Pearl millet is an important species cultivated in succession in the Brazilian savannah. Although the herbicide atrazine presents a potential use in this culture, little has been done to determine the susceptibility of this species according to its stage of development at the time of application. This study aimed to evaluate the selectivity of atrazine to millet (Pennisetum glaucum), determining the maximum dosage of implementation and the culture stages with lower sensitivity. Two experiments were conducted under greenhouse conditions, by first establishing the selectivity of the herbicide to cultivars ADR-300, ADR-500 and ADR-7010. Subsequently, cultivar ADR-500 was evaluated in terms of dose response of atrazine during the phenological stage of development. The experiment was arranged in a completely randomized design in a factorial scheme 5 x 3, with four replications, corresponding to five atrazine doses (0; 0.5; 1.5; 2.5 and 4.0 kg a.i. ha-1) applied at three millet growth stages (two, four and eight expanded leaves). ADR-500 cultivar showed the highest susceptibility among the cultivars evaluated. Applications made at the early stages of millet growth promoted the highest levels of phytotoxicity symptoms, reducing the number of shoots and dry biomass accumulation of the aerial part. These results were intensified by increasing the atrazine dose. With respect to ear mass, doses less than 1.5 kg ha-1 did not significantly affect this variable, regardless of the stage of application. It was concluded that atrazine doses below 1.5 kg ha-1 can be safely applied on growing millet, when the plants present four or more leaves at the time of application.
herbicides; triazines; post-emergence; pearl millet cultivars
