Published online by Cambridge University Press: 12 June 2017
In a location with cypress spurge (Euphorbia cyparissias L. ♯ EPHCY) and naturally occurring Uromyces scutellatus (Pers.) Lév. s.str., the percent of shoots deformed by this systemic rust increased from 6% in 1981 to 48% in 1982, followed by a decrease in both deformed and normal shoots in 1983 and 1984. After inoculation in 1981 of two cypress spurge crowns at a location near Zürich by teliospores of Uromyces alpestris Tranzsch., more than 80% deformed shoots were obtained in 1983 and 1984. Inoculations of cypress spurge root segments by U. scutellatus s.str. or U. alpestris in experimental plots in 1982 gave 50 to 100% infected plants, and in most cases more than 50% deformed shoots in 1984. The collection of U. alpestris studied (E-52) could be a promising candidate for mycocontrol of cypress spurge because of its pathogenicity and specificity.