Do applications of systemic herbicides when green fruit are present prevent seed production or viability of Alliaria petiolata (garlic mustard)?

Garlic mustard [Alliaria petiolata (M. Bieb.) Cavara & Grande] is a biennial invasive plant commonly found in the northeastern and midwestern United States. Although it is not recommended to apply herbicides after flowering, land managers frequently desire to conduct management during this timing. We applied glyphosate and triclopyr (3% v/v and 1% v/v using 31.8% and 39.8% acid equivalent formulations, respectively) postemergence to established, second-year A. petiolata populations at three locations when petals were dehiscing, and evaluated control, seed production and seed viability. Postemergence glyphosate applications at this timing provided 100% control of A. petiolata by 4 weeks after treatment at all locations whereas triclopyr efficacy was variable, providing 38-62% control. Seed production was only reduced at one location, with similar results regardless of treatment. Percent seed viability was also reduced, and when combined with reductions in seed production, we found a 71-99% reduction in number of viable seed produced plant-1 regardless of treatment. While applications did not eliminate viable seed production, our findings indicate that glyphosate and triclopyr applied while petals were dehiscing is a viable alternative to cutting or hand-pulling at this timing as it substantially decreased viable A. petiolata seed production. Management Implications Postemergence glyphosate and triclopyr applications in the early spring to rosettes are standard treatments used to manage A. petiolata. However, weather and other priorities limit the window for management, forcing field practitioners to utilize more labor-intensive methods such as hand-pulling. It is not known how late in the development of A. petiolata these herbicides can be applied to prevent viable seed production. Since prevention of soil seedbank replenishment is a key management factor for effective long-term control of biennial invasive species, we hypothesized late spring foliar herbicide applications to second year A. petiolata plants when flower petals were dehiscing could be an effective management tool if seed production or viability is eliminated. Our study indicated that glyphosate applications at this timing provided 100% control of A. petiolata plants by 4 weeks after treatment at all locations, whereas triclopyr efficacy was inconsistent. Although both glyphosate and triclopyr decreased viable seed production to nearly zero at one of our three study locations, the same treatments produced significant amounts of viable seed at the other two locations. Our findings suggest late spring glyphosate and triclopyr applications should not be recommended over early spring applications to rosettes for A. petiolata management, as our late spring application timing did not prevent viable seed production, and may require multiple years of implementation to eradicate populations. Nonetheless, this application timing holds value in areas devoid of desirable understory vegetation compared to no management practices or mechanical management options including hand-pulling when fruit are present, as overall viable seed production was reduced to similar levels as these treatments.

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Potential Role of Sequential Glufosinate and Foramsulfuron Applications for Management of Fescues (Festucaspp.) in Wild Blueberry

Weed Technology ◽

10.1614/wt-d-16-00086.1 ◽

2017 ◽

Vol 31 (1) ◽

pp. 100-110 ◽

Cited By ~ 4

Author(s):

Scott N. White ◽

Shanthanu Krishna Kumar

Keyword(s):

Field Study ◽

Seed Production ◽

Potential Role ◽

Seedling Recruitment ◽

Seedling Emergence ◽

Seed Viability ◽

Early Spring ◽

Seedling Mortality ◽

Wild Blueberry

Sheep and hair fescue are perennial, tuft forming grasses that spread by seed and form dense sods in wild blueberry fields. These sods compete with the crop for resources and hinder harvest. Field and greenhouse studies were conducted in 2015 to evaluate 1) the effect of sequential glufosinate and foramsulfuron applications on suppression of fescues in the greenhouse and field, and 2) efficacy of glufosinate and foramsulfuron on fescue seedlings when applied at 2, 4, 6, and 8 wk after seedling emergence in the greenhouse. Glufosinate applications at 750 and 1,005 g ai ha−1followed by foramsulfuron application at 35 g ai ha−1reduced fescue leaf number and biomass relative to foramsulfuron application alone in the greenhouse. In the field study, fescue flowering tuft density, tuft inflorescence height, seed production, and seed viability were reduced by foramsulfuron alone, but there was a trend towards lower seed production and tuft height when fescues were treated with glufosinate at 1,005 g ha−1followed by foramsulfuron. Foramsulfuron caused low seedling mortality at all application timings evaluated, but glufosinate caused >90% mortality in seedlings when applied at 2, 4, 6, or 8 wk after seedling emergence. Our results suggest that sequential applications of these herbicides are less effective under field conditions relative to results obtained in the greenhouse, though burndown glufosinate applications may have a role in reducing fescue seedling recruitment. Additional research should be conducted to determine the effect of early spring and autumn glufosinate applications on fescue seedling recruitment and suppression of established fescue tufts with subsequent foramsulfuron applications.

