The efficacy of some herbicides can be reduced in the presence of calcium in the spray tank . This work was developed to study the influence of calcium on the efficacy of the herbicide carfentrazone-ethyl applied to Euphorbia heterophylla in late post-emergence. The research consisted of two experiments with the calcium concentrations varying from 30 to 240 ppm and from 0 to 1000 ppm in each experiment, respectively. The experimental design was a complete randomized block with four replications. Carfentrazone-ethyl efficacy for weed control was not affected by calcium in the spray tank even at 1000 ppm. The herbicide was also found to be in the control of E. heterophylla at late post-emergence stage, in the dose of 30 g i.a. ha-1.
water; quality; herbicide
