Occurrence of Asparagus Virus I and Asparagus Virus II on Asparagus in Delaware. T. A. Evans, Department of Plant and Soil Science, University of Delaware, Newark 19717-1303. Plant Dis. 75:1075. Accepted for publication 3 May 1991. Copyright 1991 The American Phytopathological Society. DOI: 10.1094/PD-75-1075B.
During the 1987, 1988, and 1989 growing seasons, surveys of 15
asparagus (Asparagus officinalis L.) production fields in Delaware
resulted in the detection of two viruses, evidenced by appearance on
Chenopodium quinoa Willd. of chlorotic local lesions and necrotic
local lesions 5 and 10 days, respectively, after mechanical inoculation
(1). Systemic mottling of C. quinoa was observed only on plants with
local chlorotic lesions. On the basis of particle morphology, host range,
symptomatology, Ouchterlony gel double-diffusion tests, and serologically
specific electron microscopy, the viruses were identified as
asparagus virus I (AV-I), a potyvirus, and asparagus virus II (AVII),
an ilarvirus (2). AV-I was detected in only three of 15 asparagus
plantings, with an incidence of less than 5%. AV-II was detected in
12 of 15 plantings, with a 10-40% incidence. This is the first report
of AV-I and AV-II in Delaware.