Brussels sprout growers could double their yields by growing varieties that are less susceptible to turnip yellows virus (TuYV), new research has revealed.
TuYV is transmitted by aphids and affects a wide range of brassica crops. Previous research showed that the virus could reduce cabbage yields by 16-36 per cent, depending on the variety.
Little, however, was known about the effect it had on other brassicas until the work was undertaken by the Horticultural Development Company (HDC).
The project, carried out by The University of Warwick, found that cauliflower and Brussels sprout crops in the 2010-11 season had high incidences of TuYV despite the fact that there were low levels of aphids that year.
Up to 60 per cent of cauliflower crops and 55 per cent of Brussels sprout crops were infected with the virus.
Yields of Brussels sprouts were significantly reduced, even though controlled experiments showed that TuYV caused few visible symptoms in the Brussels sprout or cauliflower plants.
This means that because the symptoms are not obvious, growers may be unaware crops are being affected.
The project also showed variation between the susceptibility of Brussels sprout varieties to TuYV.
Speedia was the least susceptible and achieved double the marketable yield of virus-infected plants of two other varieties - and almost three times the yield of another variety.
But even the highest-yielding Brussels sprout variety had its yield reduced by 30 per cent by TuYV.
Andy Richardson of the Allium & Brassica Centre said: "This groundbreaking research has shown that TuYV can have a significant effect on commercial brassica yields, despite the lack of symptoms on plants.
"Further research is underway to determine the best approach to inhibit or reduce TuYV infections."
Turnip yellows virus Future research
In future, the Horticultural Development Company will investigate the timing of turnip yellows virus infection of Brussels sprouts and winter cauliflower and the efficacy of a range of insecticidal treatments.
In the meantime, growers are able to use varieties that are less susceptible to the virus.