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The present work aimed to characterize the dynamics of the weed community in cultivation of cowpea in the semi-arid region of Minas Gerais. The treatments consisted of collecting the weeds 7, 14, 21, 28, 35, 42, 49, 56, 63 days after emergence (DAE); following each collection, the weed community was controlled by mechanical weeding. The collections were carried out using the standard method of the inventory square, randomly launched in the useful area of each plot, collecting all the plants. The number of individuals per species in each plot and the total number per collect were determined. After identifying and counting the species, the phytosociological variables were calculated: Frequency, Density, Abundance, Relative frequency, Relative density, Relative abundance, Relative dominance, Importance value index (IVI), Coverage value index (CVI) and Similarity Index (SI). The species Portulaca oleracea, Amaranthus viridis and Sorghum bicolor presented the largest IVI. It was possible to affirm that the floristic similarity of the weed species that occurred during the cowpea cycle is high. The species Portulaca oleracea, Sorghum bicolor and Senna obustifolia presented the highest CVI values., O presente trabalho teve como objetivo caracterizar a dinâmica da comunidade infestante de plantas daninhas em cultivo do feijão-caupi no semiárido mineiro. Os tratamentos consistiram na coleta das plantas daninhas aos 7, 14, 21, 28, 35, 42, 49, 56, 63 dias após a emergência (DAE), posteriormente foi feito o controle da comunidade infestante por capina mecânica. A coleta de plantas daninhas foi feita pelo método padrão do quadrado inventário, lançado aleatoriamente na área útil de cada parcela, recolhendo todas as plantas. Foram determinados o número de indivíduos por espécie em cada parcela e o número total por coleta. Após a identificação e contagem das espécies, foi realizado o cálculo das variáveis fitossociológicas: Frequência, Densidade, Abundância, Frequência relativa, Densidade relativa, Abundância relativa, Dominância relativa, Índice de valor de importância (IVI), Índice de valor de cobertura (IVC) e Índice de similaridade (IS). As espécies Portulaca oleracea, Amaranthus viridis e Sorghum bicolor apresentaram maiores valores de IVI. Foi possível afirmar que é alta a similaridade florística das espécies de plantas daninhas que ocorreram durante o ciclo do feijão-caupi. Quanto ao Índice de valor de Cobertura (IVC), destacaram-se as espécies Portulaca oleracea, Sorghum bicolor e Senna obustifolia. Palavras-chave: comunidade infestante; Vigna ungiculata; levantamento fitossociológico. Phytosociology of weeds in cultivation of cowpea in the semi-arid region of Minas Gerais ABSTRACT: The present work aimed to characterize the dynamics of the weed community in cultivation of cowpea in the semi-arid region of Minas Gerais. The treatments consisted of collecting the weeds 7, 14, 21, 28, 35, 42, 49, 56, 63 days after emergence (DAE); following each collection, the weed community was controlled by mechanical weeding. The collections were carried out using the standard method of the inventory square, randomly launched in the useful area of each plot, collecting all the plants. The number of individuals per species in each plot and the total number per collect were determined. After identifying and counting the species, the phytosociological variables were calculated: Frequency, Density, Abundance, Relative frequency, Relative density, Relative abundance, Relative dominance, Importance value index (IVI), Coverage value index (CVI) and Similarity Index (SI). The species Portulaca oleracea, Amaranthus viridis and Sorghum bicolor presented the largest IVI. It was possible to affirm that the floristic similarity of the weed species that occurred during the cowpea cycle is high. The species Portulaca oleracea, Sorghum bicolor and Senna obustifolia presented the highest CVI values. Keywords: infestant comunnity; Vigna ungiculata; phytosociological survey.