Higher Plant Brix for Lower Insect Problems? with Dr. Tom Dykstra

The Whole Farm Podcast

In this episode of The Whole Farm Podcast, presented by CHONEX, we welcome back Dr. Tom Dykstra for Part 2 of our conversation on plant health, Brix, and insect resistance.

Dr. Dykstra walks through his leaf Brix insect chart and explains how different Brix levels relate to plant health, insect feeding behavior, disease pressure, and crop resilience. Dr. Dykstra explains why he focuses on leaf Brix rather than fruit, stem, or root Brix when evaluating plant health. He breaks down what different Brix ranges can indicate, from plants that may require “force feeding,” to plants beginning to develop stronger secondary metabolites, to healthier plants that are better able to resist insects and disease.

He also discusses how different insect groups—aphids, sucking insects, chewing insects, and grasshoppers—tend to correspond with different plant health levels. The conversation then turns practical, with a focus on how farmers can use this information in the field.

Dr. Dykstra emphasizes the importance of sugar, carbon, and micronutrients in supporting microbial activity, improving plant function, and increasing Brix levels. He explains why sugar applications are often the first step when dealing with very low-Brix plants, and why micronutrient availability can become a limiting factor in photosynthesis and plant performance.

We also discuss how Brix testing can fit alongside traditional scouting practices. Dr. Dykstra shares that farmers may see measurable plant response within 24 to 72 hours after applying the right nutrition, and that Brix can help show whether a treatment is moving the plant in the right direction. The episode explores how this approach compares to conventional insecticide responses, especially when growers are trying to stop insect feeding before crop damage worsens. Later in the episode, Dr. Dykstra connects Brix and soil health to drought resilience, explaining how carbon, sugar, organic matter, and microbial activity all influence water retention in the rhizosphere. He also shares his perspective on nitrogen management, including why excess salt-based nitrogen applications may lower Brix and how free-living nitrogen-fixing bacteria can support crops when soil biology is functioning well.

This episode is a practical follow-up for growers, agronomists, and soil health professionals who want to better understand how plant health measurements can inform pest management, nutrient decisions, and whole-farm resilience.