Tergitol-TMN-6 Surfactant Is an Effective Blossom Thinner for Stone Fruits

Abstract

<jats:p>Effects of Tergitol-TMN-6 surfactant on blossom thinning (fruit set), fruit quality, and yield were studied in different cultivars of peach (<jats:italic>Prunus persica</jats:italic> [L.] Batsch) during 2003 to 2005, and in one cultivar of nectarine <jats:italic>Prunus persica</jats:italic> [L.] in one orchard and one cultivar of plum (<jats:italic>Prunus domestica</jats:italic> [L.]) in two orchards in 2004. In addition to Tergitol-TMN-6, effects of Crocker's fish oil (CFO) alone in three peach cultivars or in combination with lime sulfur in a nectarine cultivar were studied on fruit set, quality, and yield. Tergitol-TMN-6 at 5 mL·L<jats:sup>–1</jats:sup> or higher rates, applied at about 75% to 85% bloom, reduced fruit set without russeting peach fruit. Peach fruit size was often increased by Tergitol-TMN-6 treatment. Applications of Tergitol at 20 mL·L<jats:sup>–1</jats:sup> or 30 mL·L<jats:sup>–1</jats:sup> excessively thinned peaches. Tergitol-TMN-6 at all rates burned foliage, but the symptoms disappeared after a few weeks without any adverse effects on tree productivity. Tergitol-TMN-6 at 7.5 mL·L<jats:sup>–1</jats:sup> or 10 mL·L<jats:sup>–1</jats:sup>, applied either once at about 80% to 85% bloom or twice at 35% bloom and again at 80% to 85% bloom, reduced fruit set without any fruit russeting in nectarine. Tergitol-TMN-6 at 7.5 mL·L<jats:sup>–1</jats:sup> to 12.5 mL·L<jats:sup>–1</jats:sup> reduced fruit set in `Empress' plum. CFO at 30 mL·L<jats:sup>–1</jats:sup> was effective in blossom thinning of some peach cultivars. A combination of lime sulfur and CFO was not effective in blossom thinning of nectarine. Considering results from several orchards in different locations in the Pacific Northwest over 3 years, Tergitol-TMN-6 is an excellent blossom thinner for peach, nectarine, and plum at rates of 7.5 to 12.5 mL·L<jats:sup>–1</jats:sup>, sprayed at a spray volume of 1870.8 L·ha<jats:sup>–1</jats:sup> when about 75% to 85% blooms are open.</jats:p>

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

“…So far, the numerous trials to cost-effectively reduce the crop load by spraying chemicals with caustic effect proved to be inconsistent on stone fruits, with the thinning effect varying from excessive to minimal according to factors such as air temperature, humidity, stage of flower/fruit development, or training system, among others [13][14][15][16][17][18][19]. Regardless of the efficacy, a standard thinning practice based on the use of chemical thinners might have a relevant impact from a toxicity point of view.…”

Efficacy of ACC (1-aminocyclopropane-1-carboxylic acid) as a Chemical Thinner Alone or Combined with Mechanical Thinning for Japanese Plums (Prunus salacina)

“…A preferred alternative approach is using blossom thinners that burn flower parts and prevent fertilization and therefore fruit set (Southwick et al, 1996). The surfactant, Tergitol-TMN-6, significantly reduced fruit set and increased fruit size in 'Empress' plums at various rates (7.5 and 12.5 mL · L -1 ) (Fallahi et al, 2006). Tergitol-TMN-6 is effective over a wide range of phenological stages from full bloom to petal fall, which allows for a longer window of application (Wilkins et al, 2004).…”

“…Tergitol-TMN-6 is effective over a wide range of phenological stages from full bloom to petal fall, which allows for a longer window of application (Wilkins et al, 2004). The current recommendation for stone fruit is to apply Tergitol-TMN-6 at 75% to 80% full bloom at 7.5-12.5 mL · L -1 (Fallahi et al, 2006), but in South Africa, blossom thinners have not been very successful.…”

Uniconazole reduces fruit set and hand-thinning, and increases fruit size in ‘Canino’ apricot (Prunus armeniacaL.)

“…These include mechanical methods or chemical treatments (Moran and Southwick, 2000;Fallahi et al, 2006), the use of inhibitors of photosynthesis (Byers et al, 1984), or applications of gibberellin (GA 3 ) approx. 9 months before flowering (Southwick et al, 1997;Gonzales-Rossia et al, 2006;Stern and Ben-Arie, 2009).…”