[Rizomania. Cultivation by infestation and noninfestation]

azote beta vulgaris control cultural cultural control disease resistance fertilisation fertilizer application lutte culturale nitrogen plant viruses plantas libres de virus plante indemne de virus remolacha azucarera rendement rendimiento resistencia a la enfermedad rhizomania rhizomanie rizomania sugar beet symptome symptoms variedades varieties virus de las plantas yields