Host Range of Polymyxa betae Keskin which spread in Syria and the ability of the infected Weeds to transfer it to Sugar beet

Polymyxa betae is an important vector of many viral diseases and widespread in Syria. It was necessary to determine the host rang of Syria's isolate of the P. betae in the local plant species and their role as alternate host to P. betae, as well as its role to transfer the P. betae to sugar beet cv. 186 dicotyledonous and monocotyledonous plant species were collected during the years 2007 - 2010 from sugar beet fields with a focus on Rhizomania infected fields regardless the planted crop. 10 dicotyledonous and two monocotyledonous plant species were positively tested with naturally infection of Polymyxa spp. In addition, 106 dicotyledonous and monocotyledonous plant species kindly provided by the BASF AG (Germany) were tested in soil infected with Syrian isolate of P. betae only. After microscopic examination only 23 dicotyledonous plants species belong to 10 families were positively tested with P. betae. This study showed for the first time the infection of Cabbage, Brassica oleracea and Radish, Raphanus sativus with P. betae. All Weeds were infected with Syrian isolate of P. betae were able to transfer it to the roots of sugar beet. Some of weed species which show in Literature that potentially-infected with P. betae did not infect with Syrian isolate.