BYDV-resistant wheats beat conventional varieties

Winter wheat varieties resistant to a key disease have yielded around 10t/ha in an insecticide-free trial – outperforming some popular conventional varieties.

Agronomy company ProCam tested winter wheat varieties resistant to barley yellow dwarf virus (BYDV).The result strengthens the commercial case for varieties genetic protection after the virus cut yields in unprotected wheat by up to 3t/ha last autumn.

The trial recorded infection consistently below 10% among resistant varieties. Rates in non-resistant wheats ranged from more than 30% to almost 50%. ProCam said growers should combine variety choice with later drilling, green-bridge control and targeted insecticides as another high-risk season approaches.

“The yield responses of the varieties tested were quite dramatic,” said ProCam head of technical development Rob Adamson. “In the presence of the BYDV virus, the resistant varieties outperformed some of the most popular Recommended List varieties – including Champion, Extase, Skyfall, Bamford and Solitaire.”

Timing

Early drilled cereals face the greatest threat, particularly crops emerging in September and the first half of October. Historical data suggests risk falls significantly after mid-October, although warm conditions could keep later crops exposed.

Following the UK’s hottest summer on record, ProCam sees no guarantee that winter temperatures will suppress aphid populations. Growers should “delay drilling until as late as possible”, said Mr Adamson. Green bridges also carry infection between cropping cycles, he added.

Wingless aphids can move the virus from volunteer cereals and grass weeds into emerging crops. ProCam recommends destroying those plants and leaving an ideal five-week gap before sowing. Crops drilled into green cover face the highest risk.

Genetics

Variety selection can change the financial outcome. ProCam tested 10 winter wheat varieties and found RGT Goldfinch, Griffin, Gorgon and Guardsman outperformed standard non-resistant choices. In the insecticide-free trial, RGT Gorgon yielded just under 10t/ha, while RGT Guardsman delivered just over 10t/ha.

ProCam said tolerance and resistance traits in wheat varieties such as RGT Goldfinch and hybrid barley SY Kestrel gave farms another defence. The Recommended List has historically excluded data from plots infected with BYDV during trials, so headline yield potential may not reflect performance under virus pressure.

“With the latest and greatest varieties stealing the Recommend List’s headlines thanks to their higher yield potential in ‘ideal’ conditions, the promise they deliver doesn’t always translate into field performance,” said Mr Adamson.

Spraying

Growers in known hotspots are advised to assess varieties against local risk, rather than simply choosing the highest-yielding entry. Such decisions could protect output while reducing reliance on spray programmes.

ProCam also backed the AHDB’s new BYDV decision support tool. It can identify periods when crops face the next aphid influx and help time applications.

Where treatment is justified, Mr Adamson suggested Gocha, which contains 25 g/L esfenvalerate. ProCam said it was less harmful than other pyrethroids to beneficial insects such as ladybirds, which prey naturally on aphids.

Growers should use plant protection products safely, read the label and consult product information before application.