Higher BRIX Values Means Increased 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.

Why Higher BRIX Values Means Increased Pest Resistance

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 all pests swarm up until 11 and the disappear at 12 though.

In this article, entomologist and BRIX expert Thomas M. Dykstra, Ph.D. explains that different types of insects can tolerate different BRIX ranges. When a plant’s BRIX rises above the BRIX range that type of insect can tolerate, 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 can tolerate.

• Aphid group includes aphids and scale that are the least tolerant of sugars. They prefer low BRIX values and lose interest in a plant when BRIX levels are in the 6 - 8 + range.

  
  

• Sucking insects are the next you'll see fall off. This group includes leafhoppers, stink bugs and thrips. (Yes THRIPS—a bane to a flower farmer's existence so pay attention.) These guys lose interest when plants' BRIX values are in the 7 - 9 + range.

  
  

• Chewing insects like beetles , moths, etc. lose interest in a plant when the Brix values are in the 9 - 11 + range.

  
  

• Grasshopper group includes grasshoppers (obviously), crickets, etc. These guys could be considered to have the sweetest tooth and lose interest in plants with BRIX values in the 10 - 12 + range.

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.