Study of Plant Viruses in SI White Clover Pastures

Brent Denny, botany graduate student, and Associate Professor Paul Guy of the University of Otago, New Zealand have completed a study of plant viruses in South Island (SI) white clover pastures. They note in Australasian Plant Pathology that this is the first survey of SI pastures in nearly 50 years. Canterbury, Otago and Southland make up nearly 50% of New Zealand's arable and grazing land and white clover in particular provides nourishment for livestock, fixes nitrogen for pastures and crops and provides a reliable nectar flow for the honey industry.

The researchers found that every pasture except one, was infected with one to six viruses. Virus incidence tends to increase with pasture age and there were clear correlations between some of the viruses and the use of irrigation and the switch to dairy. A previously discounted virus, Red clover necrotic mosaic virus, occurred at high incidences in some pastures. Very little is known about its impact on white clover, hence, it is a priority to assess its effects and to search for resistant germplasm.

The article is available on line at http://www.australasianplantpathologysociety.org.au/. Additional details may be obtained by emailing Paul Guy at paul.guy@botany.otago.ac.nz.