Dr. Katie Gold and Dave Combs from Cornell University join Fritz to unpack one of the most confusing topics facing winegrape growers today: how biological fungicides truly fit into a spray program.

Katie explains how the Cornell grape pathology program has expanded rapidly, moving from strictly conventional efficacy trials into extensive work with biologicals as more of these products come out of R&D pipelines. She outlines why growers can't rely on "the next new conventional" anymore and how biologicals are becoming essential tools for sustainable disease management and resistance stewardship.

Dave brings decades of field experience and shares how his initial skepticism about biologicals shifted after seeing modern products perform on highly disease‑prone varieties in one of the toughest vineyards for powdery mildew, downy mildew, black rot, and bunch rots. Together, they walk through what "compatibility" really means and why water pH, formulation, and whether an organism is alive or dead matter far more than many growers realize.

Listeners learn why mixing biologicals and conventionals in the same tank often provides no added control (and may waste money), where negative interactions can show up, and why tightening intervals and understanding infection periods is critical when working with protectant biologicals.

In this episode, you will hear:

• Why more new products in the pipeline are biologicals rather than conventional chemistries

• How Cornell's high‑pressure pathology vineyard reveals the real-world limits and strengths of biologicals

• Why many biologicals are strictly protectants and must be applied before significant disease is present

• How tank mixing biologicals with conventionals can reduce cost-effectiveness without improving control

• Why understanding water chemistry, pH, and product formulation is now an essential spray-program strategy

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Resources:

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Episode Sponsor:

Today's episode was brought to you by Shellt Grow Tubes and Vigneron Toy Store

Thank you to Shellt Grow Tubes for sponsoring today's episode. Shellt makes the ultimate grow tubes for grape vines and orchard trees. Their grow tubes are reusable, recyclable, and designed to grow with your vineyard by clicking together for taller or wider coverage. I exclusively recommend Shellt Grow Tubes to the growers I work with. Visit https://www.shellt.us/ and order with the code UNDERGROUND to save 15% off all online orders, plus free shipping within the continental United States.

Thank you to Vigneron Toy Store for sponsoring today's episode. Vigneron Toy Store specializes in Harvesters, Sprayers, Frost Mitigation Equipment, Canopy Management Trimmers, and more. As grape growers themselves, they can expertly help you determine the best equipment for your specific vineyard needs. And, as a special offer for our podcast listeners, you can save 5% off in-stock machines by entering the promo code Underground on the contact form at vignerontoystore.com.

Episode Credits

If you like this podcast and are thinking of creating your own, consider talking to my producer, Emerald City Productions. They helped me grow and produce the podcast you are listening to right now. Find out more at https://emeraldcitypro.com. Let them know we sent you.