Herbicide Solution Research Articles

Industrial hemp biomass negatively affected by herbicide drift from corn and soybean herbicides.

The establishment of industrial hemp (Cannabis sativa L.) fields near row crops has raised concerns about the potential adverse effects of herbicide drift on hemp production. This study examined hemp susceptibility to drift of herbicides registered for use in corn and/or soybeans. Herbicide solutions (2,4-D, dicamba, glufosinate, glyphosate, imazethapyr, lactofen, mesotrione) were applied separately in the wind tunnel (3.6m s-1 airspeed), simulating drift scenarios, with conventional TP95015EVS (TP) and air inclusion AI95015EVS (AI) flat fan nozzles calibrated to deliver 140L ha-1 carrier volume at 230kPa. Mylar cards and hemp plants (20-25cm tall) were placed downwind up to 12m. Spray deposition from mylar cards was quantified using fluorometry and hemp biomass was collected 21 post application. Results indicated the nozzle design influenced downwind deposition; 5% of spray deposits from the TP nozzle reached 5.9 m downwind versus 2.0 m for the AI nozzle. Glyphosate, glufosinate, and mesotrione caused the highest biomass reductions, with 50% reductions observed at 19.3 (inferred), 8.7, and 9.3m downwind for TP nozzle, and 4.1, 4.0, and 2.9m for AI nozzle. These findings suggest herbicide applications at airspeeds of 3.6m s-1 or greater present a risk to nearby hemp fields.

A means of destroying sites of perennial root shoot weeds with pests and diseases in them

BACKGROUND: The subject of the study is the technological process of protective spraying of agricultural crops using a combined method against perennial weeds in sites in the field using two pneumohydraulic devices with slot atomizers as part of an improved small-sized boom sprayer. AIM: Development of a technical mean for exterminating sites of perennial root shoot weeds with pests and diseases in them. METHODS: The developed pneumohydraulic devices were used for an improved mounted boom sprayer of plants to treat sites of perennial weeds in the field. Chemical spraying with combined use of the traditional method and the developed pneumohydraulic devices with axial fans and 12 V electric motors, ensuring the distribution of droplet liquid on the treatment surface with two sprayers over 4 meters, is able to reduce the amount of the applied chemicals compared to the conventional technology and to reduce the pesticide load on crop plants by local destruction of sites of weeds, pests and diseases. Based on the developed methods, the results of spraying the surface with a drop liquid with a known dispersion using slot sprayers and controlled liquid pressures with a dial gauge during experiments were obtained. SCIENTIFIC NOVELTY: For the first time, a combined method and technical mean of achieving the research aim have been proposed for the destruction of sites of perennial weeds in the field and the diseases and pests of agricultural crops spread in them. RESULTS: When using a mounted sprayer with two containers for working fluids of combined herbicide solutions or for an insecticide solution in one of the containers and installation of the improved pneumohydraulic devices on the edges of the boom with a conventional arrangement of slot atomizers, it is possible to meet agrotechnical requirements for the use of herbicides, insecticides and fungicides. The simultaneous impact of large drops of herbicides on weeds and the penetration of small drops into plants will destroy sites of rhizome and root weeds with pests and diseases to ensure favorable conditions for the production of agricultural crops. CONCLUSION: A combined method and the technical mean of chemical treatment of perennial weeds with pests and diseases to create favorable conditions for the production of cultivated plants has been experimentally substantiated. Compliance with the conditions is ensured by equipping the mounted sprayer with two containers, pumps for supplying liquid through hoses to slot atomizers, and installing pneumohydraulic liquid nozzles at the edges of the boom. Working liquid sprayers ensure spraying width of more than 4 m, taking into account the size of a site, as well as spraying inaccessible areas using conventional technical means. The efficiency of the developed combined protective spraying of agricultural crops against perennial weeds and pests by the technical mean of its implementation lies in the savings of expensive herbicides and insecticides up to 70% in the later stages of their growing season (as they grow over the field area) compared to the forced continuous application of the herbicide over the entire field area.

A Facile Determination of Herbicide Residues and Its Application in On-Site Analysis.

