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Cereals: Wheat: Tan Spot (Pyrenophora tritici-repentis)

Author: OMAFRA Staff
Creation Date: 04 July 2005
Last Reviewed: 28 July 2007
Pub 812: Field Crop Protection Guide > Chapter 5: Cereals > Wheat: Tan Spot

Excerpt from Chapter 5, Field Crop Protection Guide, Order this publication

Table of Contents

  1. Integrated Pest Management Options
  2. Related links...

Integrated Pest Management Options

Reduced tillage and cool, cloudy, humid weather promote this disease. This disease survives in crop residues. Avoid planting wheat in conservation tillage fields in which wheat was grown during the preceding 2 years.

See Appendix G for Zadok's cereal growth stages.

  Tilt 250 E Bumper 418 EC
propiconazole – Tilt 250 E, Bumper 418 EC
Active ingredient propiconazole propiconazole
Trade name Tilt 250 E Bumper 418 EC
Rate per hectare (product) 500 mL per ha 300 mL per ha
Rate per acre (product) 200 mL per ac 121 mL per ac

Comments
Ground and aerial application. Apply at early signs of disease from the beginning of stem elongation (Zadok's 29-37). If conditions favourable to disease continue, another application will be necessary. A second spray may be applied before head is half emerged (Zadok's 49-55). Can be tank-mixed with several cereal herbicides. 45 days to harvest.

mancozeb – Dithane DG, Rainshield NT
  Dithane DG Rainshield NT
Active ingredient mancozeb mancozeb
Trade name Dithane DG Rainshield NT
Rate per hectare (product) Early: 1.1 kg per ha Early: 1.1 kg per ha
Rate per acre (product) Early: 440 g per ac Early: 440 g per ac
Rate per hectare (product) Late: 2.25 kg per ha Late: 2.25 kg per ha
Rate per acre (product) Late: 900 g per ac Late: 900 g per ac

Comments
Use lower rate for applications at Zadok's 12-21 growth stage, when crop is in 3rd leaf to tillering. Higher rate for applications at Zadok's 59 growth stage when head is fully emerged but prior to flowering. No more than 2 applications/yr. 40 days to harvest. Do not graze crop or cut for hay.

pyraclostrobin – Headline EC
Active ingredient difenoconazole + metalaxyl-M
Trade name Dividend XL
Rate per hectare (product) 300-600 mL per ha
Rate per acre (product) 121-240 mL per ac

Comments
Ground or aerial. Apply only up to flag leaf fully emerged stage (Zadok's 39). Do not apply at boot stage (Zadok's 47) and beyond. Maximum 2 applications per season. 48 hr re-entry period.

tebuconazole – Folicur 432 F
Active ingredient tebuconazole
Trade name Folicur 432 F
Rate per hectare (product) 292 mL per ha
Rate per acre (product) 118 mL per ac

Comments
Ground or aerial application. Only one application per year. Apply only up to flag leaf fully emerged stage (Zadok's 39). Do not apply at boot stage (Zadok's 47) and beyond. Use non-ionic surfactant such as Agral 90 or Agsurf at 0.125% vol/vol. 36 days to harvest.

Before using Folicur for wheat leaf diseases, consider that Folicur can only be applied once per year and has been traditionally used for Fusarium control.

trifloxystrobin + propiconazole – Stratego 250 EC
Active ingredient tebuconazole
Trade name Stratego 250 EC
Rate per hectare (product) 500 mL per ha
Rate per acre (product) 200 mL per ac

Comments
Ground and aerial application. Maximum of 2 applications per year. Do not apply the second application within 14 days of the first. Apply only up to flag leaf fully emerged stage (Zadok's 39). Do not apply at boot stage (Zadok's 47) and beyond. Can be tankmixed with Buctril M in wheat. 45 days to harvest.

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