Many plants from around twenty botanical families host at least one of the beet yellows virus. The table below lists a selection of these plants, the most frequently found in the sugar beet production area.
Four viruses are responsible for beet yellows in France: BYV, responsible for severe jaundice, BChV and BMYV, the poleroviruses responsible for moderate jaundice and BtMV, responsible for beet mosaic.
Weeds
The chenopods and the white chickweed harbor the three families of viruses in the laboratory. In the field, ITB detected the presence of BYV in two lambs quarters samples. Poleroviruses (BChV and BMYV) have a wider host range than BYV: lanceolate plantain, pansies, shepherd’s purse, purple dead nettle or fumitory can in particular be cited. The virus with the least well-known host range remains BtMV.
Intercrop species
Plants used in intercropping, and therefore destroyed before sowing beets, are also hosts for jaundice viruses. The samples carried out by ITB show, for example, that the phacelia hosts the three families of viruses. ITB also detected the presence of BtMV and polerovirus in radishes and mustard (noted as interculture cruciferous in the table). It could not be determined whether the poleroviruses detected in the interculture crucifers were viruses responsible for moderate jaundice or TuYV. Finally, BYV was found in mustard samples.
Rebuilding the aphid’s food chain
In order to determine which viral reservoirs have the most impact on jaundice epidemics, INRAE researchers are working on the identification of reservoir plants that have a real influence on the contamination of beet plots, during the first flights of aphids writes pcrsicae in spring. The final objective is to identify the source plants of viruliferous aphids and to assess the migratory capacity of writes pcrsicae.
The researchers will use molecular tools to analyze the stomach contents of the aphid vectors, in order to detect traces of genomes of plants on which the aphid went to feed before coming to the beets. These data will also be related to the presence, or not, of viruses in insects.
The same molecular tools will be used to differentiate populations of winged aphids. Indeed, according to recent research, although writes pcrsicae or a species capable of living on many species of plants, differentiated populations of this species each having preferences in the choice of their hosts coexist, but mix relatively little.
This new knowledge will make it possible to restrict the range of virus reservoirs, and to adapt prevention and control strategies.
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