Cereals: Wheat: Powdery Mildew (Erysiphe graminis f. sp. tritici)


Pub 812: Field Crop Protection Guide > Chapter 4: Cereals > Wheat: Powdery Mildew

Field Crop Protection Guide 2011-2012, Order 2011-2012 publication

Table of Contents

  1. Integrated Pest Management Options
      • triadimenol – Baytan 30
    • Foliar Treatment
      • pyraclostrobin – Headline EC
      • propiconazole – Tilt 250 E, Bumper 418 EC
      • tebuconazole – Folicur 250 EW, Folicur 432 F
      • trifloxystrobin + propiconazole – Stratego 250 EC
      • prothioconazole + tebuconazole - Prosaro 250 EC
  2. Related links...

Integrated Pest Management Options

Seed Treatment

The fungus is very susceptible to weather conditions that promote drying of the crop environment, such as hot, dry sunny weather. Management includes the use of tolerant varieties, crop rotation, tillage, and fungicides. Consult with your seed company and the Ontario Cereal Crops Committee Variety Trials Results at www.gocereals.ca for variety profiles.

See OMAFRA Publication 811, Agronomy Guide for Field Crops, for thresholds and more information

 
Active ingredient triadimenol
Trade name Baytan 30
Rate (product) 50-100 mL per 100 kg seed
Comments Use higher rate for winter wheat. Must be diluted with water prior to treatment of seed to ensure uniform coverage. Treated seed will sometimes emerge more slowly than untreated seed. Avoid late seeding of winter cereals. Do not graze or feed livestock on treated areas for 40 days after planting.

 


Foliar Treatment

Foliar fungicide applications may be necessary if disease levels will result in yield losses and/or a susceptible variety has been used. Consult with your seed company and the Ontario Cereal Crops Committee Variety Trials Results at www.gocereals.ca for variety profiles. Thresholds for fungicide applications differ, depending on the age of the crop. If 5%-10% of the lower leaves are infested early in the season, control is warranted. This may limit later infection. Later in the season, powdery mildew symptoms on the flag leaf (1% of leaf) and the second leaf (3%-5% of the leaf) require immediate attention, especially if prolonged wet, humid weather is forecast.

See Appendix J, Cereal Growth Stages, on page 136.

Active ingredient pyraclostrobin
Trade name Headline EC
Rate per hectare (product) 400-600 mL per ha
Rate per acre (product) 160-240 mL per ac
PHI* Do not apply at boot stage and beyond.
Comments Ground and aerial application. Apply only up to flag leaf fully emerged stage (Zadoks 39). Do not apply at boot stage (Zadoks 47) and beyond. Maximum 2 applications/yr. 12-hr re-entry period.

 

 
Active ingredient propiconazole
Trade name Tilt 250 E
Rate per hectare (product) 500 mL per ha
Rate per acre (product) 200 mL per ac
PHI* 45
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, apply a second spray before the head is half emerged (Zadok's 49-55). Can be tank-mixed with several cereal herbicides. Maximum 2 applications/yr.

 

 
Active ingredient propiconazole
Trade name Bumper 418 EC
Rate per hectare (product) 300 mL per ha
Rate per acre (product) 121 mL per ac
PHI* 45
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, apply a second spray before the head is half emerged (Zadok's 49-55). Can be tank-mixed with several cereal herbicides. Maximum 2 applications/yr.

 
Active ingredient tebuconazole
Trade name Folicur 250 EW
Rate per hectare (product) 500 mL per ha
Rate per acre (product) 200 mL per ac
PHI* 36
Comments

Ground and aerial application. Apply to leaf foliage at the first sign or very early stage of disease, especially if weather conditions are conducive to disease development, up to the end of the flowering stage. The use of a non-ionic surfactant (Agral 90 or Agsurf) is NOT required as it is built into the formulation. Use a minimum of 100 L/ha of water for ground application, 47 L/ha of water for aerial application. Maximum 1 appplication/yr. 12-hr re-entry period.


Before using Folicur for control of wheat leaf diseases, consider that Folicur can only be applied once per year and has been traditionally used for Fusarium control, where applications are targeted at head emergence.

 

 
Active ingredient tebuconazole
Trade name Folicur 432 F
Rate per hectare (product) 292 mL per ha
Rate per acre (product) 118 mL per ac
PHI* 36
Comments

Ground and aerial application. Apply to leaf foliage at the first sign or very early stage of disease, especially if weather conditions are conducive to disease development, up to the end of the flowering stage. Use the higher rate when weather conditions are conducive to heavy disease development. Use non-ionic surfactant such as Agral 90 or Agsurf at 0.125% vol/vol. Use a minimum of 100 L/ha of water for ground application, 47 L/ha of water for aerial application. Maximum 1 application.yr. 12-hr re-entry period.

 

Before using Folicur for control of wheat leaf diseases, consider that Folicur can only be applied once per year and has been traditionally used for Fusarium control, where applications are targeted at head emergence.

 

 
Active ingredient trifloxystrobin + propiconazole
Trade name Stratego 250 EC
Rate per hectare (product) 500 mL per ha
Rate per acre (product) 200 mL per ac
PHI* Do not apply at boot stage.
Comments

Ground and aerial application. Do not apply the second application within 14 days of the first. Apply only up to the flag leaf fully emerged stage (Zadok's 39). Do not apply at boot stage (Zadok's 47) and beyond. Can be tank-mixed with Buctril M in wheat. Maximum 2 applications/yr. 12-hr re-entry period

 

 
Active ingredient prothioconazole + tebuconazole
Trade name Prosaro 250 EC
Rate per hectare (product) 800 mL per ha
Rate per acre (product) 324 mL per ac
PHI* 36
Comments

Ground and aerial application. Use a minimum of 100 L/ha of water for ground application, 50 L/ha of water for aerial application. Maximum 1 appplication/yr. 12-hr re-entry period.

 


Related links...

 


For more information:
Toll Free: 1-877-424-1300
E-mail: ag.info.omafra@ontario.ca
Author: OMAFRA Staff
Creation Date: 2 May 2011
Last Reviewed: 16 May 2011