The U.S. Department of Agriculture–Agricultural Research Service (USDA-ARS) has been a leader in weed science research covering topics ranging from the development and use of integrated weed management (IWM) tactics to basic mechanistic studies, including biotic resistance of desirable plant communities and herbicide resistance. ARS weed scientists have worked in agricultural and natural ecosystems, including agronomic and horticultural crops, pastures, forests, wild lands, aquatic habitats, wetlands, and riparian areas. Through strong partnerships with academia, state agencies, private industry, and numerous federal programs, ARS weed scientists have made contributions to discoveries in the newest fields of robotics and genetics, as well as the traditional and fundamental subjects of weed–crop competition and physiology and integration of weed control tactics and practices. Weed science at ARS is often overshadowed by other research topics; thus, few are aware of the long history of ARS weed science and its important contributions. This review is the result of a symposium held at the Weed Science Society of America’s 62nd Annual Meeting in 2022 that included 10 separate presentations in a virtual Weed Science Webinar Series. The overarching themes of management tactics (IWM, biological control, and automation), basic mechanisms (competition, invasive plant genetics, and herbicide resistance), and ecosystem impacts (invasive plant spread, climate change, conservation, and restoration) represent core ARS weed science research that is dynamic and efficacious and has been a significant component of the agency’s national and international efforts. This review highlights current studies and future directions that exemplify the science and collaborative relationships both within and outside ARS. Given the constraints of weeds and invasive plants on all aspects of food, feed, and fiber systems, there is an acknowledged need to face new challenges, including agriculture and natural resources sustainability, economic resilience and reliability, and societal health and well-being.

Weeds and invasive plants know no borders and have collectively impacted many ecosystems worldwide, including croplands, forests, grasslands, rangelands, wetlands, and riparian areas. Losses continue to mount, affecting yield and productivity, species diversity, and ecosystem services, with both short- and long-term repercussions on the sustainability of plant and animal communities and the livelihoods of many. New and emerging invasive plants, along with many of the most intractable weeds, have undermined even the best control efforts, serving as a reminder of the constant need for improvements in science, application, and technology. One of the main reasons for the success of weeds and invasive plants is their ability to adapt to abiotic and biotic conditions, and research suggests that this will continue with minimal change.

ABSTRACT IMPACT: Use of this novel murine model of inflammatory bowel disease (IBD) and C. difficile infection (CDI) will aid in developing new clinical approaches to predict, diagnose, and treat CDI in the IBD population. OBJECTIVES/GOALS: IBD is associated with intestinal inflammation and alterations of the gut microbiota, both of which can diminish colonization resistance to C. difficile. Here, we sought to determine if IBD is sufficient to render mice susceptible to C. difficile colonization and infection in the absence of other perturbations, such as antibiotic treatment. METHODS/STUDY POPULATION: C57BL/6 IL-10-/- mice were colonized with Helicobacter hepaticus to trigger colonic inflammation akin to human IBD. Control mice, not colonized with H. hepaticus, were pretreated with the antibiotic cefoperazone to render the gut microbiota susceptible to CDI. Mice were then gavaged with spores of the toxigenic C. difficile strain VPI 10463 and monitored for C. difficile colonization and disease. The fecal microbiota at the time of C. difficile exposure was profiled by 16S rRNA gene sequencing and analyzed using mothur. Statistical analyses were performed using R. RESULTS/ANTICIPATED RESULTS: Mice with IBD harbored significantly distinct intestinal microbial communities compared to non-IBD controls at the time of C. difficile spore exposure (14 days post-IBD trigger). Mice with IBD were susceptible to persistent C. difficile colonization, while genetically identical non-IBD controls were resistant to C. difficile colonization. Concomitant IBD and CDI was associated with significantly worse clinical and intestinal disease than unaccompanied IBD. DISCUSSION/SIGNIFICANCE OF FINDINGS: Patients with IBD who develop concurrent CDI experience increased morbidity and mortality. These studies in a novel mouse model of IBD and CDI emphasize the dual importance of host responses and alterations of the gut microbiota in susceptibility to C. difficile colonization and infection in the setting of IBD.

Benzobicyclon will be the first 4-hydroxyphenylpyruvate dioxygenase (HPPD)–inhibiting herbicide available in US rice production pending registration completion. An observation of benzobicyclon controlling weedy rice in two field trials prompted a greenhouse and field evaluation to determine if benzobicyclon would control weedy rice accessions from Arkansas, Mississippi, and southeastern Missouri. A total of 100 accessions were screened in the greenhouse and field. Percentage mortality was determined in the greenhouse, and percentage control was recorded in the field. Benzobicyclon at 371 g ai ha–1 caused at least 80% mortality of 22 accessions in the greenhouse and at least 80% control of 30 accessions in the field. For most accessions, individual plants within the accession varied in response to benzobicyclon. Based on these results, the sensitivity of weedy rice to benzobicyclon varies across accessions collected in the midsouthern United States, and it may provide an additional control option for weedy rice in some fields.

