Pre-harvest fruit drop (PFD) causes significant yield losses in 'Honeycrisp' apples. This study evaluated naphthaleneacetic acid (NAA), aminoethoxyvinylglycine (AVG), and their combined application for PFD management, assessing fruit retention and quality for two growing seasons. All treatments generally reduced PFD compared to controls, with AVG often showing the greatest reduction. However, AVG consistently impaired red fruit color development. In contrast, NAA effectively controlled PFD without negatively impacting color or firmness and improved fruit sweetness. These findings highlight that while both can reduce drop, NAA provides a better balance for 'Honeycrisp' growers by mitigating PFD while preserving or enhancing key quality attributes like color and sweetness compared to AVG.

This project evaluates a novel approach to managing pre-harvest fruit drop (PFD) and enhancing red coloration in ‘Honeycrisp’ apples by combining two plant growth regulators: aminoethoxyvinylglycine (AVG, marketed as ReTain) and 1-aminocyclopropane-1-carboxylic acid (ACC, marketed as Accede). Conducted over two seasons (2023–2024) in Virginia, the study compared six treatments—including ReTain, Accede, Motivate (ethephon), and their combinations—applied to mature ‘Honeycrisp’ trees. While ReTain effectively reduced fruit drop, it also suppressed color development. Conversely, Accede enhanced coloration but led to higher fruit drop. The combination of ReTain and Accede proved to balance these trade-offs, significantly reducing fruit drop while improving red color and maintaining desirable fruit quality traits. The findings offer a practical strategy to maximize both yield and marketability in ‘Honeycrisp’ apple production.