Abertay researchers in clover to unearth destructive bug

Scots scientists are playing a key role in a major new research effort which could save Britain’s farmers millions of pounds a year through reductions in fertiliser and pesticide use.

Biotechnology experts at the University of Abertay Dundee, in partnership with two organisations in England, have been awarded £471,000 by the BBSRC (Biotechnology and Biological Sciences Research Council) for a three-year study into the relationship between white clover and a tiny insect.

White clover is highly valued throughout the country both for its feeding value for livestock and for its ability to ‘fix’ nitrogen in the soil – a vital nutrient for other plants.

Some 75% of grassland seed mixtures sown in the UK include white clover, yet studies have shown that it only thrives in around 20% of fields managed as pasture for cattle and sheep. Experts believe that the main culprit is a tiny weevil, less than one millimetre long, which eats the roots of the plant including the all-important nitrogen-fixing nodules.

High levels of expensive fertiliser are needed to ensure that white clover grows properly and contributes to the productivity of the pasture and the livestock which feeds upon it.

Now, Abertay biotechnologists are working with colleagues at Reading University and the Institute of Grassland and Environmental Research (IGER), to find out exactly what is going on just beneath the surface of our fields.

Researchers at Reading will be using advanced CAT scanners (computerised axial tomography) to see inside the soil without physically affecting it – the same non-invasive technology used widely in medicine for diagnosing conditions inside the body.

Experts at Abertay will then apply the latest computerised statistical techniques to produce a theoretical model of what happens inside the soil and what factors are influencing change. This can then be used to predict the outcome of changing any one of those factors through management of the field. It is hoped that the study will produce a new management model which could reduce the amount of fertiliser applied to UK grassland and comply with new, more stringent, environmental legislation in the future.

Professor John Crawford, director of SIMBIOS – the joint centre for mathematical biology established at the Universities of Abertay Dundee and Dundee – explained: “We know that this weevil, from the Sitona genus, preys on the root systems of the plant, but we don’t know how it moves around in the soil to find the roots. When you are less than a millimetre long, finding a food source several centimetres away could be difficult, but Sitona seems to manage.

“We need to find out how the weevils and their larvae do this, and what environmental factors influence their success. Then we can draw up guidelines of management practice which will help farmers reduce the impact of the weevil without using expensive and environmentally-unfriendly chemicals.”