This summary describes an aphid (Aphis gossypíí) transmission of a cotton virus ("mosaico-das-nervuras", "Ribeirão Bonito" type, also called "blue disease"). It was developped in greenhouse in Coodetec, Cascavel, Paraná State. Plants evaluation occured 48 days after platting, 28 days after the first exposure to the aphids. This method was very efficient to discriminate resistant and susceptible plants. Today, it is used routinely and used for others experimental genetical works such as virose resistance and also re selectioning pure genetic nuclei from various Coodetec's lines and varieties.