Investigations of the relevance of low tunnel methodology and air sampling concerning the off-target movement of dicamba were conducted from 2018 to 2022, focused primarily on volatility. This research, divided into three experiments, evaluated the impact of herbicides and adjuvants added to dicamba and the type of surface treated on dicamba volatility. Treatment combinations included glyphosate and glufosinate, the presence of a simulated contamination rate of ammonium sulfate (AMS), the benefit of a volatility reduction agent (VRA), and a vegetated (dicamba-resistant cotton) or soil surface treated with dicamba. Volatility assessments included air sampling collected over 48 h. Dicamba treatments were applied four times to each of two bare soil or cotton trays and placed inside the tunnels. The extraction and quantification of dicamba from air samples were conducted. Field assessments included the maximum and average visible injury in bioindicator soybean and the lateral movement of dicamba damage expressed by the furthest distance from the center of the plots to the position in which plants had 5% injury. Adding glufosinate and glyphosate to dicamba increased the dicamba amount in air samples. A simulated tank contamination rate of AMS (0.005% v/v) did not impact dicamba emissions compared to a treatment lacking AMS. Adding a VRA reduced dicamba in air samples by 70% compared to treatment without the adjuvant. Dicamba treatments applied on vegetation generally produced greater amounts of dicamba detected than treatments applied to bare soil. Field assessment results usually followed differences in dicamba concentration by treatments tested. Results showed that low tunnel methodology allowed simultaneous comparisons of several treatment combinations concerning dicamba volatility.

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.

Damage to non–dicamba resistant (non-DR) soybean [Glycine max (L.) Merr.] has been frequent in geographies where dicamba-resistant (DR) soybean and cotton (Gossypium hirsutum L.) have been grown and sprayed with the herbicide in recent years. Off-target movement field trials were conducted in northwest Arkansas to determine the relationship between dicamba concentration in the air and the extent of symptomology on non-DR soybean. Additionally, the frequency and concentration of dicamba in air samples at two locations in eastern Arkansas and environmental conditions that impacted the detection of the herbicide in air samples were evaluated. Treatment applications included dicamba at 560 g ae ha−1 (1X rate), glyphosate at 860 g ae ha−1, and particle drift retardant at 1% v/v applied to 0.37-ha fields with varying degrees of vegetation. The relationship between dicamba concentration in air samples and non-DR soybean response to the herbicide was more predictive with visible injury (generalized R 2 = 0.82) than height reduction (generalized R 2 = 0.43). The predicted dicamba air concentration resulting in 10% injury to soybean was 1.60 ng m−3 d−1 for a single exposure. The predicted concentration from a single exposure to dicamba resulting in a 10% height reduction was 3.78 ng m−3 d−1. Dicamba was frequently detected in eastern Arkansas, and daily detections above 1.60 ng m−3 occurred 17 times in the period sampled. The maximum concentration of dicamba recorded was 7.96 ng m−3 d−1, while dicamba concentrations at Marianna and Keiser, AR, were ≥1 ng m−3 d−1 in six samples collected in 2020 and 22 samples in 2021. Dicamba was detected consistently in air samples collected, indicating high usage in the region and the potential for soybean damage over an extended period. More research is needed to quantify the plant absorption rate of volatile dicamba and to evaluate the impact of multiple exposures of gaseous dicamba on non-targeted plant species.

Gravitational waves from coalescing neutron stars encode information about nuclear matter at extreme densities, inaccessible by laboratory experiments. The late inspiral is influenced by the presence of tides, which depend on the neutron star equation of state. Neutron star mergers are expected to often produce rapidly rotating remnant neutron stars that emit gravitational waves. These will provide clues to the extremely hot post-merger environment. This signature of nuclear matter in gravitational waves contains most information in the 2–4 kHz frequency band, which is outside of the most sensitive band of current detectors. We present the design concept and science case for a Neutron Star Extreme Matter Observatory (NEMO): a gravitational-wave interferometer optimised to study nuclear physics with merging neutron stars. The concept uses high-circulating laser power, quantum squeezing, and a detector topology specifically designed to achieve the high-frequency sensitivity necessary to probe nuclear matter using gravitational waves. Above 1 kHz, the proposed strain sensitivity is comparable to full third-generation detectors at a fraction of the cost. Such sensitivity changes expected event rates for detection of post-merger remnants from approximately one per few decades with two A+ detectors to a few per year and potentially allow for the first gravitational-wave observations of supernovae, isolated neutron stars, and other exotica.

