Epidemiology of bean common mosaic virus in the Jordan Valley

Three isolates recovered fom bean seeds of different cultivars were identified as bean common mosaic virus (BCMV), on the basis of symptomology, host range, electron microscopy and serology. None of the BCMV infected seedlings of Picker Garden Bean cultivar showed any viral symptoms. Both, La-Vict and Derby cultivars, had a lower number of infected seedlings, with viral symptoms, than those proved to be BCMV infected either by bioassay or ELISA; whereas all BCMV infected seedlings of other bean cultivars showed viral symptoms. Bean seeds of seven selected cultivars carried BCMV in different rates. In the growing - on test, the highest rate was 38% in Bean Lolita-2 cultivar and the lowest 10% in Derby cultivar. However, the detection level of the bioassay test was not significantly different from the ELISA for all tested samples. The three BCMV isolates were differentiated according to their synptoms on Phaseolus vulgaris L. cv. Dubbele Witte. These isolates were found in the infected seedlings of the assayed bean cultivars with different percentages. Incidence of BCMV isolate I ranged from 50% - 85% in all tested bean cultivars; whereas the incidence of BCMV isolate III did not exceed 15%. Three hundred and nine weed samples belonging to thirty four weed species, were assayed for BCMV infection. None of these tested samples showed to be virus infected. Weed samples were collected either from different bean fields along the Jordan Valley during 1994 and 1995 growing season, or during the summers of 1994 and 1995. Seventeen wild or cultivated leguminous plant species were assayed for their response to BCMV artificial inoculation. Lupinus termis Forsk., Lupinus varius L., and Lens culinaris L. were proved to be infected with the virus. Weed flora survey study was conducted during 1994 and 1995 in different bean fields in the Jordan Valley. The highest weed diversity was recorded in Abu-Obeida bean field; whereas, the lowest - in Ghor Al-Safee bean fields. In all surveyed bean fields, Chenopodium murale L. and Amaranthus gracilis Desf. had the highest frequency (85%) and highest density (18.8 plant/m** (2)), respectively. On the other hand, the lowest frequency and density (5% and 0.1 plant/m** (2)), respectively, was recorded for several weed species in different selected bean fields in the Jordan Valley during 1994 and 1995