Leaf Disease Complex

Leaf Disease Complex is a catch-all title for several fungal diseases that affect cereals, including Septoria, Scald, Spot Blotch, Tan Spot, Speckled Blotch, and others. These are common in the County and can be found to some degree in many fields. Some of the fungi live on the straw of the plant and some are soil-borne and may persist for many years. They are more prevalent under warm and highly humid conditions.  These diseases spread easily with wind and rain and cause damage by reducing the photosynthetic area of the plant leaves, which results in yield reduction.

What To Look For

Septoria Speckled leaf blotch
Spot net blotch Scald
Tan spot Barley yellow dwarf
Spot blotch on barley


There are many tools to use in the prevention of Cereal Leaf Complex. Some of the steps you can take to reduce the impact of this group of diseases are:

  • Rotate crops with non-susceptible host plants every second year to break the cycle
  • Use cleaned seed, preferably certified
  • Seed resistant cultivars
  • Treat seed with a registered fungicide at recommended rates
  • Apply appropriate fungicide in crop at the correct stage of the diseases