Cereals: Wheat: Septoria Leaf Spot (Septoria tritici)

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

Table of Contents

1. Description
2. Integrated Pest Management Options
   • Foliar Treatment
• propiconazole – Tilt 250 E, Bumper 418 EC,
• mancozeb – Dithane DG, Rainshield NT
• pyraclostrobin – Headline EC
• tebuconazole – Folicur 432 F
3. Related links...

Description

Septoria leaf spot attacks only leaves, whereas Stagonospora glume blotch appears on the leaves and glumes. Initial infections from Septoria leaf spot appear as small, light green-to-yellow spots between the veins of the lower leaves. These spots elongate to form irregular reddish-brown lesions. Embedded in these lesions are small, dark brown-to-black fungal bodies (pycnidia) that can be seen easily with the use of a hand lens.

Septoria leaf spot appears as small, light green-to-yellow spots that elongate to form reddish-brown lesions.

Integrated Pest Management Options

Wet, windy weather and moderate temperatures favour disease development. Destroying volunteer wheat, reducing crop residue and crop rotation also help reduce risk. Use less susceptible varieties.

See Appendix G for Zadok's cereal growth stages

Foliar Treatment

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.

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 application/yr. 40 days to harvest. Do not graze crop or cut for hay.

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. Tank-mixing with insecticide is not recommended, as this fungicide could affect insecticide efficacy.

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.

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Related links...

• Agronomy Guide for Field Crops - Publication 811
  • Septoria Leaf Spot Stagonospora (Septoria) Glume Blotch
• Appendix G: Cereal Growth Stages
• Diseases
• Cereals

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