Abuse of herbicides in food safety is a vital concern that has an influence on the sustainable development of the world. This work presents, a modified ionization method with separation of the sample and carrier gas inlets, which was utilized for efficient ionization and analyte transfer of herbicides in crops. The working parameters of voltage, injective distance, desorption temperature, and the carrier gas flow rate were optimized to achieve the high efficiency of the transfer and ionization of the analyte. When it was applied in the analysis of herbicides in laboratory, the method exhibited excellent performance in achieving the quantitative detection of herbicides in solutions and residues spiked in an actual matrix with a limit of quantification of 1-20 μg/kg and relative standard deviations of less than 15%. Although a simple QuEchERS process was used, the programmable heating platform ensured efficient gasification and transfer of the target analyte, with the advantages of high speed and selectivity, avoiding the noted matrix effect. The method exhibited a relatively acceptable performance by using air as the discharged gas (open air). It could be used to monitor herbicide residues in the growth stage via on-site non-destructive analysis, which obtained low LODs by dissociating the herbicides from the crops without any pretreatment. It showed great potential for the supervision of the food safety market by achieving non-destructive detection of crops anytime and anywhere. This finding may provide new insights into the determination of pesticide emergence and rice quality assessment.

Efeitos do glifosato na morfologia e no ciclo celular de plântulas de soja tolerantes e sensíveis ao herbicida

Abstract The objective of this work was to evaluate the phytotoxic and cytogenotoxic effects of gly phosate on the direct development of soybean seedlings tolerant and sensitive to this herbicide. Seeds of one cultivar sensitive to and of two tolerant to glyphosate were placed to germinate in contact with distilled water (control) and two herbicide solutions (distilled water + 0.06 or 0.12% glyphosate), at 25°C, for seven days. Seedling responses to glyphosate were evaluated through the germination test, the seedling growth test, and the cell-cycle analysis (mitotic index and rate of abnormalities), carried out on the third, fourth, fifth, and seventh days after sowing. In the germination test under the herbicide treatments, no normal seedlings were observed for the sensitive cultivar, only for the tolerant ones. The herbicide treatments reduced the length of the seedlings and altered their morphology, making the radicle smaller than the hypocotyl. Regarding cytogenotoxic effects, glyphosate had a mitodepressive action on sensitive and tolerant seedlings, while the rate of abnormalities increased only in the sensitive cultivar. Glyphosate negatively affects the development of soybean seedlings at a macroscopic and cellular level, especially in cultivars sensitive to this herbicide.

Trimethylation Enhancement Using Diazomethane (TrEnDi) Enables Enhanced Detection of Glufosinate and 3-(Methylphosphinico)propionic Acid from Complex Canola Samples.

Over the past century, agriculture practices have transitioned from manual cultivation to the use of an array of chemical herbicides for weed control including phosphinothricin, or glufosinate (GLUF). Consequently, the potential for long-term residual GLUF exposure in the food chain has increased, highlighting the need for improved analytical strategies for its detection, as well as the detection of its main breakdown product 3-(methylphosphinico)propionic acid (MPPA). Chemical derivatization strategies have been developed to improve the detection of GLUF and MPPA via liquid chromatography tandem mass spectrometry analyses. Herein, we employ trimethylation enhancement using diazomethane (TrEnDi) for the first time as a means to confer analytical advantages via quantitatively derivatizing these analytes into permethylated GLUF ([GLUFTr]+) and MPPA ([MPPATr+H]+). Comparing [GLUFTr]+ and [MPPATr+H]+ to underivatized counterparts, TrEnDi yields 2.8-fold and 1.7-fold improvements in reversed-phase chromatographic retention, respectively, while MS-based sensitivity is enhanced 4.1-fold and 11.0-fold, respectively. Successful analyte derivatization (with >99% yields) was further demonstrated on a commercial herbicide solution imparting consistent analytical enhancements. To investigate the benefits of TrEnDi in a bona fide agricultural scenario, simple aqueous extractions from distinct parts of field-grown canola plants were performed to quantify GLUF and MPPA before and after TrEnDi derivatization. In their underivatized forms, GLUF and MPPA were undetectable in all field samples, whereas [GLUFTr]+ and [MPPATr+H]+ were readily quantifiable using the same analysis conditions. Our results demonstrate that TrEnDi continues to be a useful tool to enhance the analytical characteristics of organic molecules that are traditionally difficult to detect.

