Sod Regrowth of St. Augustinegrass after Preemergence Herbicide Application
- Lambert B. McCarty *,
- D. Wayne Porter and
- Daniel L. Colvin
St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] sod production involves stolon regeneration from strips left from the previous harvest. Field studies were conducted to evaluate stolon regrowth and rooting following preemergence application of herbicides, lterbicities evaluated were atrazine [6-chloro-N-ethyl-N'-(1-methylethyl)-l,3,5-triazine-2,4-diamine], dithiopyr [S,S-dimethyl 2-(difluoromethyl)-4-(2-methylpropyl)-6-(trifluoromethyl)-3,5-pyrldinecarbothioate], isoxaben [N-[3-(1-ethyl-l-methylpropyl)-5-isoxazolyl]-2,6-dimethoxybenzamide], metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-l-methylethyl) acetarnlde], oxadlazon I3-I2,4-dichloro-5-(l-methylethoxy)phenyl]-5-(1,1-dimethylethyl)-l,3,4-oxadiazol-2-(3H)-one], pendimethalin [N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine] and the combination of metolachlor plus atrazine. Acceptable ‘Floratam’ St. Augustinegrass color was noted following all treatments. Twelve to 24% of the stolons were unrooted 4 to 8 mo after application following treatment with 0kg a.i. ha−1 dithiopyr. Five to 22% of the stolons were unrooted 8 mo after treatment with isoxaben at 1.1 kg ha−1 and pendimethalin at 2.2 kg ha−1. Data collected after 8 mo showed stolon rooting to be similar to the untreated for all treatments. Turfgrass density was unaffected or slightly improved (≈25%) by herbicide treatment and was highest with oxadiazon, metolaehlor, and metolachlor plus atrazine treatments. Neither turfgrass tensile strength nor root dry weight was reduced 14 mo after treatment with any of the herbicides evaluated. Although shortterm (2 to 4 mo) negative effects followedithiopyr, isoxaben, and pendimethalin treatments, long-term (≥ 8 mo) effects were transient.
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