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Table 2.5-9

Table 2.5-9. Wheat Disease Thresholds.
Growth Stage Disease Indicator Leaf¹ Disease Level²
  1. Leaf to be observed for the presence of disease. The flag leaf is considered to be the first leaf, and other leaves are numbered down the plant.
  2. Disease level is based on the average of 40 tillers randomly collected from throughout the field.
Flag Leaf emergence (GS 8) to Boot (GS 10) Powdery mildew Second leaf 2 to 3 pustules
Flag Leaf emergence (GS 8) to Boot (GS 10) Stagonospora leaf blotch Second leaf 1 to 2 lesions
Flag leaf fully emerged (GS 9) to Boot (GS 10) Leaf rust Flag leaf 3 to 7 pustules