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Invasive Plant Science and
Management
www.cambridge.org/inp
Note
Cite this article: Yu P, Marble SC, and
Minogue P (2022). Herbicide selection for
controlling Tahitian bridal veil (Gibasis
pellucida). Invasive Plant Sci. Manag.
doi: 10.1017/inp.2022.25
Received: 12 July 2022
Revised: 21 September 2022
Accepted: 14 October 2022
Associate Editor:
James K. Leary, University of Florida
Keywords:
2,4-D; aminopyralid; glufosinate; invasive plant;
metsulfuron-methyl; triclopyr
Author for correspondence:
Stephen Christopher Marble, Department of
Environmental Horticulture, University of
Florida, Mid-Florida Research and Education
Center, Apopka, FL 32703.
(Email: marblesc@ufl.edu)
© The Author(s), 2022. Published by Cambridge
University Press on behalf of the Weed Science
Society of America. This is an Open Access
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licenses/by-nc-sa/4.0/), which permits non-
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Herbicide selection for controlling Tahitian
bridal veil (Gibasis pellucida)
Ping Yu1, S. Christopher Marble2and Patrick Minogue3
1Assistant Professor, Department of Horticulture, University of Georgia, Griffin, GA, USA; Former Postdoctoral
Research Associate, Department of Environmental Horticulture, Mid-Florida Research and Education Center,
University of Florida, Apopka, FL, USA; 2Associate Professor, Department of Environmental Horticulture,
Mid-Florida Research and Education Center, University of Florida, Apopka, FL, USA and 3Associate Professor,
School of Forest, Fisheries, and Geomatics Sciences, North Florida Research and Education Center, University of
Florida, Quincy, FL, USA
Abstract
Tahitian bridal veil [Gibasis pellucida (M. Martens & Galeotti) D.R. Hunt], a Central and South
America native plant that is often confused with another more well-known invasive plant, small
leaf spiderwort (Tradescantia fluminensis Vell.), has become invasive in natural areas through-
out Florida. However, very little is known regarding herbicide control or other methods.
To begin the process of developing herbicide recommendations for land managers who are
working to control G. pellucida, multiple postemergence herbicides were screened for efficacy
in a shaded greenhouse to determine active ingredients and/or combinations that warrant
further investigation under field conditions. Nine different herbicides or combinations, includ-
ing glyphosate, triclopyr acid, 2,4-D þtriclopyr, aminopyralid, 2,4-D, triclopyr amine, metsul-
furon-methyl, fluroxypyr, and glufosinate, were applied at standard label rates and compared
with a nontreated control group. Visual control ratings were taken at 2, 4, and 8 wk after treat-
ment (WAT), and shoot dry weights were determined at trial conclusion (8 WAT). Data
showed glufosinate and triclopyr (acid and amine) provided the highest level of control, as
evidenced by control ratings (100% or complete control) and shoot fresh weight reduction,
followed by 2,4-D þtriclopyr (~70%) and fluroxypyr (~50% control). Metsulfuron-methyl
and 2,4-D provided the lowest level of control, with results similar to those for nontreated plants
on most evaluation dates.
Introduction
Tahitian bridal veil [Gibasis pellucida (M. Martens & Galeotti) D.R. Hunt; Commelinaceae]
is native to Mexico and parts of Central and South America. Originally introduced to the
United States as an ornamental plant (Fantz and Nelson 1995), it soon naturalized and has
become invasive, specifically in Texas (Rosen and Faden 2005) and Florida, where it has
been vouchered in 12 counties across the state (Wunderlin et al. 2022). While not classified
as a category 1 or 2 invasive by the Florida Invasive Species Council (FISC), it is a species
of increasing concern with the Florida Fish and Wildlife Conservation Commission (S Yuan,
personal communication) and other land management groups (FISC 2019)andhas
shown the propensity for becoming highly invasive in previous examinations of the
Commelinaceae family (Moriuchi 2006).
Gibasis pellucida spreads primarily vegetatively by rooting at the nodes along decum-
bently growing stems. Seeds have been found on plants, but previous studies have noted
that it is usually self-incompatible (Hunt 1986). Leaves are asymmetrical, 1- to 5-cm long
and up to 3-cm wide and typically dark green in color on the surface to reddish-purple
underneath, and stems are 1 mm in diameter (Fantz and Nelson 1995). Observations of
spread and invasive potential in Florida are similar to those reported in Texas, where
G. pellucida establishes (escapes from cultivation) and spreads rapidly in riparian or dis-
turbed areas under broken to closed-canopy forests (Rosen and Faden 2005). Although
G. pellucida has not been documented altering native plant communities on a large scale,
there is reason for concern due to its similarity in biology and growth with another invasive
Commelinaceae member, small leaf spiderwort (Tradescantia fluminensis Vell.) (Figure 1).
