EPISODE · Apr 7, 2026 · 55 MIN
Episode 162: Dips, Sprays, & Phytotoxicity: Mastering Oils in Cannabis Cultivation with Julie Graesch
from Cannabis Cultivation and Science Podcast · host Tad Hussey.
Why can't you just use canola oil from your kitchen to kill spider mites? If you’ve ever wondered about the true science behind oil-based pesticides, this episode is a deep dive into the physics and chemistry of plant protection. Tad and Julie Graesch explore why oils remain one of the most effective tools for managing resistant pest populations like two-spotted spider mites and thrips. In this episode, we cover: Physical Modes of Action: How oils kill through suffocation and desiccation, and why pests can’t develop resistance to being physically smothered. Mineral vs. Essential Oils: The functional differences between horticultural mineral oils (like SuffOil-X) and 25B essential oils (like Epishield). The Power of Formulation: Why inert ingredients, surfactants, and molecular weight are just as important as the active ingredients for preventing phytotoxicity. Dipping vs. Spraying: The high-stakes world of plant dips and how to target specific life stages—including the elusive thrips egg. Tank Mixing & Compatibility: Best practices for combining oils with microbials like Beauveria bassiana to create a synergistic knockdown effect. Whether you are a small-scale hobbyist or a large-scale commercial cultivator, understanding how to master oils will help you maintain a cleaner garden with fewer chemical interventions. You can order Bioworks products through KiS Organics, just reach out if you have any questions. About the Guest: Julie Graesch is the Technical Services Manager for BioWorks. With over 18 years of experience as a biological scientist, Julie has worked in laboratory, greenhouse, and field research, specializing in integrated pest management (IPM) for the horticulture industry. Hosted by Simplecast, an AdsWizz company. See pcm.adswizz.com for information about our collection and use of personal data for advertising.
What this episode covers
In this episode, Tad Hussey welcomes back Julie Graesch, Technical Services Manager at BioWorks, to demystify one of the most common yet misunderstood tools in a grower’s IPM toolkit: Horticultural and Essential Oils. While many growers reach for oils to "suffocate" pests, the science behind their efficacy—and the risks of phytotoxicity—is far more complex. Julie breaks down the critical differences between EPA-registered mineral oils and 25B essential oil products, explaining how different modes of action like desiccation, paralysis, and behavioral repellency work together to bypass pest resistance. They also dive into the "why" behind professional formulations, discussing how emulsifiers and surfactants make the difference between a clean kill and a scorched crop.
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Episode 162: Dips, Sprays, & Phytotoxicity: Mastering Oils in Cannabis Cultivation with Julie Graesch
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