Para estudar as interações entre o mosaico-em-desenho e a ferrugem e mancha angular do feijoeiro foram determinados os parâmetros monocíclicos das doenças e a eficiência fotossintética das plantas das variedades Rosinha G-2 e Carioca Comum os parâmetros monocíclicos das duas doenças fúngicas em plantas pré-infectadas ou não com vírus na temperaturas de 9, 12, 15, 18, 21, 24 e 27ºC para ferrugem e de 15, 18, 21, 24, 27 e 30ºC para mancha angular. Independente da pré-infecção viral para ferrugem o processo infeccioso e a colonização foram favorecidos pelas temperaturas de 17 e 18ºC. O menor período latente ocorreu a 21ºC. Para mancha angular o processo infeccioso e a colonização foram favorecidos a 24ºC na qual teve o menor período de incubação nas duas doenças fúngicas a pré-infecção viral reduziu todos parâmetros monocíclicos exceto período latente e de incubação. A eficiência fotossintética foi reduzida nas plantas doentes em maior proporção que a área afetada pela lesão as plantas com vírus por apresentarem baixo nível de infecção fúngica se comportaram semelhante as plantas só com vírus. Na análise dos parâmetros de fluorescência concluiu-se que o modo de ação dos patógenos biotróficos é diferente do hemibiotrófico. Foi observado um menor dano ao aparato fotossintético nas plantas com patógenos biotróficos

Monocyclic parameters of diseases and the photosynthetic efficiency were determined in plants of Rosinha G-2 and Carioca Comum varieties infected with one or more pathogens, in order to study the interaction between bean "mosaico-em-desenho" and two fungaI diseases, bean rust and angular leaf spot. Monocyclic parameters of rust and angular leaf spot (infection frequency, incubation or latent periods, lesion growth rate, final lesion size and disease severity) were determined in virus-free and virus infected plants at different temperatures (9, 12, 15, 18, 21, 24, and 27°C to bean rust and 15, 18, 21, 24, 27, and 30°C to bean angular leaf spot). For Uromyces appendiculatus, the optimum temperatures to infectious process and colonization were 17 and 18°C, respectively, independent of previous virus infection. The shortest latent period occurred at 21°C. For Phaeoisariopsis griseola, the optimum temperature to infectious process and colonization was 24°C, independent of previous virus infection. The shortest incubation period occurred at 24°C. Previous virus infection significantly reduced alI monocyclic parameters in both fungal diseases except the bean rust latent period and the angular leaf spot incubation period. Photosynthesis efficiency, measured by net CO₂ assimilation, decreased in infected pIants with one or more pathogens. The net CO₂ assimilation reduction by fungal diseases was proportionally higher than that expected based on the reduction caused by injured leaf area and decrease of leaf chlorophyll content. As the leveI of fungal infection is low in virus pre-infected plants, plants infected with virus had the same photosynthesis efficiency than plants infected with two pathogens. By fluorescence parameters' analysis, it was concluded that the way by which biotrophic pathogens act is different than hemibiotrophic ones. Lower photosynthetic apparatus damage was observed in infected plants with biotrophic pathogens