Tradescantia fluminensis is currently classified as a Category I invasive by the FISC based on
documented ecological damage and displacement of native species (FISC 2019). While
G. pellucida is not officially classified as invasive, in studies of invasive Commelinaceae genera
potential, it was estimated to have a higher rate of spread compared with T. fluminensis
(Moriuchi 2006). Superficially, both plants are very similar in appearance and growth habit,
especially when not in flower, possibly leading to misidentification in field. While detailed
differences between the two species have been summarized previously (Fantz and Nelson
https://doi.org/10.1017/inp.2022.25 Published online by Cambridge University Press
1995; Seitz and Clark 2016), the most easily observable difference
in the field are stipitate cymes with long peduncles (12- to 17-mm
long) and pedicels (7- to 14-mm long) of G. pellucida (Fantz and
Nelson 2005) compared with sessile cymes of T. fluminensis (Fantz
and Nelson 1995; Seitz and Clark 2016).
Due to the widespread impacts of T. fluminensis in New
Zealand, Brazil, Florida, and other subtropical regions, many stud-
ies have evaluated management options for it, including herbicide
and cultural options such as shading and manual removal. Overall,
herbicides have been reported to be the most effective and only
feasible option on a large scale (Standish 2002), with triclopyr
reported as the most consistently effective herbicide for T. flumi-
nensis. Triclopyr ester, amine, and choline have all been found to
consistently provide 90% control or greater in multiple experi-
ments (Brown and Brown 2015; Hurrell et al. 2008,2009; Lusk
et al. 2012; Marble and Chandler 2021) when applied at labeled
rates. Glyphosate has also been evaluated extensively in multiple
studies, with results ranging from ~30% to 60% control depending
on rate and location (Brown and Brown 2015; Marble and
Chandler 2021), but multiple applications have typically
been needed to provide optimal control (McCluggage 1998).
Glufosinate and fluroxypyr have been successful in limited testing
(Marble and Chandler 2021), while metsulfuron-methyl, sulfentra-
zone, clopyralid, aminopyralid, and 2,4-D have generally been
found to be ineffective on mature populations (Kelly and
Skipworth 1984; Marble and Chandler 2021; McCluggage 1998).
Whiletherearenumerousreportsofherbicideefficacyon
T. fluminensis, there are no documented herbicide efficacy data
for G. pellucida. As these species can be easily misidentified due
to morphological similarities and tend to invade similar habi-
tats, management recommendations are now needed to help
prevent further spread and ecological impact. Therefore, the
objective of this research was to evaluate efficacy of postemer-
gence herbicides for control of G. pellucida in small-scale pot
studies using herbicides previously evaluated for T. fluminensis.
The overall objective of this work was to identify herbicide active
ingredients that show promise as control options to support
future field testing in areas where this species is becoming
increasingly more common.
Materials and Methods
Studies were conducted in a shade house (60% reduction of ambi-
ent light) located at the Mid-Florida Research and Education
Center, University of Florida, in Apopka, FL, USA. Gibasis pellu-
cida cuttings were collected from a local park (Big Tree Park,
Longwood, FL, USA, 28.7214°N, 81.3306°W) and rooted into nurs-
ery pots (top diameter: 16.4 cm, bottom diameter: 12.5 cm; depth:
17.5 cm; volume: 2.84 L) filled with a soilless substrate composed of
pine bark (Southeast Soils, Okahumpka, FL, USA; pine bark:
Florida peat:sand =9:1:1 v:v:v) with four terminal stems per pot
on October 1, 2021. At 2 wk after sticking, each container was
top-dressed with 11 g of control release fertilizer [17 N-2.2
P-9.1 K, Osmocote®Blend 17-5-11, 8 to 9 month; ICL Specialty
Fertilizers, Dublin, OH, USA), which represented the manufac-
turer’s recommended low rate.
On December 6, 2021 (clear skies, 23 C, 76% relative humidity,
calm winds), all plants were removed from the shade house and
placed onto a gravel area outdoors, where selected herbicides
(Table 1) were applied using a CO
2
backpack sprayer calibrated
to deliver 234 L ha−1using a TeeJet®8004 flat-fan nozzle (TeeJet
Technologies, Wheaton, IL, USA) at 241 kPa. A non-ionic surfac-
tant (AirCover, Winfield Solutions, St Paul, MN, USA) was added
at a 0.5% v:v rate to treatments including 2,4-D, triclopyr (acid and
amine), metsulfuron-methyl, and fluroxypyr based on manufac-
turers’recommendations. After 24 h of herbicide treatment, plants
were moved back inside the shade house, where they remained for
the duration of the experiment. At the time of treatment, each pot
contained four individual fully rooted plants that were approxi-
mately 40- to 50-cm in length. Plants were irrigated 1.3 cm daily
with overhead irrigation (Xcel-Wobbler™, Senninger Irrigation,
Clermont, FL, USA) via two irrigation cycles (7:00 AM and 2:45
PM) throughout the experiment. The study was repeated following
the same methodology and timeline on December 15, 2021 (over-
cast, 24 C, 78% relative humidity, calm winds).
