Modeling weed community diversity based on species population density dynamics and herbicide use intensity

Oreja, Fernando H.; Inman, Matthew D.; Jordan, David L.; Bardhan, Deepayan; León, Ramón G.

doi:10.1016/j.eja.2022.126533

Cited by 4 publications

(2 citation statements)

References 49 publications

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“…In the absence of additional management tactics, we can expect continual additions of weed seed to the seedbank. In other studies, the addition of herbicide to the production system further reduces the population growth rate compared with the levels seen in our study and alters weed community composition trajectories from season to season (Oreja et al 2021, 2022a, 2022b).…”

Section: Resultscontrasting

confidence: 39%

Demographics of Palmer amaranth (Amaranthus palmeri) in annual and perennial cover crops

Weisberger,

Leon,

Gruner

et al. 2023

Weed Sci

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Palmer amaranth (Amaranthus palmeri S. Watson) is the most problematic weed of cotton cropping systems in the Southeast US. Heavy reliance on herbicides has selected for resistance to multiple herbicide mechanisms of action. Effective management of this weed may require the integration of cultural practices that limit germination, establishment, and growth. Cover crops have been promoted as a cultural practice that targets these processes. We conducted a two-year study in Georgia, USA, to measure the effects of two annual cover crops (cereal rye [Secale cereale L.] and crimson clover (Trifolium incarnatum L.), a perennial living mulch (Durana® white clover, (Trifolium repens L.), and a bare ground control on A. palmeri population dynamics. The study was conducted in the absence of herbicides. Growth stages were integrated into a basic demographic model to evaluate differences in population trajectories. Cereal rye treatments suppressed weed seedling recruitment (seedlings seed-1) by 19.2 and 13 times, and living mulch 12 and 25 times more than the bare ground control. Low recruitment was correlated positively with low light transmission (above canopy PAR/below cover crop PAR) at the soil surface. Low recruitment rates were also negatively correlated with high survival rates. Greater survival rates and reduced adult plant densities resulted in greater biomass (g plant-1) and fecundity (seeds plant-1) in cereal rye and living mulch treatments in both years. The annual rate of population change (seeds seed-1) was equivalent across all treatments in the first year but was greater in the living mulch treatment in the second year. Our results highlight the potential of annual cover crops and living mulches for suppressing A. palmeri seedling recruitment and would be valuable tools as part of an integrated weed management strategy.

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Section: Resultscontrasting

confidence: 39%

Demographics of Palmer amaranth (Amaranthus palmeri) in annual and perennial cover crops

Weisberger,

Leon,

Gruner

et al. 2023

Weed Sci

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“…Introducing new management tools that include both chemical and nonchemical controls can produce weed species shifts (Cordeau et al 2017;Culpepper 2006;de la Fuente et al 2021Tuesca et al 2001. The repeated use of a few herbicides over time in weed management can reduce weed diversity (Oreja et al 2022), resulting in a few dominant species that are difficult to manage, frequently exhibit herbicide resistance, and ultimately can cause important yield losses (Storkey and Neve 2018). Herbicide programs play a key role in weed shifts and the pace at which these occur (Menalled et al 2001).…”

Section: Introductionmentioning

confidence: 99%

Effect of cotton herbicide programs on weed population trajectories and frequency of glyphosate-resistant Palmer amaranth (Amaranthus palmeri)

et al. 2022

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The adoption of dicamba-resistant cotton (Gossypium hirsutum L.) cultivars allows using dicamba to reduce weed populations across growing seasons. However, the overuse of this tool risks selecting new herbicide resistant biotypes. The objectives of this research were to determine the population trajectories of several weed species and track the frequency of glyphosate-resistant Palmer amaranth (Amaranthus palmeri S. Watson) (GR) over 8 years in dicamba-resistant cotton. An experiment was established in North Carolina in 2011, and during the first four years, different herbicide programs were applied. These programs included postemergence applications of glyphosate, alone or with dicamba, with or without residual herbicides. During the last 4 years, all programs received glyphosate plus dicamba. Biennial rotations of postemergence applications of glyphosate only and glyphosate plus dicamba postemergence with and without preemergence herbicides were also included. Sequential applications of glyphosate plus dicamba were applied to the entire test area for the final 4 years of the study. No herbicide program was entirely successful in controlling the weed community. Weed population trajectories were different according to species and herbicide program, creating all possible outcomes; some increased, other decreased, and others remained stable. Density of resistant A. palmeri increased during the first 4 years with glyphosate only programs (up to 11739 plants per m2) and decreased a 96% during the final 4 years when glyphosate plus dicamba was implemented. This species had a strong influence on population levels of other weed species in the community. Goosegras [Eleusine indica (L.) Gaertn.] was not affected by A. palmeri population levels and even increased its density in some herbicide programs, indicating that not only herbicide resistance but also reproductive rates and competitive dynamics are critical for determining weed population trajectories under intensive herbicide-based control programs. Frequency of GR reached a maximum of 62% after 4 years and maintained those levels until the end of the experiment.

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Molecular analysis of St. Augustinegrass cultivar mixtures composition over time and latitude

van der Laat,

Leon,

Dale

et al. 2024

Crop Science

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St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] is commonly planted in residential and commercial landscapes as a cultivar monoculture predisposing this lawn to pest invasion and high‐maintenance inputs. Researchers have suggested that increasing genetic diversity by growing cultivars in mixtures may increase turfgrass stress resilience. However, the stability and uniformity of those mixtures has not been studied. The present study was carried out to evaluate the stability of St. Augustinegrass cultivars mixtures over time and across three latitudes. The study was conducted in Citra and Fort Lauderdale, FL, and Jackson Springs, NC. Simple‐sequence repeats markers were used to genotype leaf samples of St. Augustinegrass cultivars planted in two‐ and four‐cultivar mixtures. Leaf samples were collected 1 and 3 years after establishment. In all locations, cultivar richness and evenness declined over time. Similarly, the relative abundance of the least persistent cultivars decreased approximately 50%–100% depending on cultivar and location. Differences in growth patterns among cultivars resulted in cultivar displacement and the predominance of a single cultivar. Cultivars that covered the ground faster or formed dense canopies early after establishment were dominant at the end of the study. Locally developed cultivars tended to be more dominant in their original latitude. The use of cultivar mixtures may help the identification of vigorous, competitive, and stress tolerant cultivars in turfgrass breeding programs. However, their commercial use remains challenging as if the patterns observed here for 3 years are representative of a continuous trend, and they do not persist over time.

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Modeling weed community diversity based on species population density dynamics and herbicide use intensity

Cited by 4 publications

References 49 publications

Demographics of Palmer amaranth (Amaranthus palmeri) in annual and perennial cover crops

Demographics of Palmer amaranth (Amaranthus palmeri) in annual and perennial cover crops

Effect of cotton herbicide programs on weed population trajectories and frequency of glyphosate-resistant Palmer amaranth (Amaranthus palmeri)

Molecular analysis of St. Augustinegrass cultivar mixtures composition over time and latitude

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