Biology and effectiveness of Uromyces heliotropii Sred., a potential biological control agent of Heliotropium europaeum L.

summary The rust fungus Uromyces hellotropii Sred. shows potential for the biological control in Australia of the common heliotrope ( Heliotropium europaeum L.), an annual weed of European origin. Teliospores of the pathogen remained viable when stored for one year at temperatures between −8 and 20°C, and carried infection over from one summer growing season to the next under a Mediterranean‐like climate. Both in glasshouse and field inoculation experiments, the rust rapidly killed infected plants and reduced or prevented seed production. U. heliotropii appears capable of surviving in the Mediterranean‐like climatic areas of Australia where common heliotrope is a problem weed and is sufficiently virulent to cause significant field infection.