Em São Paulo, ocorrem quatro isolados do vírus que induz o mosaico das nervuras da videira (Vitis spp.), os quais são diferenciados pelos sintomas que provocam em algumas variedades. Para confirmar a identidade desse vírus e o relacionamento existente entre os quatro isolados, foram aplicados os testes DAS-ELISA e TAS-ELISA usando anti-soros comerciais contra o Grapevine fleckvirus (GFkV). As fontes de antígeno foram tecidos de floema de ramos dormentes e de folhas jovens da brotação de primavera de videiras sabidamente infetadas. As reações nos testes imuno-enzimáticos envolvendo os quatro isolados do vírus foram positivas para o anti-soro contra o GFkV. Os resultados foram também positivos para amostras de 66 plantas infetadas de 26 variedades de videira procedentes de 11 regiões vitícolas de São Paulo e de 24 plantas de 12 variedades provenientes dos estados de Minas Gerais, Paraná, Pernambuco, Rio Grande do Norte e Santa Catarina. Extratos de folhas novas e tenras apresentaram valores de absorbância mais consistentes do que extratos de ramos dormentes. Plantas não infetadas foram empregadas como controle negativo. Os resultados obtidos confirmaram que os quatro isolados virais possuem relacionamento sorológico com o GFkV, sugerindo que os mesmos pertencem ao complexo viral que causa o "grapevine fleck disease".

In the State of São Paulo, four different isolates of the virus that induces chlorotic translucent vein break in the minor veins of grapevines (Vitis spp.) were separated by their differential biological behaviour and tested for their relationship to Grapevine fleck virus (GFkV) by DAS-ELISA and TAS-ELISA with commercial antisera against GFkV. Young leaves from spring shoots and dormant cuttings were used for antigen extraction. All infected plants were previously indexed by graft-inoculation to 'Rupestris du Lot'. The four isolates gave positive reactions to the GFkV antiserum. Positive ELISA reactions were observed in 66 samples of 26 varieties, from 11 grape-growing areas from the State of São Paulo as well as 24 samples, of 12 varieties, from five other states of Brazil. Healthy plants consistently gave negative results. Young leaves were better sources of antigen than cortical scrapings of dormant cuttings. The results showed that the four isolates have a serological relationship with the GFkV, suggesting that they belong to the viral complex that induce grapevine fleck disease.

Since 1991, when the whitefly Bemisia argentifolii Bellows & Perring was first described in São Paulo, it dispersed rapidly to all the regions of Brazil. Although the high incidence of geminivirus is correlated with high population of this whitefly, the transmission efficiency of this insect is unknown. To determine whether the B. argentifolii is a vector of BGMV, two experiments were carried out. After an aquisition period of 24 hours on infected beans plants cv. Carioca 80, adults of the whitefly were transferred to seedlings of some cultivars, giving a period of inoculation of 24 hours. In the 1st experiment, the percentage of symptomatic plants were: 25.0% for Carioca 80, 21.0% for Moruna 80, 21.0% for Aeté, 75.0% for Preto and 26.3% for Manteiga. In the 2nd experiment, the percentage of virus transmission were: 63.6% for IAC Carioca and 60.0% for BT-2. The results showed that B. argentifolii is a vector of BGMV and apparently there are no marked differences in efficiency of transmission between this specie and Bemisia tabaci (Genn.).