All the plants in their natural habitats establish mutual co-existence with soil microorganisms. In the roots zone the dynamics of this process is the most significant and it affects vegetation of plants and soil conditions both directly and indirectly.

The soil penetrated by the root system (or rhyzosphere) is a habitat of different groups of microorganisms: those which decay organic substance and those which affect a plant by means of different kinds of interactions with the roots system. The latter group includes both disease-causing pathogens and some that stymulate growth of plants, provide plants with nutrients which they would not otherwise absorb and microorganisms which can protect a plant against pathogens.

For a plant, the most important form of co-existence is symbiosis with fungi (called mycorrhiza) and bacteria. The main feature of such a symbiosis is that no harmful interactions are possible, while the beneficial influence will be significant in supporting growth and protecting against pathogens, especially in conditions which make plants vulnerable to diseases.

If we observe stable and healthy eco-systems we will discover, that despite the pathogens living there, the plants are healthy. The problems begin, when the subtle equilibrium collapses and parasitic microorganisms take over in the roots zone.

As a result, a problem occures that is feared of by everyone who deals with any kind of plants production: the plants begin to fall ill. Obviously, we can use the helpful hand of chemical industry, which has been waiting for such an opportunity. However, once applied, pesticides tend to weaken the natural resistance of the environment, by eliminating both harmful and beneficial microorganisms.

Specific conditions of environment for the growth of plants are created in nursery production. The basement soil that is used bases upon high peat or on its substitutes of similar properties, like cocoa fibre, brown coal and others. These kinds of basement soil are very convenient for nursery men, but are deprived of these kinds of microorganisms, that in natural ecosystems protect the plants against pathogens.

A question should be asked: how can we use biological methods of protecting plants in conditions of nurseries? Let us try to answer this question, at least partly, and attempt to search for sensible solutions.

The solutions can be found in the nature, since had it not had them, all the plants would have become infected by parasite-based diseases. One of the methods of preventing attack is plants' immunity to diseases and their ability to defeat a pathogen.

This ability, however, is sometimes not sufficient, as (especially in intensive production in nurseries) this border can be easily broken, particularly in pathogen-friendly conditions.

In order to change this situation, it is important in intensive production to try to provide the plants with their natural allies: mycorrhizal fungi and bacterial microflora appropriate for the roots of the plants.

The microorganisms that have been mentioned can both protect the plants against pathogens and restrain their activity in soil. Defensive function of these microorganisms bases on antagonisms: antibiosis, mycolysis, nutritious and habitational competition or parasition of pathogens.

Developing biological methods of plants protection in nurseries seems to be a reasonable alternative to chemical protection: pesticides. These chemical compounds are assumed to eliminate pathogens, although they can indirectly (for example through the products of self-desintegration) restrain the activity of beneficial microflora.

Our company produces mycorrhizal inoculants of highest possible efficiency, which are isolated from habitats which require plants to be resistant to soil-based diseases. Moreover, basing upon this habitats, we prepare bacterial inoculants. We carry out initial research, but even the results of the first experiments suggest, that it be the right way to achieve healthy decorative and forest plants. A huge advantage of mycorrhizal and bacterial inoculants is the fact, that they co-exist with a plant throughout its lifetime.