Penn State Extension announced on May 19 the final Pennsylvania Tree Fruit Phenology Report for the 2026 season. The organization said that further critical updates will be shared through its Fruit Times news and alert system.
This report is important for growers as it summarizes current conditions, management recommendations, and upcoming events in Pennsylvania’s tree fruit industry. Penn State Extension delivers science-based education to promote agriculture, ensure a safe food supply and responsible resource management, according to the official website.
The report outlines that temperatures in Pennsylvania are expected to start warm this week before cooling down midweek with increased chances of rain. Many growers recently applied thinning chemicals during optimal weather conditions last Saturday; effects from these applications should become visible by mid- or late-week. In Adams County, primary set fruitlets now exceed 20-25mm depending on variety, and remaining crop load adjustments will likely require hand thinning soon.
In central Pennsylvania orchards with little primary set, secondary bloom did not compensate as hoped. “Fruit set from these secondary flowers remained poor (Table 1), and the hot weather experienced over the past week accelerated fruitlet drop from these positions,” the report said. It added that early drop of weaker lateral bud fruitlets helps resolve crop load uncertainty sooner rather than later.
For Honeycrisp apples—especially those on G.11 or G.41 rootstocks—a low crop load increases bitter pit risk due to changes in calcium partitioning within plants. The report cited research showing successive auxin (NAA) sprays at intervals after full bloom can help maintain xylem function and reduce bitter pit incidence by supporting calcium delivery throughout the season.
The extension also emphasized proactive irrigation during hot days above 85–90°F while advising reduced watering starting in June to avoid excessive shoot growth that could dilute calcium concentration in fruits.
Growing degree day accumulations were provided for Adams, Berks, and Centre counties using data from local weather stations between January and May of this year.
Penn State Extension supported community well-being by addressing problems and fostering innovation for individuals and businesses; it extended services statewide via local offices and digital tools; collaborated with government, industry, and nongovernment organizations; provided workshops, online courses, consultations on topics like farming or pest control; all while focusing educational programming on agriculture, nutrition and environmental stewardship according to the official website.
Looking ahead, details about an upcoming public roundtable hosted by the Pennsylvania Department of Agriculture remain pending but will be announced through multiple channels including Penn State alerts.
