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Title: CONTROL OF STRIPE RUST OF WINTER WHEAT WITH FOLIAR FUNGICIDES, 2004

Author
item Chen, Xianming
item Wood, David

Submitted to: Fungicide and Nematocide Tests
Publication Type: Research Notes
Publication Acceptance Date: 1/10/2005
Publication Date: 5/1/2005
Citation: Chen, X., Wood, D.A. 2005. Control of stripe rust of winter wheat with foliar fungicides, 2004. Fungicide and Nematocide Tests. 60:CF027

Interpretive Summary: A fungicide study was conducted in an experimental field with Palouse silt loam soil under natural infection of stripe rust near Pullman, WA. Urea was applied at the time of cultivation. Susceptible 'PS 279' and 'Hatton' winter wheat cultivars were seeded in rows 14 in. apart with an experimental drill planter on 22 Oct 03. A mixture of Harmony Extra, Buctril, and Agridex was applied on 29 Apr when wheat plants were at tillering stage. Ammonium sulfate was broadcast on 4 Jun when wheat plants were at booting stage. Fungicides were applied on 6 Jun at boot stage when PS 279 and 'Hatton' had 1% of stripe rust severity. Six fungicide treatments and one non-treated control were used. A second spray of Quilt plus 1% COC was done only for the first treatment with Quilt on 16 Jun at heading stage. A randomized block design was used with four replications for each treatment. Plots were individually measured at the time of harvesting, ranging from 111.8 to 115.2 sq ft. Stripe rust severity (percent of infected foliage) was assessed for each plot on 14 Jun, eight days after fungicide application at boot to heading stage; 28 Jun, 22 days after fungicide application at milk stage; and on 12 Jul, 36 days after fungicide application at soft dough stage. Yields were determined from plots harvested on 15 Aug when kernels were naturally dry. Test weight of kernels was measured for each plot. Rust, test weight, and yield data were subjected to analysis of variance and means were separated by Fishers protected LSD test.

Technical Abstract: A fungicide study was conducted in an experimental field with the Palouse silt loam soil under natural infection of stripe rust near Pullman, WA. Urea (46-0-0) was applied at 60 lb/A at the time of cultivation. Susceptible 'PS 279' and 'Hatton' winter wheat cultivars were seeded in rows of 14 in. apart at 60 lb/A with an experimental drill planter on 22 Oct 03. A mixture of 0.33 oz Harmony Extra, 0.75 pt Buctril, and 1% Agridex per A was applied on 29 Apr when wheat plants were at tillering stage. Ammonium sulfate (20-0-0-24) was broadcast at 30 lb/A on 4 Jun when wheat plants were at booting stage. Fungicides were applied as fl oz of product in 16 gal water/A on 6 Jun at boot stage when PS 279 and 'Hatton' had 1% of stripe rust severity. Spray was done between 7:30 am and 8:45 pm when the wind was between 3.9 and 6.0 mph and the temperature about 64 C. A 601C backpack sprayer from R & D Sprayers Inc. was used with a C3470 regulator and a 2.5 lb CO2 compress cylinder. The spray boom had four nozzles 19 in. apart, but three were used because of the width of the plots. The spray pressure was 18 psi. Six fungicide treatments and one non-treated as control were used. A second spray of Quilt 14 fl oz/A plus 1% COC was done only for the first treatment with Quilt at 7 fl oz/A on 16 Jun at heading stage. A randomized block design was used with four replications for each treatment. Plots were individually measured at the time of harvesting, ranging from 111.8 to 115.2 sq ft. Stripe rust severity (percent of infected foliage) was assessed for each plot on 14 Jun, eight days after fungicide application at boot to heading stage; 28 Jun, 22 days after fungicide application at milk stage; and on 12 Jul, 36 days after fungicide application at soft dough stage. Yields were determined from plots harvested on 15 Aug when kernels were naturally dry. Test weight of kernels was measured for each plot. Rust, test weight, and yield data were subjected to analysis of variance and means were separated by Fishers protected LSD test.