Growers and agronomists across the country are reporting yellow rust infection in varieties not normally infected with the disease, as the warm, dry weather has seen yellow rust cycling aggressively.
Agrii agronomist, Todd Jex who walks crops in Wiltshire and Dorset says: “Looking at the forecast with no rain in sight it looks like it is going to be a challenging year for yellow rust.
“We are seeing it in a bigger range of varieties than we have before with good resistance ratings, and even in crops that have had a fungicide programme that should have kept rust in check up to this point.”
In varying levels yellow rust is being seen in Graham, Extase and Theodore, says Mr Jex.
“Insitor appears to have gone bang quite spectacularly. As you would expect it is mostly affecting later planted crops, but you can find it in earlier drilled crops as well.
“Whether that means some of the mature plant resistance is kicking in a bit later, or whether there is development in races out there is yet to be determined.”
Mr Jex says colleagues in other parts of the country are reporting similar issues.
Fungicide
To keep the disease in check T2s will include a strobulurin and if the dry weather continues, T3 fungicides will include tebuconazole, says Mr Jex.
“We do not normally suffer too badly with yellow rust in this part of the country but we have had very little rain and missed all the rain some parts of the country experienced around LAMMA.
"With the temperatures as they are, yellow rust goes through its life cycle in five days. Fortunately, septoria levels are low because it has been so dry but there is some septoria lower down in the canopy so we cannot ignore it.”
Samples
UK Cereal Pathogen Virulence survey (UKCVPS) which detects and identifies cereal rusts and mildew is asking growers and agronomists to send in infected leaf samples using its freepost service. For information on how to take and send a sample view Niab’s information sheet
