|
Disease Note. The Russian Wheat Aphid, Diuraphis noxia, Confirmed as Vector of Brome Mosaic Virus in North America. V. D. Damsteegt, USDA-ARS, Fort Detrick, Building 1301, Frederick, MD 21701. A. D. Hewings, USDA-ARS, Fort Detrick, Building 1301, Frederick, MD 21701.. Plant Dis. 72:79. Accepted for publication 11 August 1987. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/PD-72-0079. Diuraphis noxia Mordw. causes serious losses of wheat (Triticum
aestivum L.) in South Africa. The aphid was identified in Mexico in
1980 and the southern plains of the United States in 1986 and is
considered to be a very damaging pest. D. noxia has been reported to
transmit several grain viruses, including brome mosaic virus (BMV),
which previously had no known insect vector (I). Nonpersistent and
persistent modes of transmission of a Nebraska isolate of BMV were
tested with a Texas clone of D. noxia on Baart wheat and Henry barley
(Hordeum vulgare L.). Four weeks after inoculation, each test plant
was harvested for ELISA analysis and for mechanical back inoculation
to individual Henry seedlings. All 48 plants assayed in the persistent
tests were symptomless, yet eight were positive for BMV by ELISA and
six were positive when bioassayed on indicator hosts. BMV-infected
indicator hosts showed typical linear yellow lesions. All plants that were
positive by bioassay were positive by ELISA. No transmission was
obtained in nonpersistent experiments. D. noxia appears to transmit
BMV inefficiently in the persistent manner but is potentially a very
threatening vector because of high natural populations in graminaceous
hosts. |