Darlington and Stockton Times - 18th June 2015
OILSEED rape crops in Yorkshire are reported to have infection rates as high as 72 per cent for Turnip yellow virus (TuYV).
Dr John Walsh of Warwick University led the research for Limagrain UK and gave his findings at Cereals 2015.
“Results from across the country are showing worryingly high levels of infection with some hotspots showing levels as high as 72 per cent infection,” he said.
“Generally, these hotspots are where you would expect due to the large areas of oilseed rape grown, however the levels of infection are much higher than they have been for the last few seasons with Yorkshire and East Anglia at around 72 per cent infection, and some surprises such as 64 per cent infection in Somerset.”
TuYV is considered the most important, yet least understood, viral disease in oilseed rape.
However, Alan Dewar, of Dewar Crop Protection, believes these high incidences are due to high numbers of aphids flying last autumn when many oilseed rape crops were drilled early.
He said: “It was also the first autumn without neonicotinoid seed treatments and, whilst there are insecticides available there are some issues around timing and duration of control, as well as developing resistance to pyrethroids and primicarb, which can severely impede fully effective control.”
Studies by Warwick University have confirmed that the earlier the infection the greater the yield loss.
Dr Vasilis Gegas, Limagrain’s senior oilseed rape breeder, warned that there could be some fairly significant yield losses this year.
“The difficulty with TuYV is that it is difficult to identify and often yield losses will be attributed to other factors,” he said.
” However in trials with high levels of virus, resistant varieties could out yield non-resistant varieties by 10-15 per cent, demonstrating the value of resistance in protecting yield.”
Mr Dewar said: “This means that variety choice will be more critical than ever and will require a change in mind set where resistance and agronomics play an increasingly crucial role in order to protect yield.”
Amalie is the only commercially available oilseed rape variety with resistance to TuYV on the market.
A conventional OSR variety, it offers a gross output similar to the widely grown DK Cabernet variety, and can yield up to 10 per cent more than non-resistant varieties in the presence of TuYV infections.