Impact of chemical weed management in sugar beet ( Beta vulgaris) on productivity, quality and economics

Weeds in sugar beet ( Beta vulgaris L.) can contribute to a significant reduction in the root yield. The species composition of these plants is an important factor influencing the competition with crops. The aim of the 2-year field experiment with mixtures of: phenmedipham + ethofumesate + metamitron + quinmerac; ethofumesate + metamitron + metamitron + + quinmerac + triflusulfuron-methyl; phenmedipham + ethofumesate + metamitron + + quinmerac + triflusulfuron-methyl + clopyralid + lenacil, and phenmedipham + ethofumesate + metamitron + quinmerac + triflusulfuron-methyl + clopyralid applied in split doses, microdoses and Conviso Smart technology was to determine the weed species community composition and effectiveness of weed control strategies. The most common species occurring in both years were: Chenopodium album L., Fallopia convolvulus L., and Geranium pusillum L. The communities had the highest values of biodiversity indices in 2020 and lower values in 2021. There were no statistically significant differences in the herbicidal effectiveness of the tested herbicidal technologies over both years of research and for individual main weed species – 95–99%. The use of all herbicide variants contributed to achieving significantly higher yields than untreated treatments, and contributed to an increase in profitability of cultivation, but this result depended on the selected strategy. The presented herbicide solutions were characterized by direct income at a similar level.

Biochar applications for treating potentially toxic elements (PTEs) contaminated soils and water: a review.

Environmental pollution with potentially toxic elements (PTEs) has become one of the critical and pressing issues worldwide. Although these pollutants occur naturally in the environment, their concentrations are continuously increasing, probably as a consequence of anthropic activities. They are very toxic even at very low concentrations and hence cause undesirable ecological impacts. Thus, the cleanup of polluted soils and water has become an obligation to ensure the safe handling of the available natural resources. Several remediation technologies can be followed to attain successful remediation, i.e., chemical, physical, and biological procedures; yet many of these techniques are expensive and/or may have negative impacts on the surroundings. Recycling agricultural wastes still represents the most promising economical, safe, and successful approach to achieving a healthy and sustainable environment. Briefly, biochar acts as an efficient biosorbent for many PTEs in soils and waters. Furthermore, biochar can considerably reduce concentrations of herbicides in solutions. This review article explains the main reasons for the increasing levels of potentially toxic elements in the environment and their negative impacts on the ecosystem. Moreover, it briefly describes the advantages and disadvantages of using conventional methods for soil and water remediation then clarifies the reasons for using biochar in the clean-up practice of polluted soils and waters, either solely or in combination with other methods such as phytoremediation and soil washing technologies to attain more efficient remediation protocols for the removal of some PTEs, e.g., Cr and As from soils and water.

An autonomous spraying robot architecture for sucker management in large‐scale hazelnut orchards

AbstractIn this work, motivated by the precision agriculture (PA) paradigm, we address the problem of managing hazelnut suckering plants on a per‐plant basis in a large‐scale orchard. Suckering plants, or shortly, suckers, are basal shoots that grow at the base of a tree and compete with the tree itself for nutrients and water. Generally, in large‐scale orchards, suckers are treated with the application of herbicide through spraying tractors that continuously spray the crops while navigating the whole orchard. This approach however does not consider the individual needs of each plant and it is definitely not environmentally‐friendly since a lot of unnecessary solution is being drained in the soil. For this reason, we propose a novel fully autonomous sucker management architecture that is able to detect the presence of suckers for each plant, by relying on a You Only Look Once (YOLO)‐based recognition system, reconstruct them in three‐dimension and estimate the amount of herbicide solution needed for the specific plant, based on a data‐driven approach. The herbicide solution is applied using a ground robot equipped with an RGB‐D camera and a spraying system. This approach allows to significantly reduce pollution and waste. Experimental results both for individual components and for the entire architecture in a real‐world (1:1 scale) hazelnut orchard located in Caprarola, Italy, are provided to corroborate the proposed architecture.

Shifting application dates on cereal reduces pesticide transfer via subsurface drainage based on water flow forecasts during autumn applications.