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Flowering, Fecundity, Seed Germination, and Seed Viability of Viburnum opulus L. Cultivars

Journal of Environmental Horticulture ◽

10.24266/0738-2898-27.1.31 ◽

2009 ◽

Vol 27 (1) ◽

pp. 31-36

Author(s):

Janine R. Conklin ◽

James C. Sellmer

Keyword(s):

Seed Germination ◽

Seed Production ◽

Seed Viability ◽

Biological Traits ◽

Limited Information ◽

Viable Seed ◽

Invasive Potential ◽

Short Term ◽

Viburnum Opulus ◽

Tetrazolium Test

Abstract Mature specimens of Viburnum opulus and cultivars ‘Leonard's Dwarf’ and ‘Roseum’ were assessed over 2 years for flower and seed production, seed germination, and seed viability as determined by a tetrazolium test to understand their invasive potential. ‘Aureum’, ‘Compactum’, ‘Losely's Compact’, ‘Nanum’, and ‘Xanthocarpum’ were also tested for germination and viability of seeds. Cultivars differed in flower and seed production, seed germination, and seed viability. ‘Roseum’ prolifically produced highly viable seed that germinated at moderate rates under greenhouse conditions (8,354, 100%, and 73%, respectively). Viburnum opulus and ‘Leonard's Dwarf’ produced fewer viable seed which showed moderate to low germination rates (609, 100%, and 53%; 712, 100%, and 5%, respectively). ‘Aureum’ and ‘Xanthocarpum’ seeds germinated at moderate rates (55 and 25%, respectively) and were highly viable (100%). ‘Compactum’, ‘Losely's Compact’, and ‘Nanum’ germinated at low rates or failed to germinate (0, 0, and 5%, respectively), yet seeds were moderately viable (37, 65, and 55%, respectively). Seeds of all cultivars germinated at low rates or failed to germinate at both outdoor sites (0 to 5%) which suggests these plants may be weakly invasive. Short-term studies on biological traits such as these provide only limited information to assess the invasive potential of cultivars.

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Timing of Soil-Residual Herbicide Applications for Control of Giant Ragweed (Ambrosia trifida)

Weed Technology ◽

10.1614/wt-d-15-00018.1 ◽

2015 ◽

Vol 29 (4) ◽

pp. 771-781 ◽

Cited By ~ 2

Author(s):

R. Joseph Wuerffel ◽

Julie M. Young ◽

Joseph L. Matthews ◽

Vince M. Davis ◽

William G. Johnson ◽

...

Keyword(s):

Field Experiments ◽

Early Spring ◽

Late Spring ◽

Weed Species ◽

Southern Illinois ◽

Application Timing ◽

Late Fall ◽

Emergence Patterns ◽

Giant Ragweed ◽

Residual Control

Fall-applied residual and spring preplant burn-down herbicide applications are typically used to control winter annual weeds and may also provide early-season residual control of summer annual weed species such as giant ragweed. Field experiments were conducted from 2006 to 2008 in southern Illinois to (1) assess the emergence pattern of giant ragweed, (2) evaluate the efficacy of several herbicides commonly used for soil-residual control of giant ragweed, and (3) investigate the optimal application timing of soil-residual herbicides for control of giant ragweed. Six herbicide treatments were applied at four application timings: early fall, late fall, early spring, and late spring. Giant ragweed first emerged in mid- and late-March in 2007 and 2008, respectively. The duration of emergence varied by year, with 95% of emergence complete in late May of 2008, but not until early July in 2007. Giant ragweed emergence occurred more quickly in plots that received a fall application of glyphosate + 2,4-D compared with the nontreated. Fall-applied residual herbicides did not reduce giant ragweed emergence in 2007 when compared with the nontreated, with the exception of chlorimuron + tribenuron applied in late fall. Giant ragweed control from early- and late-spring herbicide applications was variable by year. In 2007, saflufenacil (50 and 100 g ai ha−1) and simazine applied in early spring reduced giant ragweed densities by 95% or greater through mid-May; however, in 2008, early-spring applications failed to reduce giant ragweed emergence in mid-April. The only treatments that reduced giant ragweed densities by > 80% through early July were late-spring applications of chlorimuron + tribenuron or saflufenacil at 100 g ha−1. Thus, the emergence patterns of giant ragweed in southern Illinois dictates that best management with herbicides would include late-spring applications of soil-residual herbicides just before crop planting and most likely requires subsequent control with foliar or soil-residual herbicides after crop emergence.

