In cooperation with the Henderson County Master Pomology Program, we initiated an effort to monitor apple fruit maturity in commercial orchards in Henderson County, NC. The goal of this program is to provide timely updates regarding fruit maturity of several apple cultivars in the region. Data will be presented weekly to commercial apple growers via web-based updates to partly aid in harvest management decisions. Please note that the data presented is limited to the specific orchard block that we used for sampling. Do not assume that fruit at your location are at the same stage of maturity. To be clear, there is no substitute for regular monitoring of fruit quality parameters at your own operation.

‘Co-op 39’ (CrimsonCrisp®) marketable blush increased 1.7 fold from last week to 63% which is still low for this cultivar's criteria (Table 1, Figure 1). All other fruit quality parameters have progressed this past week to levels suitable for long term storage.

'Simmons' (Buckeye® Gala) were treated with 1 pouch of ReTain® on August 3rd to delay maturation at this orchard (Table 2, Figure 2). Fruit firmness decreased 1.1 lbs to 18.2 lbs. All other fruit quality parameters remain relatively similar to last week results due to efficacy of ReTain® in delaying fruit maturation. This will be the final week of evaluation of Gala as they were in the process of being harvested at time of sample collection.

‘Smoothee’ (Gibson Golden Delicious) were evaluated for the first time this season with a starch pattern index average of 1.8, fruit firmness of 17.1 lbs and soluble solids of 11.8%. Low starch pattern index average would suggest these apples remain immature this week despite all other fruit quality parameters being on target for harvest for long term storage (Table 3, Figure 3).

'Honeycrisp' (Royal Red Honeycrisp®) maturation excelled greatly this past week with a 4.3 lbs decrease in fruit firmness to 14.7 lbs, an 11% increase in soluble solids to 14.7% and a 1.8 fold increase in average starch pattern index to 6.1 suggesting these fruit are ready for harvest for fresh market sales (Table 4, Figure 4). Balmy evenings this past week (temperatures above 60 °F) has brought about challenges in obtaining adequate marketable blush this season with only a 1% increase in marketable blush to 10% at this sampling interval. Some will be inclined to continue wait for adequate color development, but this will be a risky proposition this year. Elevated temperatures and sporadic rainfall are forecast over the next 10 days (at least). In addition, 1 inch of precipitation this past week induced some skin cracking (Figure 5).

‘Red Delicious’ starch pattern index averaged 3.2 this week with some variability in sampling ranging from 2 to 5. Marketable blush increased 1.6 fold to 67%, firmness decreased 1.6 lbs from last week to 15.8 lbs and soluble solids remain relatively unchanged at 8.9% this week (Table 5, Figure 6). While most fruit quality parameters suggest these fruit are on target for harvest for long term storage, variability in starch level index across the sampling population and low soluble solids suggest otherwise.

If of interest, please see our previous posts for more detailed information on how to manage fruit maturity. Specifically:

• Using PGRs to Manage Apple Preharvest Drop, Fruit Maturity, and Harvest Timing
• Apple Harvest Management Considerations: Special Focus on Gala

When should I harvest?

Optimal harvest timing is dictated by multiple factors, especially the intended market. While one size does not fit all, please see this resource from Michigan State University for some general guidelines.

Acknowledgements

We are very grateful for the cooperation of Pat Lancaster and the team at Grandad's Apples for hosting this project. Thank you for your generous access to your farm and fruit! This work would not be possible without my excellent colleague, co-author, and technician, Tatiana Zuber. We sincerely appreciate the great work of the Henderson County Master Pomology Program. This dedicated team of volunteers inspired the initiation of this pilot program and is assisting with data collection. I will share more information about this group in the near future.