Thanks to the changes in aquatic risk assessment within the Marketing Authorization (MA) process in France, the contamination of surface water through the subsurface drainage network is better accounted for. The measure adopted by Risk Regulations is to prohibit any use of selected pesticides on drained plots. Herbicide solutions on subsurface-drained plots are becoming scarce due to a limited number of innovations combined with the re-approvals process. Autumn weed management then becomes a major issue for winter cropping systems on drained plots. Unlike runoff prevention, few risk management measures are available to prevent the risks associated with drained plots. We analyzed data from La Jaillière, an ARVALIS experimental site (9 plots, 1993 to 2017), representative of scenario D5 from EU FOCUS Group, for four herbicides (isoproturon, aclonifen, diflufenican, flufenacet). Our study first demonstrates the relevance of the time application management measure by showing the decreasing trend in the transfer of pesticides in drained plots. The second result is to validate, still on the La Jaillière site, the hypothesis of a management measure based on an indicator of soil profile saturation before drainage flow (Soil Wetness Index). A conservative measure consisting in restricting pesticide applications during autumn, when the SWI is < 85% of saturation, reduces the risk by a factor of 4-12 for quantification above the predicted no-effect concentration (PNEC) and values of maximum or flow weight average concentrations (Cmax and CMP) by 70- and 27-fold, ratio of exported pesticide (Rexp) by 20-fold, and total flux by 32. This measure based on SWI threshold appears to be more efficient than those using other restriction factors. SWI could be easily calculated considering local weather data and soil properties for any drained field. This article is protected by copyright. All rights reserved.

Solar photoelectro-Fenton: A very effective and cost-efficient electrochemical advanced oxidation process for the removal of organic pollutants from synthetic and real wastewaters

Recalcitrant and toxic organic pollutants from wastewaters are scarcely removed in conventional wastewater treatment plants. To preserve the water quality, organics need to be removed by developing powerful oxidation technologies. Our laboratory proposed in 2007 a potent electrochemical advanced oxidation process (EAOP) for wastewater remediation, so-called solar photoelectro-Fenton (SPEF). This review summarizes the advances of this emerging technology up to 2022, making evident its effectiveness and cost-efficiency for the destruction of usual organic pollutants. The simultaneous action of generated hydroxyl radicals and the photolysis by sunlight explains the high oxidation power of SPEF respect to other EAOPs. The review is initiated by describing the fundamentals of the process to remark the role of the produced oxidants and the benefits of using solar irradiation in its performance. The photoelectrochemical systems used (bench tank reactor and solar pre-pilot flow plant) and the assessment of the operating variables are discussed. The characteristics of the most common homogeneous SPEF for the degradation and mineralization of several synthetic solutions of industrial chemicals, herbicides, pharmaceuticals, and synthetic organic dyes, as well as of some real wastewaters, are further described. The influence of the photoelectrochemical cell, electrodes, solution pH, electrolyte composition, Fe2+ and pollutant concentration, and current density is analyzed. The performance of a homogeneous SPEF-like process with active chlorine and heterogeneous SPEF processes with solid catalysts such as Fe3O4 and sodium vermiculite is also discussed. Finally, the advances of homogeneous SPEF combined with other techniques like solar photocatalysis, solar photoelectrocatalysis, anaerobic digestion, and nanofiltration are reported.

