Skip to main content
ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Sunflower and Plant Biology Research » Research » Publications at this Location » Publication #140012
Title: FIRST REPORT OF ALBUGO TRAGOPOGONIS ON CULTIVATED SUNFLOWER IN NORTH AMERICA

Author
item GULYA JR, THOMAS
item VIRANYI, F - GODOLLO UNIV., HUNGARY
item APPEL, J - KANSAS DEPT. OF AGRIC.
item JARDINE, D - KANSAS STATE UNIV.
item SCHWARTZ, H - COLORADO STATE UNIV.
item MEYER, R - CO ST. UNIV. EXT. SER. S

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/31/2002
Publication Date: 5/1/2002
Citation: Gulya Jr, T.J., Viranyi, F., Appel, J., Jardine, D., Schwartz, H.F., Meyer, R. 2002. First report of Albugo tragopogonis on cultivated sunflower in North America. Plant Disease. 86:559.

Interpretive Summary: Since sunflower is an indigenous plant to the United States, all known sunflower diseases pre-exist in the United States on wild sunflower species. The one exception to that statement is the fungal disease called white rust, caused by Albugo tragopogonis. This disease is considered very serious in several countries, namely Argentina and South Africa, where is causes both leaf spots and stem lesions, the latter which may also lead to lodging. In the early 1990s white rust was observed in one county in western Kansas, and in subsequent years it spread to several KS counties as well as into adjacent eastern Colorado. By the late 1990s, however, white rust could no longer be found. The disease has not been observed in the major sunflower production area of North and South Dakota.

Technical Abstract: White rust, caused by Albugo tragopogonis (Pers.) S. F. Gray, was observed on a few plants of both oilseed and confection sunflowers (Helianthus annuus L.) in northwestern Kansas (Cheyenne county) in 1992. The disease was observed again from 1993 to1995 in nine counties of western Kansas, with incidence per field ranging up to 35%. White rust was found only on late planted fields in 1996 and 1997, and not found at all from 1998 to 2001. White rust was also observed on cultivated and wild sunflower (Helianthus annuus L.) in eastern Colorado (Kit Carson and Yuma counties) during the period 1994 to 1997, but absent from 1998 to 2001. Leaf pustules on both cultivated and wild sunflowers were similar in appearance. On the upper side of leaves, pustules were convex and chlorotic; concave, and dull white on the leaf underside. Pustules on cultivated sunflower were generally limited to 3 to 6 leaves in the middle of the plant and affected 10 to 40% of the leaf area. Sporangial dimensions fell within the reported dimensions of A. tragopogonis (1). In 1997 water-soaked lesions, 1-2 cm in length containing Albugo oospores were observed on the lower to middle portions of stems of cultivated sunflower in western Kansas and adjacent Colorado. Stem lesions were observed much less frequently than foliar lesions, and only in 1997. No Albugo sporangia were observed in stem lesions, nor were any other fungi isolated from these lesions. This is the first report of white rust occurring on cultivated sunflower in any production area of North America; the disease has not been observed in the major U.S. sunflower production area of North Dakota, South Dakota or Minnesota. Foliar white rust lesions generally have little economic impact on sunflower, but the presence of Albugo stem lesions is significant, because stem lesions have been documented to lead to lodging (2). Lodging due to Albugo was not been observed in either Kansas or Colorado. White rust has previously only been reported on wild Helianthus annuus in Wisconsin, and on perennial Helianthus spp. in Missouri and Illinois (3).