Influence of beet soil-borne virus on mechanically inoculated sugar beet

Seven-day-old seedlings of three different sugar-beet varieties (Carla, Rizor and Desiree) were inoculated mechanically with the Ahlum isolate of beet soil-borne virus (BSBV) in crude sap from infected leaves of Chenopodium quinoa. Control plants were mock-inoculated with sap from healthy C. quinoa. After potting up, the plants were arranged in a randomized block design on nine neighbouring benches in a glasshouse. Plants were sampled after 11 weeks, the fresh weight of the tap roots determined and the presence of virus checked by ELISA. Considerable variation in tap-root growth was observed between benches. Overall, BSBV inoculation reduced tap-root weight of Rizor and Carla by c. 20%. Problems arising in attempts to assess yield loss due to BSBV in naturally infected sugar beet are discussed.