Seleção de espécies indicadoras de resíduos de dicamba no solo

The introduction of dicamba resistant soybean cultivars will increase the use of this herbicide in weed management in Brazil. Part of all applied herbicide reaches the soil, causing intoxication of crops grown in succession and contamination of soil and water. In this sense, the selection of indicator species for biassaying becomes an important tool to evaluate the behavior of this herbicide in the environment. The objective of the study was to identify plants susceptible to the dicamba herbicide, in order to indicate the herbicide residue in the soil. The study was conducted in a greenhouse, using a completely randomized design, in a 6x10 factorial scheme, with four replications. The first factor was composed of plant species (Phaseolus vulgaris, Citrullus lanatus, Cucumis sativus, Beta vulgaris, Glycine max and Solanum lycopersicum), and the second factor was the dicamba doses (0; 4.5; 9.0; 18.0; 36.0; 54.0; 72.0; 108.0; 144.0; 216.0 g de e.a ha-1), using like inert substrate washed sand. At 14 and 21 days after emergence the plants were assigned to intoxication evaluationand collected the aerial part. The highest values of visual intoxication were observed in bean and soybean crops. Watermelons, cucumbers, beets and tomatoes also behaved sensitively, however, with higher C50 values. The visual symptoms of intoxication and dry matter production highlight the bean as the most suitable species for the evaluation of the presence of residues of the dicamba herbicide.