Europe’s first winter wheat with resistance to barley yellow dwarf virus is delivering outstanding disease control even under extreme pressure this season.
Speaking at a recent RAGT Seeds open day, cereals product manager Tom Dummett said trials and experience in the field showed that RGT Wolverine was offering cost-effective, season-long protection against BYDV.
“That’s very good news for growers, said Mr Dummett. “Some 82% of the wheat crop area is at risk from BYDV. Yield losses in untreated crops average 8%, but can reach 60%”.
The withdrawal of neonicotinoid seed treatments had had a significant impact on BYDV management in recent seasons, said Mr Dummett. It left pyrethroid insecticides as the only remaining chemical option to control aphids carrying the virus.
RGT Wolverine, which will be widely available for sowing this autumn, offers protection from the day it is planted to the day it is cut. Assuming a seed rate of 175kg/ha, the resistance trait costs just £15/ha.
“That is exceptional value for money, especially when you consider that neonicotinoid seed treatments, which were widely used, had been costing farmers about £23/ha for six weeks control,” said Mr Dummett.
“This was often followed by a pyrethroid to extend protection by a week or two. Including application costs, that added a further £17/ha, taking the total to £40/ha.”
Now neonicotinoids have been withdrawn, farmers facing similar aphid pressure might need to spray pyrethroids twice, costing £34/ha – and probably more often with questionable results, he added.
“Pyrethroids only have a relative short period of activity, which means repeat applications may be needed. In addition, resistant aphids can be found in increasing numbers.”
Assuming an 8% loss on an 8t/ha crop worth £160/t, Wolverine’s genetic solution equated to a return on investment of almost £88/ha.
“It’s a no-brainer, especially when you consider it also greatly eases management, removes the need to monitor aphid populations and benefits the environment. Growers who choose RGT Wolverine really can forget about BYDV control.”
RGT Wolverine is a high yielding hard feed wheat recently promoted to the Recommended List. It contains the Bdv2 gene which confers resistance to BYDV – with trials at Ickleton in Cambridgeshire putting the trait under extreme pressure.
They were sown in early September and then inoculated with virus-laden aphids four times in the autumn and four times in the spring. Plots were assessed weekly for disease symptoms from mid-April.
The variety – and other Bdv2 pipeline varieties – shrugged off infection. But several widely grown commercial winter wheats suffered badly, with the worst affected showing severe stunting and yellowing.
“All 13 non-Bdv2 wheats in the trial are showing symptoms, from obvious multiple infection sites to stunting throughout the plot,” said Mr Dummett. “The difference between the worst-affected varieties and the Bdv2 varieties is like chalk and cheese.”
In last year’s trial, eight out of 10 popular conventional winter wheat varieties yielded between 5% and 18% less when left untreated, whereas none of the Bdv2 lines lost yield.