HOST RANGE OF FIELD DODDER (CUSCUTA CAMPESTRIS YUNCKER) IN SUGAR BEET FIELDS (Example from Northeastern Croatia)

Dodders are cosmopolitan parasitic rootless and leafless plants, only minimally photosynthetic, and entirely dependent on the host. Among them, field dodder (Cuscuta campestris Yunck.) is the most widely distributed dodder species that can cause a serious problem in sugar beet production in many areas around the world. Depending on the severity of infestation, dodder can reduce the sugar beet yield by 20-100%. Distribution and abundance of field dodder has become significant in northeastern Croatia sugar beet fields, showing 30% of high and 10% of severe dodder infestation. A similar pattern has been observed in the surrounding fields and rural habitats with severe dodder attack occurring particularly in alfalfa fields. Dodder has a broad host range, and has preference. During this study, a total of 28 weed species served as dodder hosts. The host weed species having a strong association with the sugar beet crop were Conyza canadensis, Solanum nigrum, Datura stramonium, Amaranthus retroflexus and Atriplex patula. However, many other weeds can support dodder development in other fields, field borders and non-crop areas. Their soil can become a reservoir of dodder seeds during the years when non-host crops are grown. They are Polygonum aviculare, Polygonum persicaria, Polygonum lapathi-folium, Convolvulus arvensis and Chenopodium album.