LAUSR

Fifty-five soil samples were collected from sugarbeet fields with rhizomania occurrence in the region of Tadla. BNYVV was ascertained by RT-PCR in 40 out of 55 fields surveyed and the positive samples were subsequently examined for the presence of the different pathotype of BNYVV. Using the same technique, a survey was simultaneously undertaken to identify the occurrence of other soil-borne viruses, which might frequently associate with BNYVV such as beet soilborne virus (BSBV), beet soilborne mosaic virus (BSBMV) and beet virus Q (BVQ). Results indicated that most samples were infected with A-type BNYVV, but only 9% of the samples were positive for B-type BNYVV. BNYVV (72.7%) was the most frequently detected, followed respectively by BSBV (36.36%) and BVQ (30.9%). However, P-type BNYVV was not detected at all. Our results also indicated the likely absence of BSBMV in the Tadla region. Surprisingly, among the 40 BNYVV-infected samples, 17 were also infected with BVQ and 20 with BSBV. In conclusion, BSBV occurred in triple infections with BNYVV and BVQ. In addition, there was only one sample revealed positive for both viruses BNYVV-B and BVQ and four samples for BSBV infection. Therefore, this study is the first investigation of BSBV and BVQ in fields-grown sugarbeet of Morocco.