The experiments carried out in vitro have showed that among many oils that have been investigated some of them retarded the growth of bacterium Erwinia carotovora subsp. atroseptica (peppermint, caravay and thyme oils at cocentrations 0.25 to 1.0%, thuja oil -at concentrations 2.0 and 4.0%, juniper oil -at concentrations 0.25 and 0.5%), and Pseudomonas lachrymans (peppermint, carovay and thyme oils at concentration 1.0%, thuja oil at concentrations 3.0 and 4.0%), and Pseudomonas phaseolicola (thuja oil at concentrations 3.0 and 4.0%, juniper oil at concentrations from 0.25 to 2.0%. The efficient effect on Pythium sp. and Fusarium sulphureum was noted after the usage of peppermint, carovay, and thyme oils. In greenhouse experiments peppermint and thym oils at concentrations 0.5 and 1.0% have showed efficient influence on the growth limitation of cucumber damping off. In the field experiments dressing of cucumber seeds with thuja oil emulsion at concentration 2.0% significantly decreased the growth of angular leaf spot of cucumber seedlings.
The term "biodiversity" is nowadays one of the most often used words, both, in biological and in social sciences. However, a generally accepted definition of this term is lacking. In biological sciences the concept becomes a catchall and is mostly understood in the categories of taxonomy and systematics. The understanding is obvious and necessary and yet, very unsatisfactory. Apart from the occurrence of various taxons on an area, the important elements are also: their frequency, distribution, interactions, etc., which are most often omitted or unmeasurable. When they are all considered - in the concept at least- it seems obvious that phytopathology, dealing with diseased plants, is involved in the objects reflecting the biodiversity in a very distinct way.