Soggy breakdown on Honeycrisp fruit. Photo courtesy of Yosef Al Shoffe, Cornell

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Spot picking fruit at the optimum stage of maturity, compared to slightly immature, can reduce bitter pit, whereas soft scald and soggy breakdown can be reduced by harvesting fruit before it becomes over-mature.

The 2014 harvest season was one of the more severe years for disorders on Honeycrisp. Ben Rice, of Rice Fruit Company, calculated that 2014 packouts were reduced by an average of 17% for soggy breakdown, 8% for bitter pit and 3% due to senescent breakdown, for a total of $2.8 million in losses. Other packers reported similar percent losses, with fruit rots being an additional concern.

Reducing postharvest losses with this temperamental cultivar is a yearly challenge.

Close up photo of a honeycrisp apple with bitter pit spots — Bitter pit on Honeycrisp. Photo courtesy of Yosef Al Shoffe, Cornell University.

Closeup photo of the inside half of a ripe honeycrisp apple showing senescence — Senescent breakdown on Honeycrisp. Photo courtesy of Yosef Al Shoffe, Cornell University.

Harvesting Fruit at the Optimum Stage of Maturity

Number of Times to Spot Pick

In our commercial trials to assess optimum number of spot pickings for Honeycrisp, fruit harvested slightly immature, or 3 versus five times, had 60% more bitter pit. Fruit harvested at an overmature stage had 40% more soft scald. As a result of that research, we developed a Honeycrisp Multiple Harvest Calculator, which is a spreadsheet tool to help you assess whether increasing the number of times you harvest Honeycrisp will be cost-effective based on potential reductions in premature fruit drop and bitter pit.

Assessing which Apples are Ready to Spot Pick

A 2015 issue of Massachusetts Fruit Notes has a ground color chart that Duane Greene and Jon Clements found to be useful when harvesting Honeycrisp. The authors reported that when starch readings average about six on the Cornell starch-iodine index, you should begin spot picking Honeycrisp, selecting fruit that have a background color of light green, white or light yellow and a pink blush turning to red. This approach is similar to the one Chris Walsh has been using with his weekly maturity evaluations. Duane and Chris both evaluated the use of a Delta A meter and found color charts to be more applicable. Since color development varies from site to site, another approach is to taste-test apples of slightly varying background colors, and then give each harvest employee an apple of the optimum background color to keep close at hand for a reference point (Ines Hanrahan, Washington Tree Fruit Research Commission).

The original 1948 Ground Color for McIntosh Apples chart may be printed for field use.

color chart for MacIntosh apples — Ground color chart (originally developed for McIntosh) that Greene et al. found to be a useful indicator for spot picking Honeycrisp (Cornell Extension bulletin 750).

Harvesting Honeycrisp at Optimum Maturity also Increases Consumer Acceptance

Another important reason for harvesting Honeycrisp at the proper stage of maturity is that sensory evaluation trials on PA fruit determined that consumers can readily detect the inferiority of apples harvested immature (Baugher and Schupp, 2010). Consumers found fruit from heavily or lightly cropped trees to also be inferior in taste.

Honeycrisp apples picked at different stages of maturity - a sensory evaluation — Fruit spot-picked at three stages (left to right - slightly immature, mature, slightly overmature) for taste tests conducted by a sensory evaluation panel.

100 panelists participated in this study conducted at the Penn State Sensory Evaluation Laboratory.

Table 1. Average taste rankings for fruit harvested at three different stages of maturity based on background color. Ranking scale: 1-3, with 1 being most preferred.
Harvest Maturity (based on background color)	Taste
Slightly immature	2.3b
Optimum maturity	1.9a
Slightly over-mature	1.9a

Increasing Calcium Levels in Fruit Relative to Nitrogen, Potassium, and Magnesium

When you complete the final spray in your season-long calcium program, you should have applied a total of 9 to 14 lbs of actual calcium to your trees in order to influence both bitter pit and storage life. Virginia research comparing calcium materials confirmed that even higher levels of elemental calcium are more efficacious on Honeycrisp (Greg Peck and Alan Biggs, 2015). Rob Crassweller and Lynn Kime developed a useful online spreadsheet to help with this calculation.

Interaction with Crop Load

In our multi-year Honeycrisp research in commercial orchards, bitter pit was reduced when the level of calcium was high relative to nitrogen, potassium, and magnesium. There was an interaction with crop load, with bitter pit further reduced at moderate crop loads.

Bitter pit vs K-Ca chart — Example of the increase in bitter pit with higher levels of magnesium + potassium + nitrogen relative to calcium (from research in six commercial Honeycrisp orchards).

Apples from croploads and how it effects bitter pit — Visual appearance of fruit harvested from trees with low (left), moderate (middle), and heavy (right) crop loads. Photo courtesy of J. Schupp.

Influence of Excessive Shoot Growth

Terminal shoot length also has a strong influence on the potential development of bitter pit in storage. We have developed a predictive tool for determining whether to store Honeycrisp or to market immediately. The tool involves measuring terminal shoots along with sampling fruit three weeks prior to harvest for cortical peel tissue analysis. Details on the procedure can be found at New Tool to Assess the Potential for Bitter Pit in Honeycrisp.

Stem-Clipping to Increase Packouts

New York growers have more experience than we do with stem clipping fruit to prevent stem punctures and subsequent fruit decay. Growers and packers report a 5% reduction in decay with stem-clipping. Based on the experiences in New York along with reports from a few PA growers, we developed a Honeycrisp Stem-Clipping Calculator to help you determine if this practice is cost-effective in your operation.

Acknowledgements

Grant Support

State Horticultural Association of Pennsylvania Research Committee
Pennsylvania Department of Agriculture

Special Thanks

Christopher Watkins (Cornell University Post-Harvest Physiologist), Chris Walsh (University of Maryland Pomologist)
Tom Jarvinen, Kristy Kraft, Erin Dugan, Catherine Lara, Montserrat Fonseca Estrada, Tom Kon, Edwin Winzeler, Melanie Schupp (Penn State)
Lee Showalter, Leighton Rice, David Rice, Ben Rice (Rice Fruit Company); Ryan Hess (Hess Brothers Fruit Company)