Practices to Mitigate Indaziflam-Injured Hybrid Bermudagrass.

Indaziflam is a PRE herbicide commonly used in turfgrass systems that in isolated cases has caused adverse effects on hybrid bermudagrass [Cynodon dactylon (L.) Pers. × Cynodon transvaalensis Burtt-Davy] growth.  Field research was initiated in 2015 to evaluate practices to mitigate adverse ‘Tifway 419’ hybrid bermudagrass injury following fall (October 14, 2015) and spring (March 10, 2016) indaziflam applications (49 g ai ha^-1).  A factorial arrangement of mitigation practices including activated charcoal application (448 kg ha^-1), hollow-tine aerification and verticutting, as well as fertility programs (fall-only, spring-only or none) were evaluated in plots comprised of established and root-compromised hybrid bermudagrass.  Mitigation practices were conducted on May 9, 2016.  Overall, adverse effects on hybrid bermudagrass growth were more pronounced in root-compromised than established plots.  At 4 wk after mitigation practice (WAMP), all activated charcoal treatments resulted in increased hybrid bermudagrass cover in root-compromised plots (69 to 77%) compared to indaziflam treated-no practice (59%).  Additionally, activated charcoal alone was a comparable, or superior mitigation practice compared to all other evaluated practices from 4 to 10 WAMP.  Hollow-tine aerification and verticutting alone, or in tandem were the only practices to result in reduced cover compared to no cultural practice in established and root-compromised plots, suggesting they should not be employed to mitigate indaziflam-hybrid bermudagrass injury.  When significance was detected, spring fertility applications promoted hybrid bermudagrass recovery, while fall fertility did not vary from the nontreated.  Although adverse effects on hybrid bermudagrass from indaziflam rarely occur, this research provides information for turfgrass managers to mitigate injured areas in lieu of re-establishment.