Ustilago trichophora is a pathogenic fungus infecting the grass of Echinochloa genus. The effect of this pathogen on the growth of Echinochloa was not yet described. Ustilago trichophora was found and described first time in Poland in 1998 on Echinochloa crus-galli specimen. Then U. trichophora was found in several places in the region of Lower Silesia in the following years. The aim of the investigation was to study the effects of Ustilago trichophora on the biometric parameters of plants as well as of seeds of Echinochloa crus-galli. The infected specimens of barnyards grass were found lower, they displayed poorer tillering and they produced a smaller number of panicles than the healthy plants. Seeds from infected bunches weight, were characterized by lower germination and energy capacity than the control ones