Evaluation of the Effect of Previous Cultural of Sugar Beet on the Viral Inoculum Load of ?Beet Necrotic Yellow Vein Virus? in Morocco

This study aimed to evaluate the effect of previous crop of sugar beet on the viral inoculums load -Beet Necrotic Yellow Vein Virus- (BNYVV). In Morocco wheat, corn, sesame and alfalfa are used in rotation with sugar beet the role of this plants to transmit BNYVV and Polymyxa betae was determined by growing plants in naturally infested soils from rhizomania outbreaks in Morocco. After 28 days of culture analysis of their roots by DAS- ELISA and under the microscope showed the absence of virus and its vector fungus in the roots of these plants. Only P. betae isolates from sugar beet were found to be able to transmit BNYVV back to sugar beet. Therefore it seems likely that the plants used in rotation in Morocco play not a role in the spread of rhizomania disease compared to that of sugar beet.