Dissemination of rhizomania by soil, beet seeds and stable manure

Abstract

Po/ymyxa betae, the vector of beet necrotic yellow vein virus (BNYVV), (the causal agent of rhizomania of sugar-beet), forms cystosores which are very persistent and might be dispersed by soil, beet seeds, plant material and stable manure. Research has been carried out into the risk of dissemination; relative importance was not determined. Inoculation with diseased soil in a field caused rhizomania in sugar-beets within one year. This implies that even small amounts of soil adhering to plant roots constitute a potential danger. Direct transmission of BNYVV by sugar-beet seeds could not be demonstrated, but, after processing and cleaning seed lots originating from infested fields, the seed waste proved to be contaminated. Cystosores of P betae and, to a lesser extent, BNYVV could pass through the intestine of sheep in fodder experiments carried out with heavily infested sugar-beet tails. Additional keywords: beet necrotic yellow vein virus (BNYVV), Polymyxa betae, sugar-beet.