TITLE:
Post-Emergence Control of Windmillgrass (Chloris verticillata Nutt.) Using Selected Herbicides
AUTHORS:
Reid J. Smeda, Xi Xiong
KEYWORDS:
ACCase Inhibitor, HPPD Inhibitor, Triclopyr, Turfgrass Management
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.10 No.8,
August
21,
2019
ABSTRACT: Windmillgrass (Chloris
verticillata Nutt.) is spreading
from native areas, becoming problematic in established turf in Missouri, and
surrounding states. Limited information is available regarding post-emergence
(POST) control options for turf. The objective of this research was to assess
the visual and biomass response of windmillgrass to selected herbicides
approved for use in turf. In one study, a greenhouse experiment was conducted
with POST
application of seven selected herbicides, including dimethylamine salt of
quinclorac, fenoxaprop-P-ethyl, foramsulfuron, mesotrione, sulfentrazone, and
topramezone in a tank-mixture with triclopyr, as well as a pre-packed product
containing thiencarbazone-methyl, foramsulfuron, and halosulfuron-methyl. Under the same experimental
conditions, five additional treatments, including mesotrione or topramezone
applied at label-suggested rates alone or in combination with triclopyr, in
addition to triclopyr alone, were applied to a second study on tillering windmillgrass. At 4
weeks after treatment (WAT), only fenoxaprop-p-ethyl consistently resulted in a
complete control of windmillgrass. No measurable regrowth of plants was
observed two weeks following the initial collection of windmillgrass
aboveground biomass. In the second study, combinations of mesotrione and
topramezone with triclopyr resulted in 100% visual injury of windmillgrass at 4
WAT; mesotrione and topramezone alone only resulted in up to 66% visual injury.
Triclopyr alone resulted in 91% injury at 4 WAT. The greatest reduction of
windmillgrass biomass and least amount of regrowth resulted from mesotrione and
topramezone combinations with triclopyr. Control of windmillgrass is effective
with fenoxaprop-P-ethyl alone, but use of a 4-Hydroxyphenylpyruvate dioxygenase
(HPPD) inhibitor such as mesotrione and topramezone should include the addition
of triclopyr.