Abstract

ANZALONE, Alvaro; RUIZ, Mágrit; ZAMBRANO, Cástor  and  ORTIZ, Aída. Evaluation of Zea mays L. and Phaseolus vulgaris L. as bioindicators of imidazolinone herbicide in soil. Bioagro [online]. 2011, vol.23, n.2, pp.121-128. ISSN 1316-3361.

This research was conducted to evaluate the behavior of species Phaseolus vulgaris and Zea mays as bioindicators of the presence of imidazolinone herbicides in the soil. Two experiments were conducted under a completely randomized design with eight treatments and ten replications. The objectives were to identify the species that best behaved as an indicator (experiment 1), and to validate the use of selected species, characterized through the use of dose curves-response using a log-logistic model (experiment 2). The plants were grown in pots with soil supplemented with eight different concentrations of a mixture of imidazolinone (imazethapyr and imazapyr). In the second experiment, a concentration control was added to corroborate the model and to evaluate its predictive capacity. In both experiments, the aerial dry biomass of plants was determined. Corn was the species that best behaved as bioindicator. The obtained dose-response curves were asymptotic and asymmetric with a rapid decrease of biomass with the increase of herbicide concentration in soil. The concentration estimated by models that reduced by 10 % corn biomass corresponded to 8.3 and 13.6 % of the applied commercial rate (200 g·ha^-1) for experiments 1 and 2, respectively, thus suggesting a high sensitivity of the species to the herbicide. As for the predictive ability of the model, the estimated herbicide concentration in soil deviated only 10.9 % of real value.

Keywords : Imazapyr; imazethapyr; bioassay.