Septoria tritici blotch is present in Wimmera wheat crops. Growers and agronomists are urged to inspect crops for symptoms (focussing on the oldest leaves), with a view to fungicide control if warranted.

This disease was common at low levels in the Wimmera in 2016. The carry-over of inoculum on wheat stubbles, combined with recent wet conditions, has increased the potential for disease development in early sown crops this year. Given favourable conditions (frequent rain) this disease can cause losses greater than 50 per cent.

• Key management recommendations:
• Inspect wheat crops for septoria symptoms, focusing on lower, older leaves
• Where septoria is found, apply fungicide at growth stage Z31-32
• If spring is wet, consider a second fungicide application at full flag leaf (Z39) to protect the upper canopy
• Do not apply the any fungicide active to a crop more than once in a season.
• Adhere to product label recommendations.

Further information can be found at https://extensionaus.com.au/field-crop-diseases/protect-wheat-fromseptoria-tritici-this-spring/

Symptoms

Scouting of crops for septoria tritici blotch (STB) symptoms should focus on the older leaves. Look for pale grey to dark brown blotches on the leaves which contain black fruiting bodies (pycnidia), which are visible to the naked eye, within the blotches. If the black fruiting  bodies are not observed, it may be yellow leaf spot or nutritional disorders such as aluminium toxicity or zinc deficiency.

• Useful resources
• Current Victorian cereal disease guide
• Identification and Management of Field Crop Diseases in Victoria:
• Septoria tritici blotch of wheat – GRDC
• Septoria tritici – eXtensionAUS YouTube Playlist