The ability to control soil-borne pathogens is mainly conditioned by the restrictions to the use of synthetic pesticides, and genetic resistance is hindered by new pathogen races or by only a partial expression of the resistance. Allelopathy, the antimicrobial activity of plant extracts, is a promising option against crop pathogens. Extracts from some Lycium spp. possess biological and therapeutic properties. Individual methanolic extracts from L. europaeum were each evaluated in vitro against Verticillium dahliae (Vd), Sclerotinia sclerotiorum (Ss) and Harpophora maydis (Hm). The mycelial growth of the three fungi was significantly reduced by all the extracts at doses of 10 and 30 µl mL-1. The sporulation of Hm was almost completely inhibited but that of Vd was stimulated by some of the extracts. Sclerotia of Ss were formed in a smaller number, their total weight increasing at high extract doses. In greenhouse, and as early as 6 weeks after inoculation, Hm caused significant decreases of weights in both roots and aboveground parts of maize. Decreased weights were also associated with the methanol aqueous solution control treatment. The detrimental effect of Hm on root weights was counteracted by one of the leaf extracts. Eleven phenolic compounds were separated in the extracts. The hydroxycinnamic acid family, including chlorogenic acid as a major compound, represented more than 50 % of the total content in all the samples. Rutin was the most abundant flavonoid. Bioactive L. europaeum extracts, after development into final products and combined with other tools, have the potential to protect crops in the field.