Flax Response to Fungicide Application for the Control of Pasmo Disease
S. Halley, Langdon Research Extension Center-North Dakota State University, Box 310 Hwy 5 E Langdon, North Dakota 58249
*Corresponding author PH: (701) 256-2582, E-mail: firstname.lastname@example.org
To determine if efficacy of fungicides Dithane, Equus, Folicur, Headline, Quadris, Ronilan, Rovral, Stratego, Tilt, and Topsin M for the control of pasmo (Septoria linicola (Speg.) Garassini) is different from untreated in �York� flax (Linum usitatissimum L.).
Flax acreage has been increasing in North Dakota to an over 700,000 acres in 2002. Disease presence increases when proximity and planting sequence between flax crops are shortened. Pasmo disease, caused by Septoria linicola, has a long standing presence in Northeast North Dakota. The Langdon Research Extension Center staff has seen average yields of flax grown for seed reduced from previous years especially during seasons when the environmental conditions are conducive to the development of the Septoria diseases.
Fungicides are being extensively evaluated for control of Septoria diseases on small grain. Evaluation of fungicides for control of flax diseases has been mostly limited to European countries and Canada. Most of these disease evaluations have been on diseases other than Pasmo. Data on control of Pasmo by fungicide is very limited and limited data exists on efficacy of new classes of fungicides on flax. No fungicides are currently labeled for foliar flax application.
MATERIALS AND METHODS
The newly released flax cultivar �York� was selected for efficacy of fungicide evaluation for control of pasmo disease in a field at the Langdon Research Extension Center in spring 2002. Plots 5 x 16 ft. were arranged in a randomized complete block design with four replicates for a research trial in a field planted for foundation seed production. Previous crop was barley. Fungicides evaluated included Penncozeb (mancozeb), Equus (chlorothalonil), Folicur (tebuconazole), Headline (pyraclostrobin), Quadris (azoxystrobin), Ronilan (vinclozolin), Rovral (iprodione), Stratego (trifloxystrobin + propiconazole), Tilt (propiconazole), and Topsin M (thiophanate-methyl).
Treatments were applied by CO2 backpack sprayer at 18 gpa with hydraulic nozzles XR8002 oriented downward from horizontal at growth stage 8, full flower, 13 July. On 1 August the height that the pasmo had progressed upward on the plant and the height the leaves had become total necrotic was recorded. Plots were harvested with a Hege plot combine 10 September and the grain sample cleaned and processed for yield. Data was analyzed with the general linear model (GLM) in SAS. Least significant differences (LSD) were used to compare means at the 5% probability level.
RESULTS AND DISCUSSION
Neither pasmo disease nor fungicide affected yield, test weight, or the progression on the plant of the pasmo. The height of the necrotic leaves on the plant was reduced by Headline compared to the untreated and the triazoles, Folicur and Tilt.
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