14 September 2001

Barley viruses spread but help now available

MOSAIC virus in winter barley continues to spread. But there is an increasing choice of resistant varieties to help affected growers.

Barley mild and yellow mosaic viruses (BaMMV and BaYMV) can slash yields in susceptible varieties by up to 45%, says Richard Overthrow of the Arable Research Centres.

"The virus has now been found in every county of England and most of Scotland. Growers do need to consider resistant varieties.

"There are a lot of very high yielding resistant varieties, so with the exception of where you are growing for malting there is little penalty from growing a resistant variety," says Mr Overthrow.

However, malting options are more limited, with the only realistic resister Leonie. "It did quite well in 2000, but hasnt done so well this year."

Growers should beware of using results from trials on uninfected land to help choose varieties, he warns. A better guide will come from infected sites, such as the HGCA-funded experiments run by the ARC at Hatherop, Glos.

"Some varieties may seem dated and outclassed elsewhere." Jewel, for example, has been relatively disappointing in the ARCs uninfected trials recently, he says. "But put them on an infected site and they perform very well."

&#42 Super-virus risk

The threat from a new BaYMV race remains, with only one current variety – Whisper – resistant to it. "There have been 27 incidences of race 2, often known as the resistance-breaking strain, so far in the UK – again all over the country," says Mr Overthrow. "But again it is at present still only in tennis court-sized patches at most." &#42

HGCA/ARC winter barley

mosaic virus trial yields

t/ha

Carat (R) 6.85

Siberia (R) 6.44

Angela (R) 6.43

Antonia (R) 6.26

Jewel (R) 6.22

Opal 6.20

Muscat (R) 6.11

Haka 6.06

Whisper (R) 5.96

Jackpot (R) 5.84

Pict (R) 5.77

Avenue (R) 5.72

Pearl 5.61

Fanfare 5.36

Vanessa 5.36

Vertige 5.34

Leonie (R) 5.24

Heligan 5.18

Flute 5.07

Regina 4.96

Sumo 4.60

(R) = BaMMV and BaYMV resistant.