At 2 wk after herbicide treatment (2 WAT), plants were rated
visually on a 0 to 100 rating scale (Figure 2), with 0 indicating no
control (no damage) and 100 representing complete control (100%
damage). Subsequent visual ratings were taken at 4 WAT and 8
WAT. At the conclusion of the experiment at 8 WAT, plant shoots
were clipped at the soil line, and shoot dry weight was determined
after placing shoots in a forced-air oven at 60 C for 7 d. The experi-
ment was arranged as a randomized complete block design with
eight replications for each treatment. The non–herbicide treated
plants served as the control group.
Statistical Analysis
The data from the two experimental runs were combined, as there
were no experimental run by treatment interactions. The signifi-
cance of treatment effects was determined by ANOVA using R
program software v. 3.5.1 (R Core Team 2018). Post hoc multiple
comparisons were made using the Holm-Bonferroni method to
adjust P-values for multiple comparisons. In all cases differences
were considered significant at P ≤0.05.
Results and Discussion
Glufosinate, triclopyr acid, and triclopyr amine provided the high-
est level of control over the course of the experiment (Table 2). All
three herbicides provided increased visual control values on sub-
sequent evaluations, reaching 100% by 8 WAT. A high control rat-
ing for glufosinate was not surprising, as it tends to result in more
Management Implications
Gibasis pellucida (Tahitian bridal veil) is an emerging invasive
plant species of concern in Florida and Texas, but there are no pre-
vious reports of effective herbicide management options. Nine herbi-
cides and combinations were evaluated for postemergence control of
G. pellucida grown in pots in a shaded greenhouse. Results showed
that glufosinate and triclopyr (acid and amine formulations evalu-
ated separately) provided 100% control, followed by triclopyr þ
2,4-D with 70% control and fluroxypyr with 50% control, as
evidenced by visual control ratings and dry shoot weight.
Aminopyralid, 2,4-D, and metsulfuron-methyl provided low or no
control in comparison with a nontreated control group. While fur-
ther work is needed to evaluate these and other herbicides under field
conditions, data reported here are noteworthy, as this is the first
report on herbicide selection for G. pellucida control. Results also
suggest that based on previous reports, the same herbicides that have
shown high efficacy for Tradescantia fluminensis (small leaf spider-
wort) would also be effective for G. pellucida management.
2 Yu et al.: G. pellucida herbicide selection
https://doi.org/10.1017/inp.2022.25 Published online by Cambridge University Press
rapid symptomology compared with triclopyr (Shaner 2014). In
contrast, 2,4-D and metsulfuron-methyl had rating values similar
to those of the nontreated control, which remained very low (rang-
ing from 0 to 10) throughout the trial. Aminopyralid and glyph-
osate provided some level of control, with ratings ranging from
12% to 24%. Conversely, fluroxypyr and triclopyr þ2,4-D pro-
duced a marginal effect on G. pellucida, resulting in rating values
ranging from 48% to 71%. Moreover, visually estimated control
resulting from fluroxypyr and triclopyr þ2,4-D increased from
2 WAT to 4 WAT but decreased by 8 WAT, indicating recovery
in these treatments.
When biomass was evaluated, 2,4-D (91.64 g) and metsulfuron-
methyl (125.63 g) resulted in significantly greater biomass than
other herbicide treatments, but still provided a minor reduction
in biomass in comparison with the nontreated control group.
No statistically significant differences were shown between the
other treatments, with the exception of plants treated with amino-
pyralid (27.66 g) having greater biomass than those treated with
triclopyr amine (3.53 g), glufosinate (4.96 g), and triclopyr acid
(5.06 g), fluroxypyr (8.93 g), and 2,4-D þtriclopyr (11.38 g).
Results from visual ratings and biomass measures indicated
that triclopyr (both amine and acid formulations) and glufosi-
nate would likely be effective options for G. pellucida control, as
100% control was achieved in these shade-house evaluations.
