Antibiotics are substances produced by some microorganisms that have selective toxic effect on other microorganisms. Since their discovery toxicity of antibiotics was effectively used in control of bacterial pathogens of humans and animals worldwide. Application of antibiotics in plant protection, on the first place streptomycin, started from 1950es of the last century. Soon after that, efficacy of cycloheximide against several species of phytopathogenic fungi was observed. During 70es, oxytetracycline was used for control of mollicutes (phytoplasma), and later for fastidious bacteria. However, application of antibiotics, for medical and veterinary purposes as well as for plant protection, has been related to some consequences. .Antibiotici...