Asparagus rust

P. asparagi attacks all aboveground plant parts. Symptoms appear as red or brown elongated spots on asparagus stems, branches, leaves and spears. The discoloration is due to dusty fungus spores produced in small pustules; a reddish colour predominates at first but becomes blackish later in the season. The discoloration can make entire plants look like they have ripened prematurely with subsequent weakening of roots and crowns. Severe rust infections stunt or kill young asparagus shoots, causing foliage to fall prematurely and increased water loss, reduced plant vigour and premature death (Waterston, 1965; Elmer et al., 1996; Babadoost, 1999; Vakalounakis and Pavlou, 1999).

Rust decreases the quantity and quality of edible spears. In addition, disease weakens the plants, predisposing them to infection by other diseases, such as wilts and root rots (Babadoost, 1999).