Warning: The information in this archived item was not confirmed with the appropriate National Plant Protection Organization and is provided solely for informational purposes. Please use this information with caution.

Subject: First North American report of Puccinia rust on sunflower
Date posted: June 04, 2002
Source: ProMed
In September 1999, Puccinia xanthii Schwein., or cocklebur rust, was observed on oilseed sunflower plants (Helianthus annuus) in North Dakota (US). This rust is globally widespread on species of Xanthium and Ambrosia, but has only been observed on oilseed sunflower in Australia and on ornamental sunflower in South Africa. In North Dakota (ND), rust infected cocklebur plants (X. strumarium) were collected several km from the affected sunflower field. However, P. xanthii has not been detected in any surveyed ND sunflower field since 1999, agreeing with the observation that oilseed sunflower is much less susceptible to P. xanthii than Xanthium spp.