Efficiency for combinations of rimsulfuron with adhesives in maize crops

Topicality. Adhesives are an integral part of the weed control system in the maize crops, because they increase the efficiency of herbicide application. They significantly reduce the cost of plant protection products and increase their efficiency, as well as increase the adhesive properties of the herbicide solution to prevent its runoff and prolong its action. Development of new herbicides, constant weather and climate changes require to study further the effectiveness of the combined action of herbicides and adhesives. Among the adhesives for maize, it is generated interest such products as Synergent SOC, Eco Oil Spray, Esterlip, etc. Purpose. To reveal the effectiveness for combinations of herbicides with adhesives in the maize crops, as well as their impact on plant growth and development. Materials and Methods. The experimental scheme included the following combinations of rimsulfuron with adhesives: 1. Control (Rimsulfuron without adhesive); 2. Rimsulforon (40 g/ha) + Trend 90 (0.15 % working solution); 3. Rimsulforon (40 g/ha) + Synergent (0.15 % working solution); 4. Rimsulforon (40 g/ha) + Eco Oil Spray (0.15 % working solution); 5. Rimsulforon (40 g/ha) + Esterlip (0.15 % working solution); 6. Rimsulforon (35 g/ha) + Esterlip (0.15 % working solution); 7. Rimsulforon (25 g/ha) + Esterlip (0.15 % working solution). Results. The combination of rimsulfuron with adhesive Esterlip had the highest technical efficiency compared to other adhesives, in particular, on the redroot pigweed (Amaranthus retroflexus L.) was 75–100% (complete destruction) and lamb’s quarters (Chenopodium album L.) – 85.7–92.9 %, slightly less on common ragweed (Ambrosia arte-misiifolia L.) – 83.3%. Common purslane (Portulaca oleracea L.) was highly resistant to almost all combinations of rimsulfuron with adhesives. The highest maize yield of 8.99 t/ha was in the variant with Rimsulfuron (40 g/ha) + Esterlip. Reduced application rate of Esterlip to 25–35 g/ha decreased the maize yield to 7.34–7.65 t/ha, or by 1.34–1.65 t/ha (14.9–18.3 %) due to increased weed infestation of crops. The application of adhesives Trend 90, Synergen, Eco Oil Spray also decreased maize yields to 8.48 t/ha, 8.07 t/ha and 8.62 t/ha, respectively, which was less by 0.51 t/ha (5.6 %), 0.92 t/ha (10.2 %) and 0.37 t/ha (4.1 %). The lowest yield was in the control – 5.30 t/ha due to significant weed infestation of grain crops, which decreased by 3.69 t/ha (41.0 %) compared to the best variant (Rimsulfuron (40 g/ha) + Esterlip). Conclusions. Considering the ongoing development of new adhesives and herbicides for maize, as well as climate changes, it is necessary to continue research in this area to determine the most optimal ratio of herbicide rates with adhesives. Key words: maize, weeds, herbicides, adhesives, yield, technical efficiency

Adjuvant and nozzle effects on weed control using mesotrione and rimsulfuron plus thifensulfuron-methyl

Limitations on the available herbicide portfolio for weed control have led to weed control failures. Application techniques such as proper selection of nozzle types, adjuvants, and herbicide selection have been suggested as one of the ways to maximize efficacy. The launch of HPPD (hydroxyphenylpyruvate dioxygenase)-tolerant crops will increase HPPD herbicide applications, while effective herbicide tank mixtures might prolong herbicide resistance evolution. Therefore, a greenhouse experiment was conducted to evaluate the effects of mesotrione (MES) and rimsulfuron plus thifensulfuron-methyl (RIMTHIF) in tank mixtures with five adjuvants sprayed with three different nozzle types, XR (Extended Range), AIXR (Air Induction Extended Range), and TTI (Turbo TeeJet Induction), on weed control. Five weed species were tested: common lambsquarters (Chenopodium album L.), velvetleaf (Abutilon theophrasti Medic.), common waterhemp (Amaranthus tuberculatus (Moq.) J.D. Sauer), Palmer amaranth (Amaranthus palmeri S. Wats.), barnyardgrass (Echinochloa crus-galli (L.) P. Beauv.), and a grain sorghum (Sorghum bicolor (L.) Moench) crop. A dose‒response study using MES and RIMTHIF was conducted to estimate the effective dose to reduce the aboveground biomass by 50% from the nontreated control (ED50). Another study was conducted to evaluate the efficacy of MES and RIMTHIF in tank mixtures with five adjuvants (ammonium sulfate – AMS, crop oil concentrate – COC, drift reducing adjuvant – DRA, methylated seed oil – MSO, and nonionic surfactant – NIS) sprayed with three nozzle types (XR, AIXR, and TTI). The selected nozzles influenced velvetleaf, common lambsquarters, and sorghum, indicating the possibility of applying herbicides with Coarser sprays, avoiding off-target movement. Our findings suggest adjuvants are an essential factor for improving weed control over the active ingredient, up to 18.7% and 38.3% for MES and RIMTHIF, respectively. Barnyardgrass biomass reduction was greater than 98% with RIMTHIF in tank mixtures with COC and MSO compared to 65% when applied alone. Common lambsquarters had 52.1% biomass reduction when RIMTHIF was sprayed alone, while adding adjuvants to the tank-mixture resulted in biomass reduction ranging from 60.1% (COC) to 94.1% (AMS). Velvetleaf biomass reduction was 98% when the MES and RIMTHIF mixture was applied with the addition of MSO, while 87% without the adjuvant added. These results indicate that adding adjuvants in herbicide solution can improve herbicide efficacy (COC and MSO for barnyardgrass; NIS, AMS, and MSO for velvetleaf; and NIS, COC, and MSO for common lambsquaters).

