They are a type of association that is established between certain soil fungi and the roots of most cultivated plants. It is a mutualistic symbiotic relationship, since both fungi and the plants that host them benefit.

Which plants form mycorrhiza?

Depending on the type of fungus and the host plant, this will be the type of mycorrhiza that is formed. The name that each type of association receives, in most cases, is defined by the characteristic that makes it peculiar.

Most of the horticultural, ornamental and fruit plants form endomycorrhizae (the fungus is established inside the root). Others, like a large part of forest plants (birch, fir, poplar, hazelnut, chestnut, poplar, oak, beech, pine, oak, among others), form ectomycorrhiza. Some ornamental and fruit species such as azalea, carnation, camellia, heather, rhododendron, and bilberry form ericoid mycorrhizae. In addition to these, there are other types of minor mycorrhizal associations in agriculture and landscaping.

One of the most significant exceptions is plants that are not capable of associating with any mycorrhizal fungus, among which horticultural species such as cabbage, broccoli, cauliflower, spinach, radish, turnip and mustard stand out.


Why are they important to plants and soil?

Among the most important effects of mycorrhizae are:

  • Improve soil structure by forming stable aggregates that slow erosion
  • Increase the absorption surface of the root, increasing its capacity of capturing nutrients and water
  • Greater tolerance to water, saline and pathogen stress
  • Increased transplant survival
  • Stimulation of the production of secondary metabolites related to defenses


Can they be removed with phytosanitary chemical treatments?

Not all fungicidal active ingredients are harmful, although there are many which, by eliminating the pathogen, eliminate competing beneficial organisms. Please, consult our technical service for information about active materials compatible with mycorrhiza. 

In the mycorrhizas gamma, we focus our research on new ways to apply mycorrhiza to plant/soil system as well as the characterization and incorporation of kindred substances and microorganisms (new isolates of mycorrhizal fungi and rhizobacteria).


The word PGPR, in English, Plant Growth Promoting Rhizobacteria, is used worldwide to define a type of bacteria in the rhizosphere that promotes plant growth.

Which plants benefit from the action of these microorganisms?

All plants that grow in soils where rhizobacteria exist or where they have been artificially inoculated, are likely to benefit from their action.

Why are they important to plants and soil?

  • Produce plant growth regulators (phytohormones, B vitamins)
  • Fix atmospheric nitrogen.
  • Solubilize Phosphorus by stimulating phosphatase activity and organic acids.
  • They unlock nutrients in the soil, increasing their availability.
  • They produce metabolites that provide protection to the plant.
  • They stimulate the general microbial activity of the rhizosphere and help to rebalance and enrich the biological fertility of the soil.

Bioera has implemented a series of research programs in search of comprehensive microbial solutions to resolve nutritional imbalances and promote growth and endogenous defenses of plants. We are also working on the characterization and incorporation of related substances and microorganisms (new microbial species and mycorrhizal-forming fungi).


Many plant species have a wide biochemical potential that must be evaluated through research.

With the formulation of specific botanical extracts, biostimulant substances are provided that can induce or enhance certain plant processes and even increase the production and protection of crops.

Bioera has several open research projects for the development of new products and combinations of organic compounds and plant extracts.

Microbial compounds:

All Bioera products containing arbuscular mycorrhizal fungi incorporate bacteria to enhance root inoculation and ensure a high rate of mycorrhization. These two types of microorganisms do not compete with each other and exhibit a synergistic effect when applied together.

95% of horticultural crops benefit from the use of arbuscular mycorrhizae. There are some families, such as Brassicaceae (broccoli, turnip, rapeseed, or arugula), and some weeds which do not form mycorrhizal associations. Additionaly, Ericaceae (i.e. blueberry, heather) associates with another type of mycorrhizae (ericoid mycorrhizae).

The case of bacteria is different from that of mycorrhizae, and they can be applied to all crops. They do not have specificity for crops.

Indeed. They are eco-friendly and do not incorporate genetically modified organisms. Most products in the Microbial Range are certified for use in organic agriculture. Some also have certification for use in biodynamic agriculture.

