Susceptibility of Weed Populations to Glyphosate in Banana Plantations of the Department of Magdalena, Colombia

Weeds are a limiting factor in banana production in Colombia. To contribute to its management, we proposed to evaluate the structure and diversity of weed communities in four banana producing areas (Alta, Media, Baja, and Norte) of the Magdalena department. Surveys were carried out during 2016 and 2017 by systematic sampling using 1m(2) squares, on farms with chemical, coverage, and mechanical weed control methods, selected in each area; the frequency, density and dominance of weeds were calculated to estimate the importance value index (IVI), the alpha diversity and the similarity index of Bray-Curtis. One hundred twenty-two species included in 93 genera and 39 families were identified. Poaceae and Cyperaceae presented the highest specific richness and Commelinaceae the highest IVI. Commelina erecta, Axonopus compressus and Melothria pendula were the species of greatest ecological importance in the plantations. Phytosociological parameters differ between zones and between control methods. The areas with greater and lesser diversity were Norte and Baja, respectively. There was greater similarity between Media and Baja and Media and Alta zones, while Norte was the most dissimilar. Few species were very abundant and frequent, indicating that diversity tends to be low. The agroecological conditions of each zone and the control methods used influence phytosociological parameters and species diversity, determining the structure and composition of weed communities associated with the crop.