Selective Broadleaf Weed Control in Turfgrass with the BioherbicidesPhoma macrostomaand Thaxtomin A

2016 ◽  
Vol 30 (3) ◽  
pp. 688-700 ◽  
Author(s):  
Joseph C. Wolfe ◽  
Joseph C. Neal ◽  
Christopher D. Harlow

Both regulatory and consumer forces have increased the demand for biopesticides, particularly in amenity areas such as turfgrass. Unfortunately, few natural products are available for selective weed control in turfgrass. Two bioherbicides reported to control broadleaf weeds without injuring turfgrass arePhoma macrostomaand thaxtomin A. Field and container experiments were conducted to evaluate PRE and POST efficacy ofP. macrostomaand thaxtomin A on regionally important broadleaf weeds. In container experiments, PRE applications ofP. macrostomaprovided 65 to 100% control of dandelion, marsh yellowcress, and flexuous bittercress, equivalent to that of pendimethalin. Control of yellow woodsorrel, henbit, hairy galinsoga, common chickweed, or annual bluegrass was less than with pendimethalin. In contrast, POST applications did not control any species as well as an industry-standard synthetic auxin herbicide. PRE or POST applications of thaxtomin A controlled six of the eight species tested as well as the industry-standard PRE or POST herbicides. In field tests, overall PRE broadleaf weed control withP. macrostomaand thaxtomin A peaked 4 wk after treatment at 64 and 72%, respectively, and declined afterward, suggesting that these bioherbicides possess short residuals and therefore must be reapplied for season-long control. Overall POST broadleaf weed control usingP. macrostomaand thaxtomin A was only 41 and 25%, respectively. PRE followed by early-POST applications of thaxtomin A provided ≥ 86% henbit control. These results suggest that bothP. macrostomaand thaxtomin A are capable of controlling certain broadleaf weeds in turfgrass. However, both lack efficacy on some important weed species, particularly chickweed. Thaxtomin A efficacy on henbit was improved by increased dose and by PRE followed by early-POST applications.

2015 ◽  
Vol 95 (6) ◽  
pp. 1199-1204 ◽  
Author(s):  
Kimberly D. Belfry ◽  
Kristen E. McNaughton ◽  
Peter H. Sikkema

Belfry, K. D., McNaughton, K. E. and Sikkema, P. H. 2015. Weed control in soybean using pyroxasulfone and sulfentrazone. Can. J. Plant Sci. 95: 1199–1204. Pyroxasulfone and sulfentrazone are new herbicides currently being evaluated for weed control in soybean [Glycine max (L.) Merr.] in Ontario, Canada. Seven experiments were conducted over a 3-yr period (2011 to 2013) at Ridgetown and Exeter, Ontario, to evaluate weed management using pyroxasulfone, sulfentrazone and their tank-mixes relative to the industry standard, imazethapyr plus metribuzin. Tank-mixing pyroxasulfone and sulfentrazone provided up to 97, 46, 60, 100 and 71% control of common lambsquarters (Chenopodium album L.), common ragweed (Ambrosia artemisiifolia L.), green foxtail [Setaria viridis (L.) Beauv.], Powell amaranth [Amaranthus powellii (S.) Wats.] and velvetleaf (Abutilon theophrasti Medic.), respectively, at 2 wk after treatment. Control with pyroxasulfone and sulfentrazone was improved when tank-mixed, relative to application of each herbicide separately. Although control was variable across weed species, no difference in control was identified between pyroxasulfone plus sulfentrazone and imazethapyr plus metribuzin. Soybean yield was up to 2.7, 2.4 and 2.9 t ha−1 for pyroxasulfone, sulfentrazone and pyroxasulfone plus sulfentrazone application, yet imazethapyr plus metribuzin provided the highest yield (3.3 t ha−1). This research demonstrates that pyroxasulfone plus sulfentrazone may be used as a valuable weed control option in soybean; however, weed community composition may limit herbicidal utility.


