Pyraclostrobin Fungicide for Reducing Losses from Pasmo Disease in Flax

S. Halley*, K.Y. Rashid, R. Horsley and K. Misek

S. Halley and K. Misek, Langdon Research Extension Center, North Dakota State Univ., Langdon, ND 58249, USA, K.Y. Rashid, Morden Research Centre,  Agriculture and Agri-Food Canada, Research Branch, Morden, Manitoba, R6M 1Y5, Canada and R. Horsley North Dakota State University, Fargo, ND 58105.

*Corresponding auth or (Scott.Halley@ndsu.edu)

ABSTRACT

            Flax (Linum usitatissimum L.) has been an important part of the farming landscape in North Dakota and the prairies of Canada for many years. Flax fits well in crop rotation with small grains because it is not susceptible to the pathogens that cause Fusarium head blight (scab). Flax also is seldom affected by the pathogens that cause white mold (Sclerotinia) in broadleaf crops such as canola, sunflower, dry bean, soybean, and several pulse crops. Flax is affected by Septoria linicola the causal agent of the pasmo disease. This pathogen infects the leaves, stems, and bolls of flax. Because of the intermittent severity of the disease, research to develop management strategies to reduce the effects of pasmo has been limited.  The Canadian cultivars Somme and CDC Bethune and the USA cultivars Carter and York were used in this study at the North Dakota State University Langdon Research Station in 2007 to assess the effects of this disease on different cultivars.  The commercial fungicide Headline (Pyraclostrobin) was applied at three treatments; one prior to flowering, one 14 days after flowering, and two sequential applications at the rate of 148 g a.i./ hectare. The cultivar Somme showed the highest level of pasmo disease in this trial.  The three fungicide treatments increased total plant dry matter (not including roots), increased seed yield, improved test weight and oil concentration of the seed, and increased the amount of fiber produced per acre.