Root Disease - Prevention is Key

Root Disease - Prevention is Key

Every day plant roots are in the midst of a battle. The underground warriors being fungi and bacteria, compete with each other for food and space and ultimately determine the health of plants and their roots. The majority of soil-dwelling bacteria and fungi are harmless to plant growth. Some are beneficial species essential in breaking down large molecules into smaller ones that plant roots can take up. A few of the soil-dwelling microbes actually cause disease. These pathogens are known commonly by such scientific names as Pythium spp., Fusarium spp, Rhizoctonia spp., and Phytophthora spp. to name a few. A small number of soil microbes have displayed unique characteristics with regard to controlling, eliminating and out-competing the pathogens in the root zone. Some soil microbes lightly suppress pathogens while others sustainably prevent and control the root rotting pathogens. A select few of these special microbes consistently show such excellent disease controlling properties that they become registered as biofungicides. Trichoderma harzianum strain T-22 is an example of a very special warrior with the ability to control and eliminate disease pathogens in the root zone. T-22 can be found in the registered biofungicide RootShield®. Growers can defend their plant roots from disease with soil biofungicides — biological warfare at its finest!

Curative chemistries exist to treat or suppress a root disease until a crop is harvested. These chemicals can be effective and have for years but they are not silver bullets. Their mode of action (MOA) can be conducive to pathogens developing resistance. Many growers proactively use registered biofungicides like RootShield to prevent resistance. It is the unique modes of action in RootShield that makes it so effective.

So how does RootShield work?

Exclusion. RootShield grows in the media near plant roots or directly on the roots shielding them from pathogens. The soil biofungicide grows in and dominates the same area a pathogen wants to occupy and physically blocks or excludes it.

Competition. RootShield can remove and feed upon simple organic and inorganic compounds released from roots as part of their waste removal system. These root exudates and soil organic matter also attract pathogens.

Parasitism and predation. As a biofungicide, RootShield can attack and eat root-rotting pathogens feeding directly upon them for their own nutrition. They physically attach to these pathogens and release enzymes that dissolve the cell walls eliminating them for extended periods of time.

Nutrient availability. Nutrients must be in a reduced form to make them available for absorption by a plant’s root system. RootShield releases reducing agents and chelating agents that make nutrients more available and absorbable to a root allowing for more complete utilization of the fertilizer being applied.

ISR (Induced Systemic Resistance). In some cases but not always seen, certain soil biofungicides can trigger ISR in plants. Very specific strains of Trichoderma, Bacillus and other microorganism species, have been shown to “turn on” specific mechanisms in a plant’s root system that naturally cause the plant to defend itself from the inside. This MOA is still not well understood or predictable but is a hot topic for researchers around the world. ISR triggered by specific biopesticide strains certainly contributes to their overall efficacy.

Preventing damage from root rots begins with a good defense. Programs using conventional, IPM, sustainable and organic methods of growing should all use RootShield early as a preventative not as a curative when it is too late. Providing early protection against root diseases is a major component to producing a successful crop.

RootShield facts:

  • Effective at preventing diseases caused by Pythium, Fusarium and Rhizoctonia spp.
  • Compatible with many chemical fungicides.
  • Tolerant of wide temperature and pH ranges.
  • Long shelf life when stored at room temperature or lower.
  • Approved for use in organic programs.
  • Three readily available formulations make application to seeds, plant material and media easy and economical.
  • Zero-hour restricted-entry and pre-harvest interval.


RootShield contains a living microbe that can successfully prevent many types of root diseases under diverse environmental conditions on a wide range of plants using multiple mechanisms of control. Applying the proper soil biofungicide for an identified root pathogen early before the pathogen gets a foot-hold in the plant can make the difference in performance and the need to use chemicals.

Safety for people, safety for plants and safety for the environment are becoming more of a concern in the edible and ornamental plant growing world. RootShield offers this level of safety. Identifying problems early and preventing further spread make-up the backbone of an effective biologically based program. Soil biofungicides can and do work.

Back to blog