2016 ◽  
Vol 30 (3) ◽  
pp. 733-742 ◽  
Author(s):  
Joseph C. Wolfe ◽  
Joseph C. Neal ◽  
Christopher D. Harlow ◽  
Travis W. Gannon

Recent trends favoring organic and sustainable turfgrass management practices have led to an increased desire for biologically based alternatives to traditional synthetic herbicides. Thaxtomin A, produced by the bacteriumStreptomyces scabies, has been reported to have PRE efficacy on broadleaf weeds, but efficacy of thaxtomin A on annual grassy weeds and safety to newly seeded cool-season turfgrasses have not been reported. Field experiments were conducted to evaluate PRE efficacy of thaxtomin A on smooth crabgrass and annual bluegrass. Monthly applications of thaxtomin A from April to July controlled smooth crabgrass through July but did not provide season-long control equivalent to an industry standard PRE herbicide. An initial application of thaxtomin A at 380 g ai ha−1followed by two applications at 190 or 380 g ha−1at 4-wk intervals provided season-long annual bluegrass control similar to an industry standard PRE herbicide. At 380 g ha−1, thaxtomin A reduced tall fescue and perennial ryegrass cover when applied 1 wk before seeding, at seeding, or 1 wk after seeding but was safe at other application timings. Up to three applications of thaxtomin A at 380 g ha−1at 4-wk intervals did not reduce perennial ryegrass cover. Applications to creeping bentgrass resulted in unacceptable turfgrass injury. These results suggest that thaxtomin A can suppress annual grassy weeds in tall fescue or perennial ryegrass turf when applied at least 2 wk before or after seeding. Furthermore, repeated applications of thaxtomin A can provide effective PRE control of annual bluegrass during overseeded perennial ryegrass establishment.


2012 ◽  
Vol 22 (6) ◽  
pp. 774-777 ◽  
Author(s):  
Gerald M. Henry ◽  
James T. Brosnan ◽  
Greg K. Breeden ◽  
Tyler Cooper ◽  
Leslie L. Beck ◽  
...  

Indaziflam is an alkylazine herbicide that controls winter and summer annual weeds in bermudagrass (Cynodon sp.) turf by inhibiting cellulose biosynthesis. Research was conducted in Tennessee and Texas during 2010 and 2011 to evaluate the effects of indaziflam applications on overseeded perennial ryegrass (Lolium perenne) establishment and summer annual weed control. In Texas, perennial ryegrass cover on plots treated with indaziflam at 0.75 and 1.0 oz/acre measured 37% to 48% compared with 88% for the untreated control 257 days after initial treatment (DAIT). Perennial ryegrass cover following applications of indaziflam at 0.5 oz/acre measured 84% 257 DAIT and did not differ from the untreated control on any evaluation date. Inconsistent responses in crabgrass (Digitaria sp.) control with indaziflam at 0.5 oz/acre were observed in Tennessee and Texas. However, control was similar to the 0.75-oz/acre rate and prodiamine at 7.8 oz/acre at each location. A September application of indaziflam at 0.75 oz/acre followed by a sequential treatment at 0.5 oz/acre in March of the following year provided >90% control by June 2011. Indaziflam application regimes of this nature would allow for successful fall overseeding of perennial ryegrass every two years and control winter annual weed species such as annual bluegrass (Poa annua).


2004 ◽  
Vol 18 (4) ◽  
pp. 887-892 ◽  
Author(s):  
Ryan F. Hasty ◽  
Christy L. Sprague ◽  
Aaron G. Hager

Field studies were conducted during 1999 and 2000 to compare weed control after fall and early-preplant (EPP) herbicide applications in no-till soybean. Three residual treatments (chlorimuron plus metribuzin, chlorimuron plus sulfentrazone, and metribuzin) were applied at two rates and timings (fall and 30 d EPP) either alone or in combination with glyphosate and 2,4-D. The addition of glyphosate and 2,4-D to fall-applied residual herbicides significantly increased control of common chickweed, annual bluegrass, cressleaf groundsel, and shepherd's-purse. The effect of application rate on weed control was species dependent. Fall-applied residual herbicides were comparable with EPP treatments with respect to winter annual weed control; however, at planting control of summer annual weed species with fall treatments was less consistent compared with EPP residual herbicides.


