Resumo: O levantamento fitossociológico é muito importante para conhecer a comunidade infestante e, com isso, realizar de forma mais adequada o manejo das plantas daninhas. Objetiva-se com este trabalho identificar as principais espécies de plantas daninhas em áreas de bananicultura recém-implantadas e em produção na região do norte de Minas Gerais. Para caracterização e estudo fitossociológico da comunidade infestante, avaliaram-se duas áreas de banana-prata, ambas com 10 hectares, nas quais se utilizou o método do quadrado inventário, lançado aleatoriamente por meio de um caminhamento em ziguezague. Avaliaramse as seguintes variáveis fitossociológicas: frequência, frequência relativa, densidade, densidade relativa, abundância, abundância relativa, índice de valor de importância, índice de valor de importância relativa e índice de similaridade. Na área recém-implantada foram encontradas 17 espécies, divididas em 15 gêneros e dez famílias, destacando-se, dentre essas, as famílias Fabaceae e Poaceae. Abstract: Phytosociological surveys are very important when identifying an invasive community in order to carry out more suitable weed management. The aim of this study therefore, was to identify the main species of weeds in banana plantations, both newly-planted and under production, in the northern region of the State of Minas Gerais, Brazil. For the phytosociological study and characterisation of the weed community, two areas of 'Prata' bananas, both of 10 hectares, were evaluated using the method of inventory squares, which were randomly thrown along a zigzag path. The following phytosociological variables were evaluated: frequency, relative frequency, density, relative density, abundance, relative abundance, importance value index, relativeimportance value index and similarity index. In the newly-planted area, 17 species were found, divided into 15 genera and ten families, with the Fabaceae and Poaceae families being prominent. The species with the highest importance indices were: Sida spp. (62.38), Galinsoga parviflora (32.36), Amaranthus hybridus (24.93) and Ipomoea hederifolia (19.61). In the area under production, 12 species, 12 genera and ten families were found, with the Asteraceae family being prominent. The species with the highest relative-importance value indices were: Commelina benghalensis (39.19), Emilia fosbergii (34.42) and Amaranthus hybridus (32.96). Between the two areas, there was a difference in the mean values for density, and for the number of plants with C4 metabolism; five in the newly-planted area, and three in the area under production. The Similarity Index between the two areas was 48.27%, with seven species common to both areas.

This study aimed to identify some of the main weed species in the pineapple crop grown in northern Minas Gerais state, Brazil. The phytosociological survey was carried out in two seasons, spring-summer and fall-winter, in a pineapple cultivation area of Unimontes, using the square inventory method (0.25 x 0.25 m). The samples were identified and quantified by families, genera and species, evaluating: frequency, relative frequency, density, relative density, abundance, relative abundance, importance value index, relative importance value index and similarity index. In the spring-summer period, ten species were identified, distributed in nine genera and eight families, highlighting the Euphorbiaceae and Poaceae families, with two species each. The species with the highest importance value indexes were Cyperus iria (77.29), Cynodon dactylon (51.99) and Euphorbia heterophylla (45.46). In the fall-winter period, six families, seven genera and nine species were identified, since three of the Euphorbiaceae family, with more species. The species that showed greater importance value indexes in the fall-winter period were Amaranthus hybridus (48.64), Cyperus hiris (48.11) and Euphorbia hirta (45.06). The similarity index was 84.21%, with 11 species in common, demonstrating a high homogeneity between the two evaluated periods.