Mildew being spotted in winter wheat
The warm/humid conditions the UK has had of late, have predisposed some crops to disease infection.
Sexually produced ascospores are released from crop debris/stubbles of previous crops and can infect a crop with symptoms appearing after 5-7 days.
Once the weather turns cooler, or if we have significant rainfall, this will stop disease development and spread. Symptoms will then disappear as the older leaves senesce.
Unless the disease is moving onto new leaves, there is no need to treat this side of Christmas.
If a treatment is deemed necessary, then a specific mildewicide (eg triazole/fenpropimorph based product) will control the disease.
Crops should be monitored early spring for signs of re-infection, especially if we have a mild winter.