Picture: Stephen Williams inspecting BYDV infection
Caption: Syngenta field trialist Stephen Williams inspects this season's early BYDV damage in winter barley
Barley Yellow Dwarf Virus symptoms are hitting cereal crops up to three weeks earlier than normal in parts of the UK. That is despite low numbers of aphid vectors that carry the disease being reported last autumn.
"Although confined to untreated plots in our trials, what's surprising is just how aggressively the classic BYDV yellowing and stunting symptoms have appeared," says Syngenta field trialist Stephen Williams who is researching the new insecticide seed treatment Thiamethoxam.
"The mild winter is the key culprit because aphids weren't killed off by frosts. As a result the infection period continued much longer."
Although too late to rescue BYDV damage this season, Mr Williams insists growers must take note of how bad uncontrolled symptoms have become from such low aphid numbers when planning cereal drilling next autumn.
"A good insecticide seed treatment not only guards against early aphid attack, but also buys time if follow-up aphicide sprays are unavoidably delayed.
"As well as giving a 0.9 t/ha yield increase over imidacloprid based treatments in previous BYDV trial plots, Syngenta trials show Thiamethoxam has also delivered a 40% reduction in grain damage from slugs."
