A proven, sustainable growing approach

that’s supporting against HLB: “Probiotics”

By Paul Zorner, Ph.D.

As California’s citrus industry continues to add to the area under quarantine for HLB and the Florida market works to rebuild productivity, growers across the country are looking for natural and effective approaches that have been successfully implemented in key citrus regions. What are they finding? Almost all of the top growers in the state of Florida are using a new generation of microbial-based products or soil “probiotics” to increase nutrient uptake, improve soil health, and enhance root vigor—increasing productivity from the ground up. The results are impressive, even in citrus trees impacted by HLB. 

At the forefront of this new natural approach is Rhizolizer®, a high-potency microbial soil amendment based on long-established science and proven strains. The environmentally-friendly, easy-to-apply treatments from Locus Agricultural Solutions (Locus AG) are resulting in an average increase of 82% in dry fibrous root mass*, increased canopy density, improved trunk caliber growth in replants, larger fruit size and higher Brix, which is resulting in up to 34% more pounds solids per box, as seen by third-party processors. The improved soil, root and tree vigor have also led to increased soil carbon deposition of up to 4.4 metric tons of CO2 equivalents per acre annually—helping to position Rhizolizer users as leaders in sustainability while also improving profits through optimized grove health.  

The success has caught the attention of growers across the country, leading to treatments on more than 40,000 acres in a little over a year.   

Research shows that a healthy root microbiome is as important to crop productivity as a healthy gut microbiome is to human well-being, leading to nationwide demand for “agricultural probiotics” that enrich soil health and root vigor. Rhizolizer successfully achieves these goals and supports the ability of citrus trees to flourish and naturally tolerate biotic and abiotic stress—including the impact of HLB. Because of this, growers across the country are following Florida and beginning treatments in preparation for the threat to productivity from Asian citrus psyllid.  

The key to the effectiveness of this “probiotic” trend is the fermentation process. Rhizolizer is fermented in small batches of highly concentrated live microbes. The microbrew concept enables a rapid production method that allows for customization to address specific soils and climates. The low-use-rate treatments are then shipped refrigerated to guarantee freshness and efficacy. 

The fresh, natural approach is quickly being adopted by growers and PCAs, confirming its potential to change grove management and the future of sustainable, profitable production. 


Paul Zorner, Ph.D, is a soil health and microbial expert, professor, editor and established industry presenter. He also serves as CEO of Locus Agricultural Solutions—a science company dedicated to developing a portfolio of environmentally-friendly, “probiotic”-based products and integrated programs that optimize crop productivity. 

*Data collected over one year after consistent treatments across 10 field trials 

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