Disease Note.

Survey for Beet Western Yellows Luteovirus as a Major Component of the Potato Leaf Roll Disease in Central Brazil. M. E. N Fonseca, CENARGEN/EMBRAPA CP. 02373, Brasilia-DF, Brazil . V.L.A. Marinho, and D. C. Monte-Neshich, CENARGEN/EMBRAPA CP. 02373, Brasilia-DF, Brazil; and L. S. Boiteux, NCPH/EMBRAPA CP. 0218, Brasilia-DF, Brazil. Plant Dis. 80:1079. Accepted for publication 3 June 1996. Copyright 1996 The American Phytopathological Society. DOI: 10.1094/PD-80-1079A.

A survey was conducted to ascertain the involvement of beet western yellows luteovirus (BWYV) in the leaf roll disease of potatoes (Solanum tuberosum L.) in central Brazil. One hundred samples of potato plants showing leaf roll symptoms were collected in four sites in Brasilia-DF and in 16 sites in Minas Gerais State. An in vitro germ plasm collection composed of potato clones and cultivars introduced from the U.S., Germany, and Peru was also evaluated. Field-collected leaf samples and tissue-culture plantlets were tested by using a nitrocellulose membrane-enzyme-linked immunosorbent assay ("dot-ELISA") protocol essentially as described for tomato spotted wilt virus detection in Capsicum annuum L. (I). One polyclonal BWYV antiserum (provided by P. E. Thomas, Irrigated Agricultural Research and Extension Center, H. Rodgers Hamilton Laboratory, WA) and two polyclonal potato leaf roll virus (PLRV) antisera (provided by A. N. Dusi, CNPH/EMBRAPA, Brasilia-DF, Brazil) were cross-absorbed with healthy potato sap and purified by chromatography in DEAE-Sephacel. Negative controls consisted of virus-free potato plants obtained from tissue culture. All field samples tested negative for BWYV, whereas 100% were positive for PLRV. Likewise, only PLRV infection was detected in samples obtained from the germ plasm collection. Our work strongly indicates that BWYV has a very reduced epide-miological significance in the potato leaf roll samples from the U.S. and Canada (2).