Mechanical Thinning of Peaches is Effective Postbloom

Abstract

<jats:p>Hand-thinning (<jats:italic>Prunus persica</jats:italic> L. Batsch) “Y”-trained peach trees at bloom and 51 days after full bloom (DAFB) was compared to mechanical fruit thinning 51 DAFB using a spiked-drum and an impact shaker. The spiked-drum shaker removed more fruit from horizontal branches than from vertical branches, yet did not selectively remove either large or small fruit. Bloom thinning by hand increased fruit size compared to postbloom thinning 51 DAFB, and both postbloom mechanical thinning techniques were as effective as postbloom hand thinning. The spiked-drum shaker may be a better thinning technique than the impact shaker because it transfers less shaking energy to the fruit, can be used in high-density plantings, and does not contact the trunk, lessening the potential for tree damage.</jats:p>

Evaluation of a New Machine for Flower and Fruit Thinning in Stone Fruits

“…The preliminary tests carried out in this study confirmed that the new thinner developed in France can be used on stone fruit both at blooming and at the green fruit stage, with minimal harm to the branches or the fruits even when thinning is performed at a more advanced fruit growth stage. Either in apricot and peach, the machine did not seem to selectively remove either large or small fruit, similar to what was found in other studies of mechanical fruit thinning [2,38,39]. However, as found in other tests with the same machine (7), the results varied largely, being affected by the species, the cultivar, the flowers and/or fruit loads, and the shoot length.…”

“…Tests were carried out on narrow-canopied orchards, more easily accessible, and hence best suited to the penetration of thinning elements such as strings or rods [2,11,22] during blooming time and on Sustainability 2018, 10, 4088 4 of 12 green fruit. The trials were carried out in March-May 2016 on two apricot and two peach commercial orchards, located in the provinces of Forlì-Cesena and Ravenna, northeast Italy.…”

“…Crop load adjustment through thinning is hence a necessary practice to minimize competition for assimilates among fruits and to produce a crop of marketable size and quality. Most peach and apricot growers worldwide manually remove excess fruit around 40-60 days after full bloom (DAFB) [2][3][4][5][6][7]. However, hand thinning is an expensive, labor-intense practice, and the skilled workforce needed to perform this operation at best is increasingly difficult to find [8].…”

“…Mechanical thinning can reduce the manual thinning requirement from 40% to 100% [8,11,14]. Over the years, a number of thinning devices, with constructively and functionally different operative systems, have been tested on peach and, to a lesser extent, on apricot [24], including hand-held devices [25], trunk shakers [12], spiked drum canopy shakers [2,8,22], frequency electrodynamic limb shakers [9,26]. String thinner devices such as the German-designed Darwin ® or similar machines operating with a rotating rope curtain [8,11,23,27,28] have been quite successfully tested on peach orchards trained to narrow canopy systems, for example, Central leader or perpendicular V, reducing the manual thinning requirement [8,23].…”

Einfluss selektiver mechanischer Fruchtbehangsregulierung auf Ethylensynthese als Stressindikator sowie Ertrag und Fruchtqualität bei Kernobst

“…Link 2002). Neben der chemischen und Handausdünnung kommt seit einigen Jahren eine interessante Alternative hinzu: die mechanische Blütenausdünnung mittels einer Ausdünnma-schine (Menzies 1980;Smith u. Galliott 1990;Glenn et al 1994;Stimmer u. Kelderer 1997;Handschack 1999;Weibel u. Walther 2003).…”