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Recommended Harvest Criteria for Commercial WA-38 Storage in 2023

Prepared in August 2023. This document is reviewed and updated on an annual basis. by Ines Hanrahan, WTFRC, Carolina Torres, WSU

(Fruit destined for fruit stand sales: refer to PVM for the Farmgate Standards.)

General harvest criteria and procedures for all fruit

  • Starch Index (1-6 scale) minimum of 2.0
    • To qualify for packing, 90% of fruit in a lot must have reached a starch clearance of 5.0. Fruit picked at 2.0 starch clearance will take an average of six weeks in RA storage to reach the required clearance. (Example: Oct. 4 pick date + 6 weeks storage = Nov 20)
    • Fruit harvested below 2.0 starch clearing will not develop good flavor.
    • Fruit harvested at or above starch clearance of 3.5 may result in lower yields and/or packouts due to increased stem bowl cracking, bird damage, and development of fruit greasiness in the orchard and/or in storage.
  • Breaking background color
  • Decay management: Stem clipping recommended, pre- or postharvest fungicide, bin and room sanitation
  • Soluble solids concentration (°Brix) equal or higher than 11
  • Firmness (in lbs.) of 23 or below
  • Days after full bloom between 165–175
  • Ethylene action or synthesis inhibitors preharvest (ReTain, Harvista, Etherol etc.): not recommended.
  • DPA: not necessary (no superficial scald risk), but drench mixes with fungicide and DPA have not shown to cause phytotoxicity to date.

Use this guide in addition to the published marketing and quality standards for the 2023 crop year. First ship date for fruit produced in the 2023 crop year: November 20, 2023.

Young orchards (2 and 3- year old trees)

  • Fruit maturity development and rate of starch clearance in storage may be more variable.
  • Excessive greasiness may appear on the fruit preharvest or in storage and is not controlled with 1-MCP.
  • Heavy cropping of 2-year old trees may stunt tree growth and/or may induce biannual bearing.

Mature orchards (4 year old trees and older)

  • Fruit maturity spread within trees should allow for one pick.

Storage and Packing

  • Tasting fruit before packing and shipping is recommended to detect off flavors.
  • Bitter taste is rare, and dissipates when fruit is held in refrigerated air (RA) after several weeks.
  Storage Duration Starch Index 1-MCP recommended Background Color Additional Recommendations
RA 4 months 2-4.5 No breaking Refrigerated Air (RA): 32-34°F, >90% relative humidity (RH)
Short CA 4 months 2-4.5 No breaking Controlled Atmosphere (CA): 33°F, 1% CO2, 2% O2
Mid CA 4-6 months 2-3.5 No breaking Controlled Atmosphere (CA): 33°F, 1% CO2, 2% O2
Long CA 6-12 months 2-3.5 Yes breaking Mature orchards only (year 4 after planting or older): 1-MCP application may reduce greasiness for fruit harvested at advanced maturity (3.5-4.5)


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