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Factors Limiting the Recruitment of Eucalyptus salmonophloia in Remnant Woodlands .I. Pattern of Flowering, Seed Production and Seed Fall

Australian Journal of Botany ◽

10.1071/bt9940531 ◽

1994 ◽

Vol 42 (5) ◽

pp. 531 ◽

Cited By ~ 27

Author(s):

CJ Yates ◽

RJ Hobbs ◽

RW Bell

Keyword(s):

Seed Production ◽

Western Australia ◽

Seed Viability ◽

Fragmented Landscape ◽

Viable Seed ◽

Seed Fall ◽

Individual Trees ◽

Western Australian ◽

Remnant Population ◽

Conservation Of Biodiversity

Woodlands dominated by Eucalyptus salmonophloia F. Muell. occur throughout the fragmented landscape of the Western Australian wheatbelt. In most of these remnant woodlands, there is no regeneration of E. salmonophloia and this has become a concern for the conservation of biodiversity in the region. This study examined seed production, seed viability and pattern of seed fall in four remnant populations of E. salmonophloia in the central wheatbelt of Western Australia, to determine whether these factors are limiting recruitment. Surveys of flowering, seed production and seed fall were conducted over a two-year-period which included three potential flowering seasons. Individual trees flowered once over this period and the intensity of flowering and the proportion of flowers which set seed varied greatly between remnants. Seed from up to two consecutive flowering seasons was stored in the canopy, thus, E. salmonophloia formed substantial canopy seed stores. Seeds were released from this store throughout the year and seed fall showed only a weak winter decline. The viability of seeds released from the canopy store in each remnant population was high. These results indicate that the availability of viable seed is unlikely to be responsible for the lack of E. salmonophloia recruitment in remnant woodlands.

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Postharvest Kochia (Kochia scoparia) Management with Herbicides in Small Grains

Weed Technology ◽

10.1614/wt-03-164r1 ◽

2004 ◽

Vol 18 (2) ◽

pp. 426-431 ◽

Cited By ~ 11

Author(s):

James A. Mickelson ◽

Alvin J. Bussan ◽

Edward S. Davis ◽

Andrew G. Hulting ◽

William E. Dyer

Keyword(s):

Leaf Area ◽

Seed Production ◽

Field Experiments ◽

Optimal Timing ◽

Viable Seed ◽

Kochia Scoparia ◽

Application Timing ◽

Herbicide Treatments ◽

Small Grains ◽

Viable Seeds

Uncontrolled kochia plants that regrow after small-grain harvest can produce substantial numbers of seeds. An average of 4,100 seeds per plant were produced between harvest (late July to mid August) and the first killing frost (late September) at three locations in Montana. Field experiments were conducted to determine the optimal timing of postharvest herbicide applications to prevent kochia from producing viable seeds. Herbicide treatments were applied at three timings from late August to mid September. The most effective treatments were glyphosate (631 g/ha) and paraquat (701 g/ha) applied at the second application timing (late August to early September). These treatments reduced kochia seed production by 92% or greater at each site. Kochia regrowth by this time had sufficient leaf area for herbicide absorption, but few viable seed had been produced. Herbicide treatments at the first and third application timings were generally less effective and more variable in reducing kochia seed production. Sulfentrazone (157 g/ha) and 2,4-D (561 g/ha) were not as effective at reducing seed production as other herbicide treatments.

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Composting Reduces Seed Viability of Garlic Mustard (Alliaria petiolata) and Common Buckthorn (Rhamnus cathartica)

Invasive Plant Science and Management ◽

10.1614/ipsm-d-15-00005.1 ◽

2015 ◽

Vol 8 (3) ◽

pp. 284-291

Author(s):

Joseph Van Rossum ◽

Mark J. Renz

Keyword(s):

Invasive Plants ◽

Seed Viability ◽

Alliaria Petiolata ◽

State Agencies ◽

Management Process ◽

Garlic Mustard ◽

Rhamnus Cathartica ◽

Composting Facilities

AbstractComposting is a common practice for management of herbaceous yard materials and other decomposable materials. Although composting is promoted by state agencies for many materials, a notable exception is invasive plants due to concerns about spreading propagules with the finished product. To address this issue, we measured the viability of garlic mustard and common buckthorn seeds exposed to turned or static composting methods. Piles were built in 2012 and 2013, and seeds from both species were inserted and monitored for viability. Seed viability was reduced rapidly regardless of year, composting method, or species. Viability of seeds was zero within 7 and 15 d of composting for garlic mustard and common buckthorn, respectively, in both years. Results indicate that composting facilities are able to render the seeds of these invasive plants nonviable using either composting method because inactivation is within the composting timeframes typically practiced by the industry. This includes the process to further reduce pathogens (PFRP) with thresholds of 55 C for 15 d for the compost management process used for this trial.

