17660/ActaHortic.2022.1346.49