There has been a taxonomic reclassification, and names have changed. Previously, species were classified based on the shape of their spores, but currently, it’s done through molecular tests. For example, the famous ‘glomus intraradices’ is now called ‘rhizophagus irregularis.’

Some active ingredients with fungicidal activity, especially when applied directly to the soil, can modify mycorrhizal activity. At Bioera, we have compatibility tables that can be consulted. Additionally, very high concentrations of phosphorus in the soil could inhibit mycorrhizal activity.

Yes. Mycorrhizae form a network of hyphae, or ‘fungal roots,’ that absorb water and nutrients and supply them to the plant root. For every 1 centimeter of root, we can have up to 30 meters of hyphae. This allows for the extraction of water and nutrients from soil pores that roots cannot reach, providing an extra supply of water.

Some PGP bacteria compete for space and nutrients with many phytopathogenic fungi, providing protection against fungal diseases. Mycorrhizae also assist by acting as a barrier and covering much of the root surface, as well as compensating for root loss with extra absorption surface.

Mycorrhizal fungi increase the absorption surface, expanding the volume of soil explored by the plant. In addition, bacteria have the ability to solubilize inorganic P, mobilize K, chelate Fe, fix atmospheric N, etc., making more nutrients available to the plant. The combined use of mycorrhizae and PGP bacteria is a very useful tool for reducing the need for fertilizers.

Products from the Bioradis Range can be applied. These products contain arbuscular mycorrhizae, which confer greater tolerance to heavy metal toxicity in crops through mechanisms such as phytostabilization (immobilization of heavy metals in the rhizosphere) or phytoextraction (accumulation of metals in leaves).

Since 2017, the Spanish Fertilizer Law (RD 999/20217 amending RD 506/2013) includes products with microorganisms. Therefore, they can be used just like traditional fertilizers. In most European countries, there is mutual recognition of the Spanish Fertilizer Law, allowing for their sale.

These are two different reproduction technologies. Bioera has chosen in vivo technology. This allows for the reproduction of a greater number of mycorrhizal species in a more natural way, as it is done in the field rather than in a laboratory or bioreactors. It results in products with a longer shelf life and, most importantly, provides a product that has higher success guarantees in the final crop. These products are more infective, resistant, and have a greater capacity to colonize new roots.

The optimum time to inoculate with mycorrhizae is at the beginning of a plant’s life, either during germination or at the transplanting stage. Mycorrhizae colonize new roots and absorbing root hairs. It’s easier to reach these with mycorrhizae when a plant is young. For adult plants, inoculation should occur during a phenological stage when the plant is producing new roots, as these will be the most susceptible to mycorrhization.

When bacteria are applied, they have an immediate effect; they achieve much of their work within 2 hours. They adapt, colonize, and multiply rapidly. In contrast, mycorrhizal association takes a few days. In herbaceous plants, this association occurs more quickly, typically taking around 10 to 20 days, while in woody species, it may take 30 to 60 days.

Firstly, it provides great adaptability. In some crops or environments, one species may thrive more easily than another, thus increasing the chances of success. For example, in soils with different pH levels or organic matter content. Secondly, each species may have different functions, especially in bacteria, providing products with diverse beneficial functions such as stimulation, protection, nutrient solubilization, and tolerance to water stress.

A good way to quantify the concentration of mycorrhizae is through the spore content, which are the ‘seeds’ of the mycorrhizal fungus. For bacteria, it is measured in colony-forming units (cfu), which are viable units or propagules capable of forming a colony.

Spores are a type of propagule. Other types of propagules include mycelium, roots infected with mycorrhizae, or vesicles. On average, it can be considered that 1/3 of the propagules in a mycorrhizal inoculum are spores. Therefore, a product with 200 propagules/g contains approximately 65 spores/g.

Spores are resistance structures that fungi form to ensure their propagation, making them highly resistant to heat and low humidity. This is not the case with mycelium, for example, which has a very short lifespan. Therefore, measuring in spores guarantees a concentration of inoculum that will remain viable for a long period of time.

At Bioera, we measure the richness of a mycorrhizal product in spores/g. The dosage depends on the volume of roots and the method of application. As a general rule, 200 to 1000 spores/plant are applied, depending on the root volume and the efficiency of application.