Three annual plant species — erect plantain (Plantago erecta Morris), common chickweed [Stellaria media (L.) Cyrill.], and silver hairgrass (Aira caryophyllea L.)—are commonly found and may dominate a unique flora on areas sprayed with paraquat (1,1′-dimethyl-4,4′-bipyridinium ion) in cismontane rangelands of California. The basis of this phenomenon is shown to be temperature-related germination requirements, novel seed characteristics, and lack of competition.

The phenology of reproduction was highly variable among 23 selections of medusahead (Taeniatherum asperum (Sim.) Nevski). Selections with markedly early and late maturity were observed. The phenology generally was consistent during 4 years of testing at Reno, Nevada, and during 2 years at Davis, California. Individual selections differed greatly in phenology between two locations. Some of the selections exhibited phenotypic plasticity in phenology when grown in competition with other weeds.

Eighteen soil-active herbicides were evaluated for control of downy brome (Bromus tectorum L.) and associated broadleaf weeds during revegetation of big sagebrush (Artemisia tridentata Nutt.) rangelands in Nevada and in northeastern California. We rated all herbicides in reference to a chemical-fallow program for replacement of vegetation, where seeding follows and is separated from herbicide application by at least 1 year. Atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) applied at 1 lb/A was the most promising treatment with respect to three essential characteristics: length of activity, spectrum of weed control, and relative preemergence and postemergence phytotoxicity.

The financial system is governed not just by formal rules but also by social relationships that pervade the elite strata of society. Understanding such dynamics entails understanding complex relational ties between actors, a task that can be facilitated through the use of network analysis. We argue that a latent feature of interest to scholars of the political economy of finance is one of social distance, which is a measurable concept. Using new data from the financial sector, we measure the social distance between a range of financial firms and one key regulator, the U.S. Securities and Exchange Commission (SEC), over time to assess whether or not social distance is related to organizations’ advocacy behavior. We find a positive relationship between how close a given organization is to the SEC and how often it engages in advocacy. The result persists when we control for numerous factors related to organizational characteristics, firm size, and when we measure advocacy frequency in different ways.

Field studies were conducted at 35 sites throughout the north-central United States in 1998 and 1999 to determine the effect of postemergence glyphosate application timing on weed control and grain yield in glyphosate-resistant corn. Glyphosate was applied at various timings based on the height of the most dominant weed species. Weed control and corn grain yields were considerably more variable when glyphosate was applied only once. The most effective and consistent season-long annual grass and broadleaf weed control occurred when a single glyphosate application was delayed until weeds were 15 cm or taller. Two glyphosate applications provided more consistent weed control when weeds were 10 cm tall or less and higher corn grain yields when weeds were 5 cm tall or less, compared with a single application. Weed control averaged at least 94 and 97% across all sites in 1998 and 1999, respectively, with two glyphosate applications but was occasionally less than 70% because of late emergence of annual grass and Amaranthus spp. or reduced control of Ipomoea spp. With a single application of glyphosate, corn grain yield was most often reduced when the application was delayed until weeds were 23 cm or taller. Averaged across all sites in 1998 and 1999, corn grain yields from a single glyphosate application at the 5-, 10-, 15-, 23-, and 30-cm timings were 93, 94, 93, 91, and 79% of the weed-free control, respectively. There was a significant effect of herbicide treatment on corn grain yield in 23 of the 35 sites when weed reinfestation was prevented with a second glyphosate application. When weed reinfestation was prevented, corn grain yield at the 5-, 10-, and 15-cm application timings was 101, 97, and 93% of the weed-free control, respectively, averaged across all sites. Results of this study suggested that the optimum timing for initial glyphosate application to avoid corn grain yield loss was when weeds were less than 10 cm in height, no more than 23 d after corn planting, and when corn growth was not more advanced than the V4 stage.

Field experiments were conducted across the north-central United States to determine the benefits of various weed control strategies in corn. Weed control, corn yield, and economic return increased when a preemergence (PRE) broad-spectrum herbicide was followed by (fb) postemergence (POST) herbicides. Weed control decisions based on field scouting after a PRE broad-spectrum herbicide application increased weed control and economic return. Application of a PRE grass herbicide fb a POST herbicide based on field scouting resulted in less control of velvetleaf and morningglory species, corn yield, and economic return compared with a PRE broad-spectrum herbicide application fb scouting. Cultivation after a PRE broad-spectrum herbicide application increased weed control and corn yield compared with the herbicide applied alone, but economic return was not increased. An early-postemergence herbicide application fb cultivation resulted in the highest level of broadleaf weed control, the highest corn yield, and the greatest economic return compared with all other strategies. Weed control based on scouting proved to be useful in reducing the effect of weed escapes on corn yield and increased economic return compared with PRE herbicide application alone. However, economic return was not greater than the PRE fb planned POST or total POST strategies.