Print version ISSN 0100-8358
FREITAS, F.C.L. et al. Weed control in ornamental plant seedling production. Planta daninha [online]. 2007, vol.25, n.3, pp. 595-601. ISSN 0100-8358. http://dx.doi.org/10.1590/S0100-83582007000300020.
This study aimed to evaluate efficacy of oxyfluorfen in controlling Pilea microphylla for the production of ornamental plant shoots. Two experiments were carried out in a randomized block design, arranged in a factorial scheme 2 x 7, with three replicates. One trial was composed by three ornamental plant species (Zantedeschia aethiopica, Strelitzia reginae and Archontophoenix cunninghamiana) and seven oxyfluorfen rates (0, 24, 72, 144, 216, 288 and 360 g ha-1), sprayed in a total area; the other trial was composed by the same species and seven oxyfluorfen concentrations (0.00000, 0.00036, 0.00072, 0.00144, 0.00288, 0.00576 and 0.01152% of a.i.) applied directly as spray, without reaching the ornamental plant leaves. Each experimental unit was represented by a pot with an ornamental plant shoot, infested with Pilea microphylla. At 15, 30 and 60 days after application (DAA) visual evaluations of the control on P. microphylla and toxicity on ornamental plants were carried out. For the total area spray, the A. cunninghamiana plant pots demanded high herbicide doses due to this species' larger foliar area, during application, making the herbicide contact with weeds difficult. Still in this application modality,light intoxication symptoms were observed in the ornamental plants, being more evident in the A. cunninghamiana plants. For the direct spray modality, no interaction among the factors, species and herbicide concentration, nor herbicide behavior differences were observed for the characteristics evaluated. Intoxication was not observed in the ornamental plants in none of the treatments evaluated, for the direct spray modality. Efficient P. microphylla control was verified for rates above 90% at 300, 320 and 340 kg ha-1 of oxyfluorfen, plants of Z. aethiopica, S. reginae and A. cunninghamiana, respectively, in total area application, and high concentrations over 0.0018%, in the direct spray modality at 30 DAA.
Keywords : Oxyfluorfen; Pilea microphylla; Zantedeschia aethiopica; Strelitzia reginae; Archontophoenix cunninghamiana.