2025 Pennsylvania Tree Fruit Maturity Report - October 13

Introduction

Welcome to Pennsylvania State Extension's weekly tree fruit maturity report! Maturity metrics for key varieties will be tracked across the state throughout the 2025 season. Informed harvest timing is critical for fruit quality, particularly for apples in mid- to long-term storage. Balancing sugar accumulation, color development, starch clearing, and pressure loss is difficult to manage. These reports serve to provide insight and help inform management decisions.

These reports are collated on a "landing page" (termed a "campaign" by Penn State) that can be bookmarked for future reference. Every report issued will appear on the campaign page, often prior to being sent out via email. Missed a report last week or need to review a recommendation? Reports for the entire season will be collected there for quick access.

Informed harvest timing is critical for fruit quality, particularly for apples in mid- to long-term storage. Balancing sugar accumulation, color development, starch clearing, and pressure loss is difficult to manage. These reports serve to provide insight and help inform management decisions.

Weather and Color Development

Cool weather continues in Southeast Pennsylvania this week with highs ranging from 64 to 76°F and lows ranging from 39 to 54°F. With only one rain event predicted on Sunday, we are returning to drier weather conditions this week. Keep an eye out for calyx end cracking from the recent rains, especially in thinner skinned varieties and overmature fruit.

Storage Options

Storing fruit properly is critical for maintaining fruit quality and integrity. Recommendations specific to different cultivars change and get more specific as researchers continue to study the impact of different storage conditions on fruit quality. Below are recent recommendations on apple storage.

• Presentations available from 2024 Controlled Atmospheric Storage Clinic
  • Above includes research on Ambrosia, EverCrisp® Gala, and Honeycrisp storage practices and physiological disorders.
• Fruit Disorders- Practices to Manage Storage Disorders in Honeycrisp

Adams County

Maturity samples were collected from two orchards in Biglerville (Adams County). Please adjust harvest decisions based on the specific conditions at your site.

¹ The one orchard with EverCrisp® still on the trees conducted a first-pick pass on them. The data represents the fruit available for a second picking.

² Fruit was collected from a single orchard in Adams County.

³ The aggregate data is the mean (average) of the two sampled strains.

EverCrisp®

EverCrisp® is mature in Adams County. The pressure is still quite high (21.7 lb), but is currently dropping. The starch index value (5.4) and very high sugar levels (16.1 °Bx) indicate that this variety is one to watch this week. However, the advanced starch levels should be watched closely. Of note, this high sugar content can make the fruit more prone to watercore, which was observed in the samples collected for this report. Please see this resource from MSUE on watercore. Consider watercore when making long-term storage decisions.

Nittany

Nittany has been holding firm since last week and is still nicely mature. Despite the high fruit firmness (19.0 lb), the starch index value (3.5) and sugar content (14.5 °Bx) indicate that this variety is ready for harvest this week. It should be watched closely in the next two weeks.

Pink Lady®

Two strains of Pink Lady®—one from each of the participating orchards—were harvested: the original "Cripps Pink" and "Lady in Red". These are reported aggregately and separately in the table above. Commentary is based on the aggregate, as there are several strains of Pink Lady® in various stages of development in Adams County orchards.

Despite the high pressure of the Pink Lady® cultivars this week (23.2 lb), they are quickly progressing. With a starch index value of 4.5 and a sugar content of 14.9 °Bx, they should be monitored closely, especially if additional color development is desired. Particular care should be taken for their starch levels if long-term storage is the production goal.

Berks County

Due to a building closure for a county holiday on Monday, fruit could not be analyzed. Unfortunately, there is no report for the Berks region this week.

Centre County

Maturity samples were collected from one orchard in Centre County; please adjust harvest decisions based on specific local site conditions.

EverCrisp®

EverCrisp® is moving into its maturity window in Centre County. Both the firmness (18.1 lb) and starch index values (4.1) have progressed in the last week. This, paired with the lightening background color, indicates that this variety is now mature. The high sugar level (14.8 °Bx) comes through in the excellent taste of this fruit. Of note, this high sugar content can make the fruit more prone to water core. Please see this resource from MSUE on water core. Consider water core when making long-term storage decisions.

Pink Lady® (Cripps Pink cv.)

While the Pink Lady® sample this week looks to be comparatively less mature than last week, it is mature in Centre County. Fruit firmness (20.6 lb) still needs to further develop for this variety to be optimally mature.

Conducting Maturity Tests at Home

While this article series points to trends across the state, it provides data from only three counties. Because of this, conducting tests locally can provide specific information to best guide harvest timing. This article on determining fruit maturity and optimal harvest dates has information on the hows and whys behind maturity metrics. Please consider reading the article before interpreting these reports, as it can better explain why each metric is used. It also describes the tools used, some of which are available for modest prices (such as a basic penetrometer), which can support your own maturity testing methods.

Iodine Starch Indexing

Iodine testing and starch index scales are a user-friendly approach to collecting maturity information. The starch iodine index values in these reports are estimated using an excellent new resource from Michigan State University. A PDF version of the booklet is available for free, and printed copies may be available from a local Extension office. Please be aware that the (largely inert) chemicals used in the staining process are no longer available over the counter and require authorization from the federal government to purchase. For information on how to acquire them, contact the authors.

Controlling Harvest Timing

Stop-drop materials are widely used to delay fruit ripening. There are a number of stop-drop products available for use in Pennsylvania. These chemicals, including ReTain®, Harvista™, and NAA products, all interfere with ethylene production in apples. Controlling the harvest window can be beneficial for U-Pick operations by expanding the accessibility of highly desirable varieties into the peak fall season. Stop-drops can also be implemented to manage the workflow of orchard crews to ensure that more apples are harvested at peak ripeness. Additionally, delaying harvest can allow for longer exposure to better weather for color development.

Reference Data

The data reported above may be compared against the following previously published information. Consulting these tables may be useful when making decisions about optimal storage time based on your storage requirements.

Conclusions

Commercial fruit growers, please note: apple maturity conditions need to be monitored at a local level within one's own orchard. Before chemical products are applied, be sure to comply with current federal, state, and local usage regulations and examine the product label. Product information can be easily obtained online from CDMS.

This series of updates is made possible by a State Horticultural Association of Pennsylvania (SHAP) Extension Grant (Pennsylvania Apple Maturity Program). The authors thank SHAP for the funding and thank the growers participating in these updates and allowing access to their orchards to sample fruit.