Improving Wheat Yields in Ohio

Table 8: Predicted Percentage Yield Loss to Powdery Mildew Based on Varietal Susceptibility and Disease Level

Table 8. Wheat Disease Thresholds
Wheat Growth Stage	Disease	Leaf*	Disease level**
Flag lead emergence (GS8) to Boot(GS10)	Powdery Mildew	2	2 to 3 lesions
Flag leaf emergence (GS8) to Boot (GS10)	Stagonospora leaf blotch	2	1 to 2 lesions
Head emergence (GS10.1) to end of flowering (GS10.5.4)	Stagonospora leaf blotch	2	1 to 2 lesions
Head emergence (GS10.1) to end of flowering (GS10.5.4)	Leaf rust	1(flag)	5 to 10 pustules
* Leaf number counted from top leaf (flag leaf=leaf 1) down on the tiller. * Disease level based on average of 30 to 50 tillers randomly collected throughout field.