Objectives: Executive dysfunction is a common feature in Parkinson’s disease (PD). However, there is a lack of brief validated instruments for executive dysfunction in PD. Methods: The aim of the present study was to assess the relation of Frontal Assessment Battery (FAB) scores to age and education, to verify the utility of FAB in the evaluation of executive dysfunction in PD and to differentiate between controls (n=41), PD patients with normal cognition (PD-NC; n=41; Hoehn and Yahr stages 2–3) and PD with mild cognitive impairment (PD-MCI; n=32; Hoehn and Yahr stages 2–3). In addition, we studied the relation between voxel-based morphometric (VBM) data and FAB results in PD. Results: We found that FAB scores are significantly related to age and education. The FAB has shown discriminative validity for the differentiation of PD-MCI from PD-NC and controls (area under the curve >.80). Also, the VBM analysis revealed lower FAB scores are specifically related to lower gray matter density in the right ventromedial prefrontal areas and precuneus. Conclusions: The FAB can be recommended as a valid instrument for PD-MCI Level I screening. FAB is sensitive to frontal lobe involvement in PD as reflected by lower gray matter density in prefrontal areas. (JINS, 2017, 23, 675–684)

Growth chamber experiments evaluated the influence of ambient temperature and soil moisture on cotton and velvetleaf response to pyrithiobac. Additional studies determined the basis for observed plant responses to 14C pyrithiobac. Cotton injury from six times the normal dosage was < 20% at 2 wk for all temperatures and soil moistures. Pyrithiobac injured velvetleaf less at lower soil moistures. Both species absorbed more 14C-pyrithiobac at 30/28 or 35/33 C than at 25/23 C. Cotton absorbed more herbicide than velvetleaf at all temperatures and soil moistures. Velvetleaf translocated < 16% of absorbed 14C out of the treated leaf while cotton translocated < 3% of absorbed material. At warmer temperatures, velvetleaf translocated less 14C when soil was dry (–1.0 MPa) than when plants were watered to field capacity (–0.03 MPa). This decreased absorption and translocation may affect pyrithiobac activity on velvetleaf growing in dry soil. Translocation differences did not fully explain whole plant effects. The metabolism difference may account for cotton tolerance.

Fluometuron adsorption and dissipation under field and laboratory conditions, and distribution within the soil profile was determined in 3 soils from Tennessee, Mississippi, and Georgia that are representative of the cotton-growing regions of the southeastern United States. Fluometuron adsorption was correlated with organic matter, but not with clay content or soil pH. First-order kinetics explained fluometuron dissipation under field and controlled conditions (r2 ≥ 0.82). Field dissipation of fluometuron was slower under dry conditions. Fluometuron was not detected below 15 cm in the soil profile in any soil, and concentrations in the 8- to 15-cm soil zone were < 15 ppbw 112 d after treatment. Fluometuron dissipation was more rapid in soil from the 0- to 8-cm depth in Tennessee soil than in Mississippi soil under controlled conditions. Dissipation was more rapid under field conditions than under laboratory conditions at 2 of 3 locations. Fluometuron half-lives in soils from the 0- to 8-cm depth ranged from 9 to 28 d under field conditions and from 11 to 43 d in the laboratory. Fluometuron dissipation in soils from 30- to 45- and 60- to 90-cm depths was not different among soils, with half-lives ranging from 58 to 99 d under laboratory conditions. Fluometuron half-life was positively correlated with soil depth and inversely correlated with organic matter. These data indicate that organic matter, soil depth, and environmental conditions affect fluometuron dissipation.

Field research was conducted in Tennessee at Jackson in 1991 and at Milan in 1992 to compare the effect of MSMA and pyrithiobac on cotton development, yield, and quality. In separate treatments to different plots, pyrithiobac at 0.14 kg ai ha–1 did not affect development, yield, and quality of cotton. MSMA at 2.24 kg ai ha–1 decreased cotton plant internode length 10 to 15% and height by 15% 5 wk after late treatment both years. MSMA applied to 50 cm cotton reduced subsequent plant height in 1992, but other plant characteristics were not affected. In 1991, MSMA increased squares and decreased blooms and bolls for monopodia and sympodia position one and two, which suggested a delay in plant development. In 1991, mechanical harvest lint yields were decreased by MSMA at first harvest while increasing second harvest lint yields. However, in 1991 only MSMA applied late decreased total harvest lint yield 20%. Plant mapping data determined that the yield decrease was a result of decreased yields at sympodia positions one and two. Cotton seed arsenic analysis indicated that MSMA-late increased arsenic levels by ≈ 1 ppmw in 1991 for sympodia at position one and two compared to the untreated check, while position two contained the highest level of 1.8 ppmw.

Field studies indicated thiazopyr at 220 g ha−1 injured soybeans planted in no-till, and 340 g ha−1 injured soybean in 1 of 2 yr planted into tilled soil. Thiazopyr half-lives in three field studies ranged from 12 to 14 d, indicating minimal potential for carryover injury to sensitive rotational crops. Thiazopyr dissipation under controlled conditions was slower than under field conditions. Half-lives at 15 and 30 C were 133 and 43 d, respectively. This indicates that microbial degradation is an important mechanism in thiazopyr dissipation, but that other loss mechanisms also play a role. A method using methanol extraction of moist soil samples followed by gas chromatography using a nitrogen-phosphorous detector had > 90% recovery of thiazopyr.

