High BRIX Values and Pest Resistance

As we’ve already beat to death in our BRIX blog series, BRIX measures how well a plant is photosynthesizing. The higher the BRIX level, the healthier the plant—and this health doesn’t just show up in thick, dark glossy leaves, sweeter-tasting fruit, more fragrant blooms (too bad dahlias don't have a scent), resilience to weather mishaps and even better resistance to disease. It also shows up in the plant’s ability to resist—or maybe better said, repel—pest pressure. Simply put, insects prefer to suck, chew, or munch on unhealthy plants because they’re easier to digest. The healthier a plant is, the less desirable—and less palatable—it becomes to pests.

As we’ve discussed, the “magic” number for seeing the all benefits high BRIX levels can bring is 12+. That doesn’t mean that pests swarm up until 11 and vanish at 12 though.

In this article, entomologist and BRIX expert Thomas M. Dykstra, Ph.D. explains that different insects are drawn to plants at specific BRIX ranges. When a plant’s BRIX rises above the BRIX range that type of insect likes, they lose interest and move on to less healthy and more palatable plants.

Insect Groups & Their Preferred BRIX Levels

Dr. Dykstra has found four main groups of insects and the BRIX ranges they prefer.

• Aphid group includes aphids and scale that are the least tolerant of sugars. They prefer low BRIX values of 5 and below.

• Sucking insects includes leafhoppers, stink bugs and thrips. (Yes THRIPS—a bane to a flower farmer's existence so pay attention.) These guys lose interest in plants with BRIX values between 7 and 9.

• Chewing insects like beetles , moths, etc. lose interest in a plant when the Brix value falls between 9 and 11.

• Grasshopper group includes grasshoppers (obviously), crickets, etc. These guys could be considered to have the sweetest tooth and are interested in plants with BRIX values between 10 and 12. Above or below that range and they're out.

Dr. Dykstra goes on to say when you get familiar with these insect groups and their preferred BRIX ranges, you can accurately "guess" a plant's BRIX level by seeing what kind of pests hang around it. I can personally vouch for that! I introduced my parents to BRIX and was showing them how to take measurements so they could start tracking it. As I took a closer look at their dahlias, I noticed some aphids on a few of the plants. Sure enough, their BRIX reading came in at a 5.

So...Now What?

And for a regenerative farmer who doesn’t have quick-fix chemicals to lean on when pest pressure mounts, knowing that higher BRIX can make my dahlias less “edible” and less desirable to pests is priceless. So...we'll continue to run head-long down this road of prioritizing soil health and microbe support. You can see the current

ways we're doing this in our "Soil Health and Microbes: The Foundation of BRIX" post.

I’ll keep sharing updates, new discoveries, experiments, and even data in the coming seasons, so you can learn from both our triumphs and our mistakes.

And don't forget that we’d love to hear from you! Please take a moment to share your experiences in the comments so we can keep learning together.