2024 Cornell Apple Storage Recommendations

Dr. Chris Watkins and Dr. Yosef Al Shoffe

Recommendations to control browning (reading the latest Fruit Quarterly on Gala storage is recommended)

Maturity is especially important for long term storage. Flesh browning risk is usually lowest when SPI is <4.0 and when I_AD values (DA meter) are above 0.4.
PGRs applied at the correct timings are critical for long term storage of Gala apples 3 weeks for ReTain and 2 weeks for Harvista based on current data). Do not store Gala without PGR treatment for more than 4 months as they are more susceptible to flesh browning.
Store Gala at 38°F (will reduce flesh browning of fruit without PGR treatment).
Postharvest 1-MCP is recommended, but can increase flesh browning of fruit that has not been treated with field PGRs, especially later harvested ones.
5% oxygen and 1% CO₂ recommended for long term storage.
2% oxygen and 1% CO₂ for standard CA, although you can use lower concentrations of oxygen without risk.

Conditioning – especially important for the North Country

Keep fruit at 50°F for 7 days and then store at 38°F.

Conditioning greatly reduces soft scald risk but does cause bitter pit to be expressed in susceptible fruit.

The use of PGRs (ReTain and Harvista) alone:

Slight benefit on firmness, and greener fruit , and slows fruit drop.
Can maintain bitter pit susceptibility because it delays fruit maturation. Therefore, PGR use is not recommended in orchard blocks that are predicted to have high bitter pit risk.
Decreases risk of soft scald development.

1-MCP alone

Maintains higher acidity.
Decreases senescent breakdown incidence, and sometimes bitter pit.
Increases leather blotch risk in bitter pit susceptible fruit treated with PGRs.
Can increase core browning.

Preventing CO₂ Injury in CA Stored Honeycrisp

If CA/DCA storage, conditioning at 50°F for one week recommended -then three options – these are not all needed – they are 3 different options:

Harvest as early as possible to minimize browning risk, especially in CA.
PGR application (2 week Harvista; 3 week ReTain) is tentatively recommended.
Store at 38°
1-MCP application is questionable for this variety – it does not always cause problems, but overall tends to enhance browning disorders. (We think that it less of an issue in short term storage, e.g. 2 months on air and 4 months in CA)
Conditioning as per Honeycrisp provides variable responses.
Low oxygen –DCA –may have promise as it helps maintain quality absent 1-MCP, but not for all disorders.
Use of DPA is worth considering for CA stored fruit because of CO2 injury risk. (CO2 injury seems less of a problem/risk for north country fruit)
Storage length is a major factor, although limited information.

Store at 38°
Best postharvest regime to date is conditioning/1-MCP/38F.
DCA is usually superior to CA following this practice (especially for core browning).

More research is needed but recommendations to date are:

Recommended storage temperature is 38°F.
1-MCP enhances internal browning.
Conditioning decreases flesh firmness in air storage and not in CA compared with continuous 38⁰F.
CA (2% O₂/ 1% CO₂) storage maintained flesh firmness and reduced flesh browning incidence compared with air storage.
DCA is recommended for long term storage, and has the additional advantage of maintaining good fruit flavor.

More research is needed but recommendations to date are:

Recommended storage temperature is 38°F.
1-MCP is not recommended as it can enhance core and flesh browning disorders.
ReTain is recommended to reduce watercore at harvest and physiological disorder development during storage.
Managing watercore is important to reduce physiological disorder development.

Harvest Timings

No information for NY-grown Ambrosia. Canadian research by Jennifer DeEll suggests:

Starch values for long term storage should be between 2.5 and 4. Starch 4-5 ok for short term, above 5 should market immediately.
I_AD readings of 0.7-0.5 for longer storage, 0.5-0.3 short term storage, below 0.3 should be marketed immediately.
Target 18-19 lbs firmness, >11% SSC.
Advanced maturity will lead to browning disorders, mealiness, and splits.

Harvista reduces internal browning. Postharvest 1-MCP reduces greasiness, improves firmness, maintains higher acidity and soluble solids. Inconsistent effects on internal browning.

Lower oxygen in storage leads to less internal browning. Very little at 0.6% and greatly reduced in 1.7% from 2.5%.
Less browning at 1% CO2 compared to 2%.
Conditioning for 1 week at 50°F also greatly reduced internal browning.
4 weeks at 38°F before 33°F decreased internal browning. Did not impact firmness, but fruit were slightly greasy and slightly less acidic.