Arable growers across the UK are being warned that their spring cereal crops could be at high risk from aphid-spread barley yellow dwarf virus (BYDV) infection.
Agronomy group Hutchinsons says crops could be more susceptible to winged aphid attack in the coming weeks because of late spring drilling due to poor weather in March and early April.
The infection, which is the most wide spread viral disease of cereals, affects barley and oats to a greater extent than wheat, and early infections can lead to significant yield losses.
Duncan Connabeer, technical support manager for Hutchinsons, says field reports highlight that aphids have started flying and could be spreading the costly virus.
“Last spring was perfect storm for the disease, when a huge aphid flight coincided with emergence of late-sown spring cereals. This resulted in significant BYDV symptoms in regions across the UK. This season could again play into the hands of aphids if we see numbers increase, “he says.
Aphids are more of a threat to spring barley crops when plants are young, typically up until growth stage 31, after which they become less susceptible to infection.
The AHDB and Rothamsted report that the number of aphids flying and species diversity has increased substantially in May despite the slightly wetter weather.
Although winter cereal crops have all but passed the danger period for BYDV, spring crops may still be at risk and three of the main cereal aphids – grain, bird cherry-oat and rose-grain – have been recorded in suction traps.
Initial symptoms of the infection are seen as individual plants scattered through the crop with bright yellow upper leaves.
As infection spreads, larger areas of the crop become infected, appearing as patches of bright yellow and severely stunted plants.
The disease is most damaging to plants infected in the early growth stages, with its effects often exacerbated by other stress factors, including adverse weather soil acidity and other pests and diseases.
If growers plan on applying an aphicide to crops, the message is, the earlier the better.
However, Mr Connabeer warns growers that spraying may not be effective, due to rapid crop growth and repeated aphid flights.
His advice is to instead focus on improving crop rooting and vigour through nutrition and disease control, in order to boost growth and help crops progress past their vulnerable window, mitigating the effect of yield loss from the virus.
Growers can monitor aphid risk in the coming weeks following the free online AHDB/Rothamsted alerts.