2006 ◽  
Vol 24 (2) ◽  
pp. 84-90 ◽  
Author(s):  
L.T. Case ◽  
H.M. Mathers

Abstract Weed control is the largest expense faced in the nursery and landscape industries. Nursery growers spend $967 to $2,228/A, depending on species, for supplemental hand weeding in addition to three to four yearly herbicide applications. Herbicide-treated mulches have utility in addressing many current nursery/landscape weed control issues such as non-target herbicide losses, leaching and off-site herbicide movement, and reduction of weed control costs. The objectives of this study were to compare seven types of mulches, including Douglas fir nuggets, pine nuggets, shredded hardwood, shredded Cypress, PennMulch™, rice hulls, and cocoa shells sprayed with Surflan [aqueous solution (AS) (oryzalin) at 1.12 (0.5×) and 2.24 (1×) kg ai/ha (1.0 and 2.0 lb ai/A)] and SureGuard [(water dispersible granular (WDG) (flumioxazin) at 0.19 (0.5×) and 0.38 (1×) kg ai/ha (0.17 and 0.34 lb ai/A)] to determine efficacy on common chickweed (Stellaria media), annual bluegrass (Poa annua) and spotted spurge (Chamaesyce humistrata) and phytotoxicity to Golden vicary privet (Ligustrum × vicaryi), creeping juniper (Juniperus horizontalis ‘P.C. Youngstown’), and wintergreen boxwood (Buxusmicrophylla ‘Wintergreen’) at 45 and 115 days after treatment (DAT). The herbicide-treated mulches were compared to untreated mulches, over-the-top sprays of the herbicides and a combination spray of Surflan + SureGuard each applied at the 1× rate, described above, an industry-standard granular formulation Rout (oxyfluorfen + oryzalin) at 3.41 kg ai/ha (3.0 lb ai/A), an industry standard nonchemical alternative Geodisc™, and an untreated control. The experiment was conducted in 2001 and repeated in 2002. In 2001, 17 of 43 treatments provided commercially acceptable visual ratings at 45 DAT; 14 were herbicide treated mulches. Four of five treatments in 2001 providing acceptable control at 115 DAT were herbicide treated mulches. In 2002, three treatments providing commercially acceptable control at 45 DAT were: PennMulch™ + 0.5 × Surflan, PennMulch™ + SureGuard, and Rout. Rout was the only treatment providing commercially acceptable control at 115 DAT in 2002. Golden vicary privet exhibited the greatest phytotoxicity in both years. In 2001-2002, the over-the-top sprays of Surflan + SureGuard were the most phytotoxic treatments to Golden vicary privet when averaged across 45 and 115 DAT. The data indicated a significant herbicide × mulch interaction and that some combinations, such as hardwood + SureGuard or pine nuggets + SureGuard, increased and extended efficacy and reduced phytotoxicity versus mulches or herbicides applied alone.


Weed Science ◽  
2010 ◽  
Vol 58 (3) ◽  
pp. 310-316 ◽  
Author(s):  
K. Steenwerth ◽  
K. Baumgartner ◽  
K. Belina ◽  
L. Veilleux

