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What is Mycorrhizal Fungi?

Mycorrhiza directly translates as "fungus-root," which refers to the beneficial partnership between the roots of a host plant and a fungus. These beneficial fungi colonize plant roots and become a true extension of the root system. Mycorrhizal fungi are very efficient at mining and absorbing nutrients and water compared to plant roots. Over the past several hundred million years, symbiotic relationships have developed between beneficial mycorrhizal fungi and more than 95% of plants.

The key component of the symbiotic relationship is the plant's capacity to produce carbohydrates through photosynthesis and share some of these sugars with the mycorrhizae in exchange for nutrients and water that are otherwise inaccessible. It is a truly symbiotic partnership between the two species that are sharing resources. The plant is necessary for the mycorrhizal fungi to exist, and the fungus helps the plant function better by supplying the plant roots with basic growing needs and protection against environmental stressors.

What is Mykos mycorrhizae_ It's a beneficial fungus that helps increase nutrient and moist

Benefits of Mycorrhizal Fungi

Mycorrhizal fungi are capable of performing many duties that ultimately benefit the host plant in many ways. The most well-known benefit mycorrhizae perform is increasing the plant's establishment by increasing access to nutrients and water. Not only does mycorrhiza increase access to food and water, but they are also experts at combating natural stressors and diseases. The fungal strands embedded in the surface of the roots can act as a barrier, deterring harmful pathogens from accessing the roots. These same fungal strands hold onto moisture very well, allowing the roots to access the water in times of drought and excess heat.

  • Greater efficiency in the uptake of water and nutrients

  • Mycorrhizal biomass promotes the storage of water and nutrients

  • Increases plant establishments and survival rates of seedlings, cuttings, and transplants

  • Increases nutrient availability, especially Phosphorus

  • Promotes more vigorous plant growth

  • Significantly increases crop quality and yields

  • Increases plant and root system development

  • Increases tolerance to high salt soils and fertilizers

  • Increases fruiting and flowering sites

  • Enhances protections again soil-borne pathogens

  • Reduces transplant shock

  • Reduces drought stress

  • Reduces fertilizer and water needs

  • Increases microbial activity and nutrient cycling

  • Improves soil structure and quality with the Glomalin naturally produces by mycorrhizae

Symbiotic Partnership

Spores, fragments of colonized plant roots, and hyphae (fungal body) are the three primary inoculum sources that mycorrhizal fungi use to colonize plant roots. Propagules are the standard unit of measurement mentioned in the majority of commercial and retail mycorrhizal products.

These propagules must be present in the soil/substrate and near to growing roots of a plant in order for the mycorrhizal fungi to colonize the roots. The plant root tips release signals into the soil, alerting the mycorrhizal fungi to colonize the roots and begin the symbiosis process. Once a plant root system is colonized, mycorrhizae are capable of producing a wider fungal network of new spores/hyphae and living in symbiosis with the life of that plant. 

Arbuscular mycorrhizal fungi propagules can be mixed into the ground before or during planting or sprinkled on a porous substrate and watered in. Mycorrhiza is best applied directly on the rootball's exterior surface before transplanting or placed in the transplant hole.

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Endo-, Ecto-, and Ericoid Mycorrhizal Fungi

Mycorrhizal fungi can be found in varieties of species that all associate with a specific set of plant families. Mycorrhizal fungi are commercially available in three common forms: Ectomycorrhizae, Endomycorrhizae, and Ericoid mycorrhizae.

Ecto-Mycorrhizal Fungi:
A form of mycorrhizae that associates with most conifers as well as some hardwoods such as oaks. Ectomycorrhizae does not penetrate the root cell walls but wraps around the cells to exchange nutrients and carbohydrates. The use of commercially available ectomycorrhizae is only necessary under certain conditions such as the introduction of a host plant into an area that does not have any other ecto hosts in close proximity. 

Endo-Mycorrhizal Fungi:
Also known as vesicular-arbuscular mycorrhizae (VAM) and arbuscular mycorrhizal fungi (AMF). This organism forms associated with the greater majority of terrestrial plants and commercially produced plants. Endomycorrhizae penetrates the root cell walls and forms arbuscules inside the cells of the roots for a direct exchange of nutrients.

Ericoid Mycorrhizae:
More commonly associated with wetland or bog plants such as blueberries, cranberries, gaultheria, heathers, rhododendrons, and azaleas. Ericoid mycorrhizae only grow on the outer surface of the host plant's roots and do not mine areas of the soil in manners similar to ecto or endo mycorrhizae.

In-Vivo Vs. In-Vitro Mycorrhizal Fungi

There are two ways to manufacture commercial mycorrhizal fungi propagules, In-Vivo and In-vitro. In-vivo mycorrhizae are grown in a host plant and in soil substrate, while in-vitro-grown mycorrhizae are grown in a laboratory setting using artificial media and genetically modified roots.


There are several reasons why in-vivo mycorrhizae may outperform in-vitro mycorrhizae when applied to crops:

  1. Adaptation to the environment: In-vivo mycorrhizae are exposed to the same environmental conditions as the host plant, which allows the biology to adapt to the local soil and climate. This can make them more effective at colonizing the roots of the host plant and providing benefits such as improved nutrient and water uptake. In contrast, in-vitro mycorrhizae may not be as well adapted to the local environment, which can limit their effectiveness.

  2. Greater diversity of fungi: In-vivo mycorrhizae are likely to be exposed to a greater diversity of fungi and other microorganisms in the soil, which can enhance their ability to form beneficial relationships with host plants. In-vitro mycorrhizae may be limited in terms of the diversity of fungi that they are exposed to, which could limit their effectiveness.

  3. Greater vigor and viability: In-vivo mycorrhizae may have greater vigor and viability compared to in-vitro mycorrhizae, which can make them more effective at colonizing the roots of host plants and providing benefits. In-vitro mycorrhizae may be more vulnerable to stress and may have a lower rate of survival when applied to crops.


Overall, in-vivo mycorrhizae may be more effective at colonizing the roots and providing benefits such as improved nutrient and water uptake due to their adaptation to the local environment, greater diversity of fungi, and greater vigor and viability.

RTI's In-Vivo Grown Mycorrhizal Fungi

RTI has established a unique process for growing and cultivating mycorrhizal fungi. Mycorrhizal fungi grown "in-vivo" promotes stronger biological genetics for quicker adaptation to soil and weather conditions. RTI produces over 6 species of arbuscular, endo-mycorrhizal fungi at our 13-acre facility in Gilroy, CA.


Every batch of mycorrhizal fungi is quality control tested and certified with the highest standards. Our goal is to provide our customers with the highest quality mycorrhizal inoculant available in any market. 

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More questions or looking for more information regarding RTI's line of mycorrhizal inoculants, please feel free to contact us directly at
1-800-784-4769 or by email
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