Fluometuron adsorption and degradation were determined in soil collected at three depths from no-till + no cover, conventional-till + no cover, no-till + vetch cover, and conventional-till + vetch cover in continuous cotton. These combinations of tillage + cover crop + soil depth imparted a range of organic matter and pH to the soil. Soil organic matter and pH ranged from 0.9 to 2.5% and from 4.7 to 6.5, respectively. Fluometuron adsorption was affected by soil depth, tillage, and cover crop. In surface soils (0 to 4 cm), fluometuron adsorption was greater in no-till + vetch plots than in conventional-tilled + no cover plots. Soil adsorption of fluometuron was positively correlated with organic matter content and cation exchange capacity. Fluometuron degradation was not affected by adsorption, and degradation empirically fit a first-order model. Soil organic matter content had no apparent effect on fluometuron degradation rate. Fluometuron degradation was more rapid at soil pH > 6 than at pH ≤ 5, indicating a potential shift in microbial activity or population due to lower soil pH. Fluometuron half-life ranged from 49 to 90 d. These data indicate that tillage and cover crop may affect soil dissipation of fluometuron by altering soil physical and chemical properties that affect fluometuron degrading microorganisms or bioavailability.

Norflurazon adsorption and dissipation under field and laboratory conditions, and distribution within the soil profile were determined in three soils representative of cotton-growing regions of the southeastern U.S. Norflurazon adsorption was greater in soil from 0 to 8 cm in a Lexington silt loam (Tennessee) and a Beulah silt loam (Mississippi) than in a Dothan loamy sand (Georgia). Adsorption was directly related to organic matter. Norflurazon degradation under controlled conditions in soil from 0 to 8 cm from each state was not different among locations, with half-lives ranging from 63 to 167 d. Degradation at 30 C in soil from the 30- to 45- and 60- to 90-cm depths was not different among locations, and was slower at the 60- to 90-cm depth than in surface soil. Norflurazon dissipation was more rapid under field conditions than under laboratory conditions, with half-lives ranging from 7 to 79 d in the 0- to 8-cm soil horizon. Dry field conditions slowed norflurazon dissipation. Norflurazon was not detected below 15 cm in the profile in any soil, and concentrations in the 8- to 15-cm soil zone were < 36 ppbw 112 d after treatment.

The ability of the pesticide root zone model (PRZM) and the groundwater-loading effects of agricultural management systems (GLEAMS) model to predict movement of two herbicides in soil was evaluated using site-specific environmental data from sites in three states. Predictions of herbicide movement with site-specific data were compared to predictions using more generalized database soil and pesticide data within each model. Field experiments examined fluometuron and norflurazon movement in three soils representative of the cotton-growing regions of the southeastern United States. In comparing the use of site-specific vs. database values, the small increase in accuracy using site-specific inputs would not justify the large cost to obtain the data. The databases for each model gave predictions similar to those using the site-specific numbers. Both the PRZM and the GLEAMS model had similar accuracy levels in predicting the presence of fluometuron or norflurazon present in three surface soils, although each model tended to overpredict movement and total herbicide concentration, especially at lower herbicide concentrations. At higher herbicide concentrations, prediction accuracy was less than that probably needed to predict agronomically relevant herbicide concentrations in surface soils.

Broadleaf signalgrass is sensitive to nicosulfuron and resistant to primisulfuron, but corn is resistant to both. Research was conducted to determine the effect of varying light level and air temperature on absorption, translocation, and metabolism of nicosulfuron and primisulfuron in broadleaf signalgrass and corn. Corn absorbed between 60 and 85% of the applied nicosulfuron and primisulfuron within 72 h after treatment (HAT), depending on environmental treatment. Absorption, translocation, and metabolism all tended to be more rapid at higher temperature and light intensity. Nicosulfuron and primisulfuron translocation out of the treated leaf was < 4.5% of herbicide absorbed through 72 HAT. Corn rapidly metabolized both herbicides in both environments. However, primisulfuron was metabolized more rapidly (high = 99%, low = 92%) than nicosulfuron (high = 95%, low = 78%). Broadleaf signalgrass absorbed 20% more nicosulfuron than primisulfuron through 72 HAT. Nicosulfuron translocation out of the treated leaf in broadleaf signalgrass was ≤ 15% absorbed through 72 HAT, while primisulfuron translocation was ≤ 4% during the same time period. Primisulfuron metabolism was more rapid than nicosulfuron in broadleaf signalgrass. During the first 4 HAT, broadleaf signalgrass metabolized > 20 times more primisulfuron than nicosulfuron. By 72 HAT, broadleaf signalgrass under conditions of high light and temperature had metabolized nearly 90% of the primisulfuron absorbed but ≤ 7% of the nicosulfuron absorbed was metabolized during the same time. These results suggest that differential activity of nicosulfuron and primisulfuron on broadleaf signalgrass may be based on differential rates of metabolism to nonphytotoxic compounds; uptake and translocation differences agree with the differential broadleaf signalgrass activity. Additionally, environment has the potential to affect rates of sulfonylurea absorption, translocation, and metabolism.