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Precision pruning is a good first step to adjusting crop load and producing fruit of the best size and quality. Pruning to a specified number of buds starts the fruit thinning process at the earliest possible stage.

Precision pruning is a good first step to adjusting crop load and producing fruit of the best size and quality. Pruning to a specified number of buds starts the fruit thinning process at the earliest possible stage.

PHOTO BY GERALDINE WARNER

The world doesn’t need little, green apples, and growers need to stop making them.

There has always been a penalty for small apples with poor color, and in some years, it’s worse than others.

Last year, processors needed apples, and they paid good prices for apples that wouldn’t make it on the fresh market. But in most years, processing apple prices are not strong and importers stand ready to saturate consumers with apple juice concentrate from China and Poland.

In the long run, it is not clear how the apple industry will come to balance. Consumers eat about 60 percent of their apples in processed form, so surely, apples will be needed for processing. But on the other end of the scale, consumers have shown their love for fresh, big, red apples in the prices they are willing to pay for them. Modern packing plants with high-tech sorters divide apples into a multitude of niche categories and thus extract the highest value from the best apples.

The question for growers is: Why not produce only the biggest, reddest apples?

That question was addressed by speakers at Cornell University’s Precision Apple Management Summit just as spring was arriving this year. The topic was precision crop load management.

Size matters

New York State fruit grower Rod Farrow, a speaker on the program, noted that $5 a box was not an unusual premium for apples that vary from each other by a diameter difference of a mere one-sixteenth inch.

“Achieving the optimum crop value is often very difficult for apple growers,” Cornell horticulturist Dr. Terence Robinson said.  “When crop load is reduced to a more moderate size through thinning, crop value rises dramatically,” he said. But yield is also reduced.  “Although fruit size continues to increase with crop load reduction, at some point it does not compensate for the loss in yield.

“The difference between the optimum crop load and underthinning or overthinning can sometimes be a difference of thousands of dollars per acre. More precisely managing crop load will help growers achieve the optimum crop load and maximize crop value.”

Robinson noted that some of the Pacific Northwest’s best orchardists have addressed the situation with very structured orchards and iron-handed discipline. They induce branches where they want them, tie them to wires, prune each to an exact length and spur number, assign each limb on each trellis wire the task of producing a fixed share of the tree’s apples, and they thin to that exact ­number, wire by wire and branch by branch. Their thin tree walls have no apples hidden away behind branches and leaves, so sun exposure is uniform.

Operating in an arid environment, they supply each tree with just the right amount of water and fertilizer so they can size apples very precisely. They use shade and mulches to manipulate the light.

Robinson said that eastern growers can learn from what the best western growers do, and need to adopt more disciplined practices. While it is doubtful they can find the labor to do all the branch tying, pruning, and hand thinning this totally disciplined approach requires, or the money to build those sophisticated trellises, eastern growers can impose discipline and reach quality targets.

“There are three management practices that have a large effect on crop load—pruning, chemical thinning, and hand thinning,” Robinson said. “Precision crop load management uses all three management approaches to adjust crop load.”

Precise pruning

Steve Hoying, Cornell University’s horticulturist at its Hudson Valley Lab in Highland, New York, offered precision pruning as a feasible first step to adjusting crop load and achieving higher profit levels.

It starts with setting a target—knowing how many bushels per acre to shoot for and making each tree do its exact share.  That’s easier to do than it used to be.

“Today, because of the adoption of full dwarf trees planted at densities reaching and exceeding 1,000 trees per acre, we have the ability to use pruning to better produce the crop load and fruit quality we desire,” he said. “In the past, lack of uniformity of the trees and the massive absolute number of buds on a tree made accurately counting buds impractical if not impossible to estimate potential numbers of fruit on each tree.

“Today, our ability to accurately estimate fruiting buds within the tree allows us to manage bud numbers by pruning off excess fruit buds and only keeping those needed to set an adequate crop. High tree density, smaller tree size, fewer numbers of buds per tree, and improved uniformity of trees makes it possible to more easily count a representative number of trees per variety to determine the proper bud load needed to set a full crop for each apple variety.

“By pruning to a specified bud number we can start the process of fruit ­thinning to better target the specific fruit sizes of the highest returning fruit. By reducing the number of fruit buds on the tree early through pruning, we can reduce competition among flowers and fruit, resulting in increased resources for the remaining fruit and improved fruit size and quality.”