Jose V Fernandez and D Calvin Odero
University of Florida Everglades Research and Education Center, Belle Glade, United States of America; dcodero@ufl.edu
Field studies were conducted in 2014-2015 and 2015-2016 to determine preemergence (PRE) and early postemergence (POST) control of fall panicum in sugarcane with the premix of atrazine, mesotrione, and S-metolachlor on organic and mineral soils of Florida, and to determine the response of sugarcane varieties to PRE and early POST application of the premix. The premix applied PRE provided >80% control of fall panicum at 100 days after treatment (DAT) when there was adequate precipitation prior to and after application. As an early POST herbicide, the premix provided variable control of fall panicum of 50% to 70% on organic soil at 100 DAT compared to 45% to 83% on mineral soil. It did not provide adequate control at the proposed use rate on larger plants, particularly on organic soil. Acceptable control of fall panicum at the proposed labeled rate can be achieved when PRE treatments are followed by incorporation by rainfall or when early POST applications are made on much smaller fall panicum than in this study, otherwise higher rates than currently proposed will be required to achieve acceptable early POST control. There was no injury on all sugarcane varieties from PRE or early POST application of the premix at all rates used in the study indicating that sugarcane exhibited tolerance to herbicides in the premix. Because herbicide options are limited in sugarcane cultivation, the premix is a welcome addition for use in sugarcane providing growers with the flexibility to use it as a PRE or early POST herbicide especially when it cannot be used PRE under dry conditions associated with sugarcane planting in Florida.