The shelf life of a well-preserved microbial product is typically 3 to 5 years. Depending on the regulations of each country, the product labeling may indicate an expiration date of 1 to 2 years from the date of packaging.

Fertilizers and deficiency correctors:

Micronutrients are nutrients that plants require in smaller quantities, but this does not mean they are less important. They perform vital functions for growth, and any deficiency undoubtedly leads to a loss of productivity. The main micronutrients include iron, manganese, boron, copper, zinc, and molybdenum.

Complexed nutrients are absorbed by the plant more rapidly as they are immediately available. This availability is especially evident in foliar applications. When applying a complexed nutrient via irrigation, it is advisable to split the applications or carry them out during phenological stages with high rates of nutrient uptake (e.g., calcium during fruit setting) to avoid losses. A chelated nutrient is more stable in the soil in the long term, but its absorption is more challenging.

Amino acids have rapid absorption, translocation, and metabolism capabilities. Therefore, when applied together with micronutrients, they facilitate their absorption.


A biostimulant is a naturally derived substance that enhances nutrient use efficiency, provides plants with greater stress tolerance, or increases the quantity and quality of crops. Examples of biostimulants include seaweed extracts, amino acids, and plant growth-promoting microorganisms (PGPM).

An amino acid profile is a schematic representation of the amino acid composition of a fertilizer. Each amino acid elicits a different response in plants. For example, Glutamic Acid promotes sprouting and leaf formation, flowering, and fruit setting. On the other hand, Arginine has rooting activity and induces the phytohormone auxin. And so on, sequentially.

Alginic acid is a structural polysaccharide naturally present in the cell walls of brown algae, serving as a quality parameter for a seaweed-based product.


The European Regulation on Plant Protection Products categorizes Basic Substances as “substances with plant protection properties that have traditionally been used in agriculture and are available on the market with other primary uses, such as food.”

Examples include horsetail extracts, soy lecithin, nettle, or chitosan, which have fungicidal, insecticidal, or defense elicitor effects.

The basic substances we work with at Bioera, at recommended doses, are environmentally friendly, safe for beneficial fauna, and do not cause phytotoxicity. This means they can be used in the presence of pollinators or natural predators, and they can also be mixed with other products or fertilizers without risk of toxicity to plants.

Organic compounds and humic complexes:

The addition of organic matter brings multiple benefits. Soil that is rich in organic matter has a greater capacity to supply nutrients to plants, retain water more effectively, and foster the growth of beneficial soil microorganisms.

Many beneficial microorganisms require the carbon present in organic matter to live and reproduce. Soil that is rich in organic matter, or the addition of carbon sources along with the application of microorganisms, facilitates their establishment and allows them to thrive longer in the soil.

Total humic extract is the sum of humic acids and fulvic acids. Humic acids have a higher molecular weight than fulvic acids, greater cation exchange capacity, and greater water retention capacity. On the other hand, humic acids have a slower but more lasting effect on soil structure and plants, whereas fulvic acids have a faster effect on plants but are less persistent.

Supplementary Fertilizers:

Copper gluconate is formed by the combination of copper with gluconic acid, making it more easily assimilated and an effective way to administer this mineral. It can be used as a copper deficiency corrector or as a sanitization measure since incorporating copper into the plant’s metabolism reduces fungal and bacterial diseases.

Carboxylic acids significantly increase nutrient uptake and plant osmotic pressure, enhancing water flow and nutrient transport. Nutrients complexed with carboxylic acids are absorbed more rapidly, especially in foliar applications.

Foliar nutrition offers several advantages as it delivers nutrients directly to the foliage, bypassing the soil, thus acting much faster and avoiding nutrient losses through leaching or immobilization in the soil. Therefore, foliar nutrition allows for rapid correction or prevention of nutritional deficiencies. However, the amounts a plant can take up foliarly are lower than root uptake, meaning there is a risk of applying either too small a dose that fails to correct the deficiency or an overdose that can burn the leaves and impact production. Generally, plants should be fertilized via the roots, and foliar nutrition should be used to correct deficiencies or apply a nutrient supplement at a specific phenological stage with high demand.