Episode
096: Do Plant Growth Regulators Have a Place in Winegrapes with Dr. Matthew Fidelibus
- Podcast
- Vineyard Underground
- Published
- Apr 28, 2026
- Duration seconds
- 3060
- Processing state
not_requested
Actions
POST https://stenobird.com/v1/public/podcasts/vineyard-underground-6280933/episodes/096-do-plant-growth-regulators-have-a-place-in-winegrapes-with-dr-matthew-fidelibus/transcription-requests
Idempotently request low-priority transcript generation for this episode.GET https://stenobird.com/podcast/vineyard-underground-6280933/096-do-plant-growth-regulators-have-a-place-in-winegrapes-with-dr-matthew-fidelibus.md
Read the agent-friendly Markdown representation of this episode resource.
Summary
Plant growth regulators (PGRs) are powerful tools that can dramatically influence vine performance, but they also come with complexity and risk. In this episode, Fritz welcomes back Dr. Matthew W. Fidelibus of UC Davis to explore how these compounds are used across table, raisin, and wine grape production. Dr. Fidelibus explains that PGRs include both naturally occurring plant hormones and synthetic compounds that mimic hormonal effects. While they've long been foundational in table grape production, their use in winegrapes is far less common and more nuanced. The conversation highlights how sensitivity to timing, rate, and variety is critical, with even small misapplications potentially affecting fruit set, bud development, or yields across multiple seasons. Fritz and Dr. Fidelibus dig into specific compounds like gibberellic acid, abscisic acid, and ethephon, discussing how they can influence berry size, cluster architecture, color development, and ripening. They also explore emerging research on improving color in virus-affected vineyards, delaying ripening in warm climates, and even modifying aroma profiles. A key takeaway is that PGRs are not a one-size-fits-all solution. They require careful evaluation, regulatory compliance, and, ideally, small-scale trials before broader use. For growers facing challenges like poor fruit set, uneven ripening, or compact clusters, these tools may offer targeted solutions — but only when used with precision and a strong understanding of vine physiology. Listeners will walk away with a clearer understanding of both the potential and the pitfalls of incorporating PGRs into vineyard management. In this episode, you will hear: Overview of plant growth regulators and how they influence vine physiology Historical use of PGRs in table a…