Submitted to: Proceedings of the International Sclerotinia Workshop
Publication Type: Abstract Only
Publication Acceptance Date: March 10, 2005
Publication Date: June 12, 2005
Citation: Krupinsky, J.M., Tanaka, D.L., Merrill, S.D., Liebig, M.A., Hanson, J.D. 2005. Effect of previous crops on sclerotinia basal stalk rot of sunflower. p. 75. IN: Proc. of 13th International Sclerotinia Workshop, June 12-16, Monterey, CA, Univ. Calif. Coop. Ext., Salinas, CA. Technical Abstract: Sclerotinia sclerotiorum (Lib.) De Bary is a destructive fungal pathogen that has a wide host range causing Sclerotinia diseases on many broadleaf crops. Crop diversification has increased the risk of Sclerotinia diseases by bringing more broadleaf crops into traditional cereal-growing regions. One of the objectives of a Crop Sequence Project was to determine the effect of crop sequence on Sclerotinia diseases. An experimental crop by crop residue matrix design was used to allow the simultaneous evaluation of numerous crop sequences in the same experiment under similar weather and soil conditions. During the first year, ten crops (barley [Hordeum vulgare L.], bean [Phaseolus vulgaris L.], canola [Brassica napus L.], crambe [Crambe abyssinica Hochst. ex R.E. Fr.], flax [Linum usitatissimum L.], pea [Pisum sativum L.], safflower [Carthamus tinctorius L.], soybean [Glycine max (L.) Merr.], sunflower [Helianthus annuus L.], and wheat [Triticum aestivum L.]) were no-till seeded in a strip-block design (four replicates) into a uniform cereal residue. During the second year, the same crops were no-till seeded perpendicular to the residue strips of the previous year’s crops. Thus, a 10 X 10 matrix with 100 treatment combinations, where each crop was grown on ten crop residues, was established. In the third year, spring wheat was uniformly seeded over the previous crop matrix. In the fourth year (2002), a uniform sunflower crop was used as an indicator crop to determine the carryover of Sclerotinia within four replicates of all 100 possible crop sequence combinations. The number of sunflower plants infected with Sclerotinia basal stalk rot, yield components, and oil content was related to the crops grown in 2000. The highest level of Sclerotinia basal stalk rot, lowest yield and lowest oil content was associated with plots where crambe was grown in 2000.