Submitted to: Canadian Journal of Plant Pathology
Publication Type: Abstract Only
Publication Acceptance Date: 6/30/2003
Publication Date: 12/11/2003
Citation: RASHID, K.Y., SEILER, G.J. EPIDEMIOLOGY OF SCLEROTINIA HEAD ROT IN WILD SUNFLOWER. CANADIAN JOURNAL OF PLANT PATHOLOGY. 2003. V. 25. P. 433.
Technical Abstract: Sunflower head rot caused by Sclerotinia sclerotiorum (Lib.) de Bary is a destructive disease which drastically reduces seed yield and quality. Replicated field trials were conducted to investigate the epidemiology and resistance in wild sunflower species. Ten plants each from 96 accessions were artificially inoculated at early-, mid- and late-flowering stages using ascospores, mycelia, or ground millet seed infected with S. sclerotiorum. After inoculation, plants were covered for 14 days using either brown paper bags, pollination bags, plastic bags, or left uncovered. Disease incidence and severity were recorded bi-weekly until maturity. Minor infections occurred on the wild sunflower heads, but the stems were severely infected showing the typical disease symptoms. The highest disease severity resulted from ground infected millet inoculum followed by ascospores and mycelia. Plants covered with paper bags had higher levels of disease than those covered with pollination or plastic bags. The highest disease incidence (88%) was obtained from ground infected millet inoculum and a paper bag covering. Several accessions remained healthy under the various artificial inoculation methods. The genetic resistance in these accessions is under investigation.