However, research under field conditions would be needed
for confirmation (Riemens et al. 2008). Fluroxypyr, glyphosate,
and 2,4-D þtriclopyr provided only marginal visual control, but
based on biomass data could potentially be options at higher
doses, when used as a sequential application to another herbi-
cide, or when infestations are not severe. As G. pellucida has
a spreading growth habit, it is likely that, similar to T. fluminen-
sis, multiple applications will be needed, as complete control is
often not achieved (Marble and Chandler 2021). Thus, having
different herbicide options available, even if efficacy is not ideal,
would be important to prevent exceeding maximum annual
doses. No dose–response curves have been established for G.
pellucida,asthisisthefirstreportofefficacytoourknowledge.
Based on our results with the two triclopyr treatments alone (3.4
kg ae ha−1) compared with the lower control observed with the
2,4-D þtriclopyr treatment (1 kg ae ha−1triclopyr), it is evident
that a triclopyr rate of greater than 1 kg ae ha−1would likely be
needed for effective control. Metsulfuron-methyl and 2,4-D
provided poor control, and based on this study, use at the rates
evaluated would not be recommended.
When comparing the herbicides used in this study and herbi-
cides previously evaluated for T. fluminensis control, there are
both similarities and differences. Like T. fluminensis, triclopyr pre-
sented as the most effective herbicide to control G. pellucida.
Marble and Chandler (2021) reported a >80% reduction in
T. fluminensis biomass when treated with triclopyr (amine, ester,
or choline) at rates as low as 1.7 kg ae ha−1; thus, further testing is
needed to determine the optimal rate for G. pellucida. Also, 2,4-D
Figure 1. The flower (left) and whole plant (middle) of Gibasis pellucida compared with Tradescantia fluminensis (right).
Table 1. Herbicides evaluated for postemergence control of Gibasis pellucida.
Herbicide Trade name RateaManufacturer
—kg ha−1—
2,4-Db2,4-D amine 4.3 Southern Agricultural Insecticides, Inc., Rubonia, FL, USA
2,4-D þtriclopyr amine AquaSweep™2.6 þ1.0 Nufarm Americas Inc., Alsip, IL, USA
Aminopyralid Milestone®0.12 Corteva Agriscience, Indianapolis, IN, USA
FluroxypyrbVista®XRT 0.28 Corteva Agriscience, Indianapolis, IN, USA
Glufosinate Finale®1.1 BASF Corporation, Research Triangle Park, NC, USA
Glyphosate Roundup Custom®3.4 Bayer Environmental Science, Research Triangle Park, NC, USA
Metsulfuron-methylbEscort®XP 0.04 Bayer Environmental Science, Research Triangle Park, NC, USA
Triclopyr acidbTrycera®3.4 Helena Agri-Enterprises, LLC, Collierville, TN, USA
Triclopyr aminebGarlon®3A 3.4 Corteva Agriscience, Indianapolis, IN, USA
aRates are given in kg ae ha−1, with the exception of aminopyralid, metsulfuron-methyl, and glufosinate, which are presented in kg ai ha−1.
bHerbicides were applied with the addition of a non-ionic surfactant (AirCover, Winfield Solutions, St Paul, MN, USA) at a 0.5% v/v rate based on the manufacturers’recommendations.
Invasive Plant Science and Management 3
https://doi.org/10.1017/inp.2022.25 Published online by Cambridge University Press
and metsulfuron-methyl performed poorly in controlling both
T. fluminensis and G. pellucida. Both Hurrell et al. (2008) and
Marble and Chandler (2021) showed satisfactory control of
T. fluminensis with fluroxypyr, and this is in agreement with
results for G. pellucida in our study. Glufosinate also provided
effective control of both species, at least in greenhouse evalua-
tions (Marble and Chandler 2021). Glyphosate, on the other
hand, showed some marginal effects on G. pellucida,andmixed
results have been reported for T. fluminensis. McCluggage
(1998) and Brown and Brown (2015) showed high levels of T. flu-
minensis control with glyphosate, but studies conducted by Kelly
and Skipworth (1984) and Marble and Chandler (2021) showed
only marginal control and the need for multiple applications.
Overall, data presented here indicate that triclopyr (amine or
acid) and glufosinate have a high degree of efficacy on G. pellucida,
at least under greenhouse-like conditions. Based on this work, the
same general treatment approach that is recommended for T. flu-
minensis will potentially be effective for G. pellucida, but further
research is needed to evaluate both these herbicides for G. pellucida
control under field conditions on mature, densely growing popu-
lations. Work is also needed to evaluate the efficacy of selected her-
bicides on T. fluminensis and G. pellucida in a side-by-side
comparison, as results have been variable with some herbicides
based on time of year, environment, and growth stage.
Acknowledgments. The authors wish to thank Samantha Yuan and the
Florida Fish and Wildlife Conservation Commission for supporting and
sponsoring this research and bringing our attention to this emerging invasive
plant species of concern in Florida. No conflicts of interest have been
declared.
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—kg ha−1——% (SE)c——g—
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