FEATURE
Carotenoid Inhibiting Herbicides Increasing in Use DESPITE INJURY CONCERNS By Scott McElroy, Professor, Auburn University Gracie Cotter, Graduate Research Assistant, Auburn University Debra Smitherman, Graduate Research Assistant, Auburn University
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arotenoid-inhibiting herbicides are valuable in turfgrass management. There are two carotenoid inhibitors available – Tenacity (mesotrione) and Pylex (topramezone). Tenacity has both pre and postemergence control of crabgrasses and some broadleaf weeds. When used in multiple application strategies they can control goosegrass and Poa annua as well. Pylex has become well known for control of goosegrass and also has activity on crabgrasses and miscellaneous broadleaf weeds. On the face of it, these two herbicides seem ideal for use in turfgrass management; however, as anyone who has used them knows, it can be challenging to balance out the injury and the desired level of control. Both herbicides can cause injury to some, if not all, desirable turfgrasses they are labeled on. The injury presents as an intense white color, or as it is commonly called, “bleaching”. Even though tolerant turfgrasses may present with white or bleached symptoms, these symptoms can quickly abate, and turfgrass can actually be more intensely green post-recovery.
Figure 1. Smooth crabgrass control with Pylex and Drive 28 days after treatment. 20 May 2025 – 7 DAT
Non-Treated
Pylex 0.5 fl oz/a plus Drive XLR8 64 fl oz/a 10 June 2025 – 28 DAT
Non-Treated
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Pylex 0.5 fl oz/a plus Drive XLR8 64 fl oz/a
TENNESSEE TURFGRASS AUGUST / SEPTEMBER 2025 Email TTA at: info@ttaonline.org