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Invasive White Sweetclover (Melilotus officinalis) Control with Herbicides, Cutting, and Flaming

Invasive Plant Science and Management ◽

10.1614/ipsm-08-118.1 ◽

2009 ◽

Vol 2 (3) ◽

pp. 270-277 ◽

Cited By ~ 5

Author(s):

Jeffery S. Conn ◽

Steven S. Seefeldt

Keyword(s):

Seed Production ◽

Plant Density ◽

First Year ◽

Control Methods ◽

Viable Seed ◽

Melilotus Officinalis ◽

River Floodplains ◽

Glacial River ◽

Second Year ◽

And Control

AbstractWhite sweetclover is invading the Alaska glacial river floodplains and roadsides adjacent to natural areas, and control methods are needed. Chlorsulfuron, 2,4-DB, clopyralid, triclopyr, and 2,4-D controlled white sweetclover seedlings below recommended rates in the greenhouse. Biomass of established plants in the field was reduced by chlorsulfuron at recommended (17.6 g ai/ha), 1/2, and 1/4 rates and was reduced by triclopyr and 2,4-D at recommended rates (1,260 and 1,600 g ai/ha). Herbicides were more effective at reducing white sweetclover viable seed production in 2007 than in 2006. Only chlorsulfuron at 17.6 g ai/ha (recommended rate) eliminated seed production in both years. Flaming killed first-year plants, but some second-year plants resprouted and produced viable seed. Cutting at the 2.5 or 10 cm height did not control first-year plants because of regrowth, and second-year plant density and seed production was reduced by cutting at 2.5 cm but not by cutting at 10 cm.

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Effect of Herbicide Management Practices Used by Invasive Plant Managers onBerteroa incana(Hoary Alyssum) Seed Biology and Control

Invasive Plant Science and Management ◽

10.1017/inp.2018.15 ◽

2018 ◽

Vol 11 (2) ◽

pp. 101-106

Author(s):

Uriel D. Menalled ◽

Stacy C. Davis ◽

Jane M. Mangold

Keyword(s):

Population Density ◽

Seed Production ◽

Management Practices ◽

Invasive Plant ◽

Seed Viability ◽

Viable Seed ◽

Southwestern Montana ◽

Seed Biology ◽

Spraying Plants ◽

Herbicide Management

AbstractHoary alyssum [Berteroa incana(L.) DC.] is a nonnative invasive forb that is noxious in California, Idaho, Michigan, Montana, Oregon, Washington, Wyoming, Alberta, British Columbia, and Saskatchewan. ManagingB. incanais difficult, because it has an extended flowering period, during which plants simultaneously flower and produce seeds. Consequently, poorly timed herbicide applications may killB. incanaflowers but not prevent viable seed production. We examined how different herbicide management practices used by invasive plant managers affectedB. incanaseed production and viability the year of application as well as population density 1 yr after application. Professional invasive plant managers sprayedB. incanawith various herbicides as part of their current management practices at six sites in southwestern Montana in summer 2016. We collectedB. incanaplants at 4 wk postapplication for seed biology analyses. Across the six sites, nonsprayedB. incanaproduced 5 to 1,855 seeds plant−1and averaged 429 seeds plant−1. Seed production was reduced by 64% to 99% with 7 of the 11 herbicide applications.Berteroa incanaseed viability in nonsprayed areas averaged 53% and ranged from 36% to 73% across the sites. Nine of the 10 herbicide applications used by invasive plant managers reduced seed viability 49% to 100%. Few of the herbicide management practices reducedB. incana’s population density the following growing season, suggesting that managers should expect reoccurring infestations at least 1 yr after application. Our results show that invasive plant managers can reduceB. incanaviable seed production even when spraying plants that have flowered and formed seed pods. However, sites may need to be monitored for additional years to treat reoccurring infestations.

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