Polysorbates as late apple thinning agents: effects on crop load, fruit development and cluster hierarchy

This study investigates the use of polysorbates 20 (T20) and polysorbate 80 (T80), as chemical thinning agents in apple (Malus domestica) cultivation, focusing on their effects on fruit size, yield and the relationship between abscission and fruitlet hierarchy.
The experiment was carried out on ‘Gala’ apple to compare the effects of T20 and T80 with traditional thinning agents and hand thinning.
Polysorbates T20 and T80 were applied twice as 5 mL L^‑1 emulsion when the king fruits reached a diameter of 12 mm and 19 mm.
The results showed that both polysorbates were effective in reducing crop load and enhanced fruit size comparable to that obtained with ethephon.
T20 showed a slightly stronger thinning effect than T80. Both T20 and T80 maintained the natural hierarchical fruitlet abscission within the fruitlet clusters, even after a spring frost that had occurred.
This research highlights the polysorbates as potential late thinning agent and do represent a promising alternative for apple production.

EUFRIN Fruit Thinning Working Group Symposium

N. Hillmayr, A. Čebulj, J. Jakopič, M. Stopar

emulsifiers, polysorbate 20/80, fruitlet thinning, apple trees

https://doi.org/10.17660/ActaHortic.2025.1443.5