The stem necrosis of soybean is caused by a virus of the Carlavirus and transmitted for the whitefly Bemisia tabaci, also infectad of beans and identified as Cowpea mild mottle virus (CpMMV). In this work biotype B for transmission of the virus in beans and soy had been carried through tests for determination of the number of necessary whiteflys B. tabaci. In the sequence two other tests had been carried through, with 10 insects for plant. Periods of access to the acquisition (PAA) of 'Jalo' for 'Jalo', and the effect of periods of access to the inoculation (PAI) had been evaluated increase. Visually typical symptoms of carlavirus had been evidenced as mosaic, veinclearing, sistemic necrosis and reduction of growth. It had transmission of the virus for 'BT-2' of beans and 'BRS-132' of soy with only one insect for plant, being more efficient in this last species. The tax of transmission of the virus was bigger with the increase of the number of insects for plant. The PAA was after determined 15 min of time for acquisition, and the increase with 5 min and increasing the period of access the acquisition and inoculation increased it transmission tax.
Carlavirus; vector; Phaseolus vulgaris; Glycine max; cultivars
