To evaluate the effect of mite density of B. yothersi and B. californicus on acquisition and transmission of Cilevirus leprosis. To determine the effect of mite density on virus acquisition, three densities of B. yothersi (5, 10, and 15 adult females) were exposed to a virus source (orange fruits exhibiting symptoms of Cilevirus leprosis) for seven days. For B. californicus only the 15-mite density was evaluated. Control treatments consisted of the same densities for both mite species; however, in these treatments, mites were allowed to feed on non-infected oranges. For transmission experiment, only B. yothersi was used. Mites were exposed to a virus source as described previously, using the same densities (5, 10, and 15 adult females), each with its corresponding control treatment. After seven days of feeding, all mites were transferred to seven-day-old bean plants (Phaseoulus vulgaris var. Jamapa). The proportion of mites positive for the virus in each treatment was determined using RT-PCR. RNA from each individual mite was extracted using the ZR Tissue & Insect RNA MicroPrep kit, and cDNA was synthesised using Sensiscript. Conventional PCR assays to detect the virus were done using the primers of Locali et al. (2003). For virus quantification in mites from each treatment, a TaqMan probe and one set of primers were designed using the movement protein gene region of the complete and partial RNA2 sequences of CiLV-C. The primers (F: TGA CAC CGA ACG ATA TGA TTT CTC, R: ATA TCT GCC TAA AAG ACT CCA CAG) and the TaqMan probe (CCC CAG CGT CTT CAG CTT TAC GGT) were designed on the software AlleleID 6 and synthesized. FAM and BHQ1 were used to label the probe at the 5' and 3' end, respectively. For the bean leaves, RNA was extracted from 10 mg of leaf tissue using the Quick-RNA Plant Miniprep kit, and virus quantities were estimated as describes previously. Mite density did not affect the proportion of B. yothersi mites acquiring Cilevirus leprosis but affected the quantity of virus acquired. We obtained 100% infection of bean leaves, although no significant differences in viral quantity were observed among treatments. B. californicus did not acquire the virus. Our findings provided new insights into the effect of mite-virus interactions in the transmission of this virus.