Interactions between the Grasses Phalaris arundinacea, Miscanthus sinensis and Echinochloa crus-galli, and Barley and Cereal Yellow Dwarf Viruses

The grass species Miscanthus sinensis, Echinochloa crusgalli and Phalaris arundinacea may be useful biomass crops. In glasshouse inoculations with two isolates of Barley yellow dwarf virus (BYDV)-MAV and BYDVPAV and one of Cereal yellow dwarf virus (CYVD)- RPV, E. crus galli was infected by all three virus isolates, P.arundi nacea by BYDV-MAV and CYDVRPV, but M.sinensis only by BYDV-MAV. All three hosts became very difficult to infect after several weeks growth. Symptoms were inconspicuous;dry matter yield losses ranged from c. 20–40%. Aphids acquired all three virus isolates from E.crus-gall i, but more efficiently from 5 than 26-week-old plants. Only BYDV-MAV was acquired from P.arundi nacea and M.sinen sis. Plants of each species and of Avena sativa were grown outdoors between May and July in 1994 and 1995. Young plants of each species were exposed for successive 2-week intervals during the same periods. Vector populations were higher on A.sativa and P.arundi nacea than on E.crus-gall i and M.sinen sis, and more plants of these species became infected. In 1994 only BYDV-MAV was detected. In 1995 BYDV-MAV, BYDV-PAV and CYDV-RPV were all detected;BYDV-MA V was again the virus isolate most frequently found