Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 7/1/2000
Publication Date: N/A
Technical Abstract: Schizaphis graminum, a widespread and destructive pest of cereals, is also an efficient vector of several luteoviruses that cause barley yellow dwarf (BYD). Five of 9 biotypes of S. graminum examined efficiently transmit multiple BYD viruses, but differ in the viruses transmitted. Three biotypes transmit the viruses inefficiently and one does not transmit. Biotypes adapted to wild grasses are better vectors than biotypes adapted to agronomic crops. Feeding behavior or amount of virus acquired during feeding are not correlated with transmission efficiency. Interestingly, vector competence is developmentally regulated for BYDV-SGV but not PAV or RPV. SGV acquired by 1st and 2nd instar vectors is retained and transmitted throughout the life of the insect. SGV acquired by adults is retained in the hemocoel, but not released via the salivary system. Aphid populations differing in vector competence were induced to produce sexual forms and mated. The inheritance and molecular genetics of circulative transmission is being examined in progeny maintained as clonal lines via parthenogenetic reproduction.