A New Tool for the Late Apple Thinning Window

Pruning, trellis systems, fertilizers and chemicals are tools that apple growers have used for ages to keep trees healthy and thriving. Growers also have a variety of chemical thinning tools along with hand thinning to help them achieve their crop load goals each season. However, labor for hand thinning continues to be a challenge and plant growth regulators (PGRs) only thin apples during a small window. Until now, PGRs were only able to be used for thinning up to 15 millimeters, but there’s a new tool to add to the program.

The Art and Science of Apple Thinning

One of the questions I get asked most from growers is “How much fruit is a thinning application actually going to take off?” Because we get it – thinning can be scary; it’s both an art and a science to create a thinning program that works specifically for each orchard and the variables each season brings. There are numerous factors that could hinder thinning plans, from unexpected frosts to labor shortages. If growers thin too much too early, it could leave less fruit that is too large. And if growers don’t thin enough, trees can experience alternate bearing, limb breakage from heavy loads and smaller, less marketable, fruit. All of this can give growers heartburn when trying to find that balance of PGR applications, hand thinning and the perfect number of fruit per tree.

When crafting a thinning program, I recommend “taking a nibble approach” starting at bloom through petal fall, continuing when fruitlets are 8 to 10 millimeters, again at 12 millimeters and often up to 15 millimeters. Because these applications start off at bloom, some growers realize they did not take off enough. Until now, when fruitlets were 15 to 20 millimeters, expensive hand thinning was the only option if additional crop load management was needed.

Introducing Accede PGR

Valent U.S.A. is excited to announce a new tool to help growers expand the chemical thinning window called Accede^® Plant Growth Regulator Liquid Concentrate. Accede expands the chemical thinning window for apples sized up to 15 to 20 millimeters, which aids in reducing the need for hand thinning at this critical stage in the season. Together, with other PGRs, Accede can be used as part of a thinning program to help growers optimize their apple crop load.

Accede is derived from a naturally occurring plant hormone, which is quickly converted into ethylene using the plant’s natural biochemical pathways. The ethylene that is generated from applying Accede stimulates fruit drop.

Neither Accede nor ethylene have any maximum residue limit (MRL) concerns come harvest. And while Accede helps tackle thinning larger fruitlets, it is most effective when used as a tool alongside other PGRs.

The following graphic demonstrates how Accede fits into the late thinning window and can be applied within a thinning program, including other PGRs like PoMaxa® Plant Growth Regulator and MaxCel® Plant Growth Regulator Solution earlier in the season.  

Using PGR tools to create a tailored thinning program is key to producing marketable fruit. Depending on the history of the orchard, growers can determine their thinning needs each season to create a plan that fits for their acres, workers and variety of apples.

To learn more, visit Valent.com/Accede.

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