Influence of Barley Yellow Dwarf Virus-Infected Oats and Barley on Morphology of Aphid Vectors

Abstract

Maturation of aphids as winged forms (alatae) was favored when cereal grain aphids, Sitobion avenae and Rhopalosiphum padi, were reared from birth on barley yellow dwarf virus (BYDV)-infected oats or barley. In 6 experiments involving approximately 300 S. avenae/treatment, 85% matured as alates when reared on BYDV-infected oats, but only 31% matured as alates on healthy oats. Aphid clones from California and New York [USA] produced more alates on BYDV-infected hosts. Similar results were obtained with R. padi reared on healthy or BYDV-infected oats and barley. When 1st and 2nd instar nymphs of R. padi were collected from barley in the field and were reared to maturity, the percentage of R. padi developing as alates from healthy or BYDV-infected barley was 24 and 87%, respectively. Brome mosaic virus-infected barley and insecticide-treated oats also induced increased alate production by R. padi. Differences in the ratio of winged to nonwinged aphid progeny may reflect changes in host plant physiology that affect aphid nutrition and development. Cereal grain aphids developing on infected plants are more likely to mature as alates, which would favor aphid dispersal and secondary spread of BYDV.