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 introduce a new tool to help growers expand the chemical thinning window: Accede^® Plant Growth Regulator. Accede expands the chemical thinning window for apples sized up to 15 to 20 millimeters, helping reduce 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. It fits well alongside tools like PoMaxa^® Plant Growth Regulator and MaxCel^® Plant Growth Regulator earlier in the season.

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

Neither Accede nor ethylene have maximum residue limit (MRL) concerns at harvest. While Accede helps tackle thinning larger fruitlets, it is most effective when used alongside other PGRs.

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 their acres, workforce and apple varieties.

To learn more, visit the Accede product page or contact a sales rep.

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