This research compared effects of the weed control practice, soil cultivation, and the conventional practice, glyphosate application on weed seedbank, in a vineyard system. The experiment was conducted in a commercial wine-grape vineyard in the Napa Valley of northern California from 2003 to 2005. The annual treatments were “winter–spring glyphosate,” “spring cultivation,” “fall–spring cultivation,” and “fall cultivation–spring glyphosate,” and were applied “in-row,” under the vine. Composition of the weed seedbank collected in 2002 before treatment establishment did not differ among treatments. After 3 yr of weed treatments, detrended correspondence analysis indicated that the composition of spring cultivation and winter–spring glyphosate tended to differ from each other, but the remaining two treatments showed little differentiation. As determined by linear discriminant analysis, the specific weed species were associated with seedbanks of certain treatments. These were Carolina geranium, annual bluegrass, brome grasses, California burclover, and scarlet pimpernel, which do not pose problems with regard to physical aspects of grape production. Although ‘Zorro’ rattail fescue was ubiquitous among treatments, its distribution between depths in the cultivated treatments indicated that tillage provided some homogenization of seedbank along the vertical soil profile. The seedlings from the seedbank study were not congruent with those measured aboveground in the field, suggesting that both treatment and microclimatic effects in the field may have influenced germination, and thus, aboveground composition.


2020 ◽  
Vol 57 (3) ◽  
pp. 199-210
Author(s):  
Rajib Kundu ◽  
Mousumi Mondal ◽  
Sourav Garai ◽  
Ramyajit Mondal ◽  
Ratneswar Poddar

Field experiments were conducted at research farm of Bidhan Chandra Krishi Viswavidyalaya, Kalyani, West Bengal, India (22°97' N latitude and 88°44' E longitude, 9.75 m above mean sea level) under natural weed infestations in boro season rice (nursery bed as well as main field) during 2017-18 and 2018-19 to evaluate the herbicidal effects on weed floras, yield, non-target soil organisms to optimize the herbicide use for sustainable rice-production. Seven weed control treatments including three doses of bispyribac-sodium 10% SC (150,200, and 250 ml ha-1), two doses of fenoxaprop-p-ethyl 9.3% EC (500 and 625 ml ha-1), one weed free and weedy check were laid out in a randomized complete block design, replicated thrice. Among the tested herbicides, bispyribac-sodium with its highest dose (250 ml ha-1) resulted in maximum weed control efficiency, treatment efficiency index and crop resistance index irrespective of weed species and dates of observation in both nursery as well as main field. Similar treatment also revealed maximum grain yield (5.20 t ha-1), which was 38.38% higher than control, closely followed by Fenoxaprop-p-ethyl (625 ml ha-1) had high efficacy against grasses, sedge and broadleaf weed flora. Maximum net return (Rs. 48765 ha-1) and benefit cost ratio (1.72) were obtained from the treatment which received bispyribac-sodium @ 250 ml ha-1. Based on overall performance, the bispyribac-sodium (250 ml ha-1) may be considered as the best herbicide treatment for weed management in transplanted rice as well as nursery bed.


2021 ◽  
pp. 1-28
Author(s):  
Nicholas T. Basinger ◽  
Nicholas S. Hill

Abstract With the increasing focus on herbicide-resistant weeds and the lack of introduction of new modes of action, many producers have turned to annual cover crops as a tool for reducing weed populations. Recent studies have suggested that perennial cover crops such as white clover could be used as living mulch. However, white clover is slow to establish and is susceptible to competition from winter weeds. Therefore, the objective of this study was to determine clover tolerance and weed control in established stands of white clover to several herbicides. Studies were conducted in the fall and winter of 2018 to 2019 and 2019 to 2020 at the J. Phil Campbell Research and Education Center in Watkinsville, GA, and the Southeast Georgia Research and Education Center in Midville, GA. POST applications of imazethapyr, bentazon, or flumetsulam at low and high rates, or in combination with 2,4-D and 2,4-DB, were applied when clover reached 2 to 3 trifoliate stage. Six weeks after the initial POST application, a sequential application of bentazon and flumetsulam individually, and combinations of 2,4-D, 2,4-DB, and flumetsulam were applied over designated plots. Clover biomass was similar across all treatments except where it was reduced by sequential applications of 2,4-D + 2,4-DB + flumetsulam in the 2019 to 2020 season indicating that most treatments were safe for use on establishing living mulch clover. A single application of flumetsulam at the low rate or a single application of 2,4-D + 2,4-DB provided the greatest control of all weed species while minimizing clover injury when compared to the non-treated check. These herbicide options allow for control of problematic winter weeds during clover establishment, maximizing clover biomass and limiting canopy gaps that would allow for summer weed emergence.


Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1326
Author(s):  
Calvin F. Glaspie ◽  
Eric A. L. Jones ◽  
Donald Penner ◽  
John A. Pawlak ◽  
Wesley J. Everman

Greenhouse studies were conducted to evaluate the effects of soil organic matter content and soil pH on initial and residual weed control with flumioxazin by planting selected weed species in various lab-made and field soils. Initial control was determined by planting weed seeds into various lab-made and field soils treated with flumioxazin (71 g ha−1). Seeds of Echinochloa crus-galli (barnyard grass), Setaria faberi (giant foxtail), Amaranthus retroflexus (redroot pigweed), and Abutilon theophrasti (velvetleaf) were incorporated into the top 1.3 cm of each soil at a density of 100 seeds per pot, respectively. Emerged plants were counted and removed in both treated and non-treated pots two weeks after planting and each following week for six weeks. Flumioxazin control was evaluated by calculating percent emergence of weeds in treated soils compared to the emergence of weeds in non-treated soils. Clay content was not found to affect initial flumioxazin control of any tested weed species. Control of A. theophrasti, E. crus-galli, and S. faberi was reduced as soil organic matter content increased. The control of A. retroflexus was not affected by organic matter. Soil pH below 6 reduced flumioxazin control of A. theophrasti, and S. faberi but did not affect the control of A. retroflexus and E. crus-galli. Flumioxazin residual control was determined by planting selected weed species in various lab-made and field soils 0, 2, 4, 6, and 8 weeks after treatment. Eight weeks after treatment, flumioxazin gave 0% control of A. theophrasti and S. faberi in all soils tested. Control of A. retroflexus and Chenopodium album (common lambsquarters) was 100% for the duration of the experiment, except when soil organic matter content was greater than 3% or the soil pH 7. Eight weeks after treatment, 0% control was only observed for common A. retroflexus and C. album in organic soil (soil organic matter > 80%) or when soil pH was above 7. Control of A. theophrasti and S. faberi decreased as soil organic matter content and soil pH increased. Similar results were observed when comparing lab-made soils to field soils; however, differences in control were observed between lab-made organic matter soils and field organic matter soils. Results indicate that flumioxazin can provide control ranging from 75–100% for two to six weeks on common weed species.


1996 ◽  
Vol 10 (2) ◽  
pp. 253-257 ◽  
Author(s):  
Joan A. Dusky ◽  
William M. Stall

Imazethapyr was evaluated PRE and POST in five lettuce types and chicory under Florida field conditions. The relative sensitivity of leafy crop vigor (most sensitive to most tolerant) to imazethapyr PRE, based on 20% inhibition determined using regression analysis, was as follows: Boston > bibb > crisphead > romaine > leaf > escarole > endive. Leafy crop injury increased as the rate of imazethapyr applied POST increased, with all leafy crops responding in a similar manner. Surfactant addition increased imazethapyr phytotoxicity. Imazethapyr PRE treatments at 0.067 kg ai/ha provided greater than 80% control of livid amaranth, common purslane, flatsedge, and common lambsquarters. Imazethapyr POST at 0.067 kg/ha, with surfactant provided control greater than 85% of all weed species. Greater than 85% spiny amaranth control was provided by imazethapyr POST at 0.017 kg/ha. Use of surfactant with imazethapyr did not improve spiny amaranth control over imazethapyr with no surfactant. POST treatments did not decrease leafy crop yield compared with the hand-weeded check. Imazethapyr applied PRE reduced crop yield compared to the POST treatments and the hand-weeded control.


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