Soybeans: Asian Soybean Rust (Phakopsora pachyrhizi)


Pub 812: Field Crop Protection Guide > Pub 812: Soybeans > Asian Soybean Rust

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

Table of Contents

  1. Integrated Pest Management Options
    • Foliar Treatment
      • pyraclostrobin – Headline EC
      • azoxystrobin – Quadris
      • propiconazole – Tilt 250 E
      • azoxystrobin + propiconazole – Quilt
      • prothioconazole - Proline 480 SC
      • tebuconazole - Folicur 250 EW, Folicur 432 F
      • trifloxystrobin + propiconazole - Stratego 250 EC
  2. Related links...

Integrated Pest Management Options

Foliar Treatment

Asian soybean rust is an invasive fungal disease. Scouting and early detection are critical to managing this disease. The early stages of the disease can be confused with other common foliar diseases such as septoria brown spot, bacterial pustule, downy mildew, frog-eye leaf spot and bacterial blight.

Numerous factors such as crop stage (R1-R6), yield potential, disease risk or presence are critical components of the fungicide decision process. Strobilurin fungicides such as Headline or Quadris are protective products that stop spore germination and penetration into the soybean leaf. The strobilurins have no effect on the fungus once inside the leaf. Since the strobilurin group of fungicides have no curative activity, do not make solo applications of a strobilurin if any rust is present. The triazole fungicides such as Tilt and Folicur have varying protective abilities and are usually considered "early post-infection" fungicides. The post-infection or curative abilities are limited, and the fungicides may not perform well if 5%-10% disease is present in the lower crop canopy. Combination products containing both a strobulurin and triazole fungicide such as Quilt have preventative (pre-infection) and curative (post-infection) properties.

Long periods of leaf wetness are needed for spore germination, as well as temperatures between 15°C and 30°C and a high relative humidity. Yield loss is very likely once rust can be found in the mid-crop canopy. For these reasons, scouting, fungicide selection, timing and application are critical to successful management of soybean rust.

For further information on scouting techniques, sentinel plots, thresholds, management options and emergency use registrations, see OMAFRA Publication 811, Agronomy Guide for Field Crops, as well as the Grain Farmers of Ontario website at www.gfo.ca.

 
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* 21
Comments Ground and aerial application. Classified as a strobilurin fungicide; use this product in a preventative fungicide program (pre-infection). See label for resistance management strategy. Maximum 2 applications/yr.

 

 
Active ingredient azoxystrobin
Trade name Quadris
Rate per hectare (product) 500 mL per ha
Rate per acre (product) 200 mL per ac
PHI* 15
Comments Ground and aerial application. Classified as a strobilurin fungicide; use this product in a preventative fungicide program (pre-infection). See label for resistance management strategy. Maximum of 2 applications/yr. Re-entry possible once residues have dried.

 
Active ingredient propiconazole
Trade name Tilt 250 E
Rate per hectare (product) 500-750 mL per ha
Rate per acre (product) 200-300 mL per ac
PHI* 30
Comments Ground and aerial application. First application should be made at the first sign of disease, followed by a second application 14 days after the first application if environmental conditions are favourable for disease development. Good spray coverage and canopy penetration are important for best results. See label for resistance management strategy. Maximum 2 applications/yr.

 

 
Active ingredient azoxystrobin + propiconazole
Trade name Quilt
Rate per hectare (product) 1.0-1.5 L per ha
Rate per acre (product) 400-600 mL per ac
PHI* 30
Comments Ground and aerial application. First application should be made at the first sign of disease, followed by a second application 14 days after the first application if environmental conditions are favourable for disease development. Good spray coverage and canopy penetration are important for best results. See label for resistance management strategy. Maximum 2 applications/yr.

 

 
Active ingredient prothioconazole
Trade name Proline 480 SC
Rate per hectare (product) 210 mL per ha
Rate per acre (product) 85 mL per ac
PHI* 20
Comments Ground application only. Apply when first symptoms of disease can be found or the risk of infection is imminent. Maximum 1 application/yr. 24-hr re-entry period.

 

 
Active ingredient tebuconazole
Trade name Folicur 250 EW
Rate per hectare (product) 375-500 mL per ha
Rate per acre (product) 152-200 mL per ac
PHI* 20
Comments Ground and aerial application. Apply when first symptoms of disease can be found or the risk of infection is imminent. Use the higher rate when disease pressure is severe. Use a minimum of 100 L/ha water for ground application, 47 L of water for aerial application. The use of non-ionic surfactant (Agral 90 or Agsurf) is NOT required as it is built into the formulation. Maximum 1 application/yr. 12-hr re-entry period.

 

 
Active ingredient tebuconazole
Trade name Folicur 432 F
Rate per hectare (product) 220-292 mL per ha
Rate per acre (product) 90-118 mL per ac
PHI* 20
Comments Ground and aerial application. Apply when first symptoms of disease can be found or the risk of infection is imminent. Use the higher rate when disease pressure is severe. Use a minimum of 100 L/ha water for ground application, 47 L of water for aerial application. Always use a non-ionic surfactant such as Agral 90 or Agsurf at 0.125% vol/vol. Maximum 1 application/yr. 12-hr re-entry period.

 

 
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* 20
Comments Ground and aerial application. Begin applications preventatively from early flowering (R1) to complete pod fill (R5) when rish of rust infection is high. Use 100-200 L/ha of water for ground application, 50 L/ha for aerial application. Maximum 2 applications/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: 12 May 2011