Yield Responses of Six White Clover Clones to Virus Infection Under Field Conditions. C. Lee Campbell, Assistant Professor, Department of Plant Pathology, North Carolina State University, Raleigh 27695. James W. Moyer, Associate Professor, Department of Plant Pathology, North Carolina State University, Raleigh 27695. Plant Dis. 68:1033-1035. Accepted for publication 23 July 1984. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/PD-68-1033.

One hundred twenty vegetatively propagated plants from each of six Tillman white clover seedlings were grown in the field under natural virus-infection pressure during 1981 and 1982. Assay on Chenopodium quinoa indicated that 33% of plants were infected during 1981 and 85% of plants were infected by September 1982. Enzyme-linked immunosorbent assay revealed incidence of alfalfa mosaic virus (AMV), clover yellow vein virus (CYVV), and peanut stunt virus (PSV), with predominance of CYVV and PSV. Differences (P<0.10) between yields of virus-free and virus-infected plants were found for two, three, and five of the clones on 17 May, 11 June, and 8 July 1982, respectively. Maximum yield reductions were 47.2, 33.9, and 57.1% at the three harvest dates, respectively.