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Ecology and Epidemiology

Variations in Virus Content Among Individual Leaves of Cereal Plants Infected with Barley Yellow Dwarf Virus. Ana-Maria N. Pereira, Graduate assistant, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, Present address: Departamento de Proteccao de Plantas, Universidade de Tras-os-Montes e Alto Douro, 5000 Vila Real, Portugal; Richard M. Lister, professor, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907. Phytopathology 79:1348-1353. Accepted for publication 25 July 1989. Copyright 1989 The American Phytopathological Society. DOI: 10.1094/Phyto-79-1348.

Infected cereal plants, whether symptomatically tolerant or sensitive to barley yellow dwarf virus (BYDV), showed wide variations in virus content (as assessed by enzyme-linked immunosorbent assay [ELISA]) among different leaves on the same plant, and also among leaves in the same position (i.e., of the same age) on different plants. Variations were more pronounced with Clintland 64 oats than with several barley and wheat cultivars, but in all cases were sufficient to indicate that comparisons of virus acquisition efficiency by allowing aphids unrestricted access to intact plants would be difficult. Comparisons involving acquisition feeding on individual leaves of known virus content should be more reliable. The results also illustrate the danger of relying on ELISA of individual leaves or leaf samples for estimating differences in virus productivity between cultivars, and that even qualitative ELISA diagnosis requires adequate samplings of different leaves.