Enhanced detoxification via Cyt-P450 governs cross-tolerance to ALS-inhibiting herbicides in weed species of Centaurea

Centaurea is a genus of winter weeds with a similar life cycle and competitive traits, which occurs in small-grains production fields in the central-southern of the Iberian Peninsula. However, most of herbicides recommended for weed management in wheat show poor control of Centaurea species. This study summarizes the biology, herbicide tolerance to acetolactate synthase (ALS) inhibitors, and recommended chemical alternatives for the control of Centaurea species. Four species (C. cyanus L., C. diluta Aiton, C. melitensis L. and C. pullata L. subsp. baetica Talavera), taxonomically characterized, were found as the main important broadleaf weeds in small-grains production fields of the Iberian Peninsula. These species showed innate tolerance to tribenuron-methyl (TM), showing LD50 values (mortality of 50% of a population) higher than the field dose of TM (20 g ai ha−1). The order of tolerance was C. diluta (LD50 = 702 g ha−1) ≫ C. pullata (LD50 = 180 g ha−1) ≫ C. cyanus (LD50 = 65 g ha−1) > C. melitensis (LD50 = 32 g ha−1). Centaurea cyanus and C. melitensis presented higher foliar retention (150–180 μL herbicide solution), absorption (14–28%) and subsequent translocation (7–12%) of TM with respect to the other two species. Centaurea spp. plants were able to metabolize 14C-TM into non-toxic forms (hydroxylated OH-metsulfuron-methyl and conjugated-metsulfuron-methyl), with cytochrome P450 (Cyt-P450) monooxygenases being responsible for herbicide detoxification. Centaurea cyanus and C. mellitensis metabolized up to 25% of TM, while C. diluta and C. pullata metabolized more than 50% of the herbicide. Centaurea species showed 80–100% survival when treated with of florasulam, imazamox and/or metsulfuron-methyl, i.e., these weeds present cross-tolerance to ALS inhibitors. In contrast, auxin mimics herbicides (2,4-D, clopyralid, dicamba, fluroxypir and MCPA) efficiently controlled the four Centaurea species. In addition, the mixture of ALS-inhibitors and auxin mimics also proved to be an interesting alternative for the control of Centaurea. These results show that plants of the genus Centaurea found in the winter cereal fields of the Iberian Peninsula have an innate tolerance to TM and cross-resistance to other ALS-inhibiting herbicides, governed by reduced absorption and translocation, but mainly by the metabolization of the herbicide via Cyt-P450.

Particle drift simulation from mesotrione and rimsulfuron plus thifensulfuron-methyl mixture through two nozzle types to field and vegetable crops.

Potential for off-target movements follows every herbicide application. Because the launch of acetolactate synthase (ALS)- and 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicide-tolerant crops will increase the treated area, there is a need to assess the possible negative consequences of any particle drift from those herbicides. Drift happens with every pesticide application, requiring mitigation. Various factors influence drift. Some, such as nozzle type, working pressure, and boom height, can be managed. Others, such as wind, are not easy to manage. In our study, an herbicide tank mixture of mesotrione with rimsulfuron plus thifensulfuron-methyl was sprayed in a low-speed wind tunnel to simulate drift. The airspeed was set at 4.4ms-1, representing the labeled upper limit for applications. The herbicide solution was sprayed through XR110015 and TTI110015 nozzles. Eight crops were exposed to herbicide drift treatments and biomass data were collected. Droplet size spectra and tracer depositions were evaluated. Tracer deposition was on average threefold higher in all downwind distances (0.5, 1, 2, 3, 4, 6, 9, and 12m) from the XR nozzle in comparison to the TTI nozzle. As a consequence, greater biomass reduction was recorded for applications with the XR compared to the TTI nozzle from 1 to 12m downwind. At 12-m distance, biomass was decreased by 7-78% using XR nozzle while 1-27% using the TTI nozzle. Because drift can injure crops, it is very important to mitigate drift from application of formulations containing mesotrione and rimsulfuron plus thifensulfuron-methyl in combination. This can be done by selecting the appropriate nozzle and ensuring optimal distances between crops.

Impact of volatility reduction agents on dicamba and glyphosate spray solution pH, droplet dynamics, and weed control.

Regulations in 2021 required the addition of a volatility reduction agent (VRA) to dicamba spray mixtures for postemergence weed control. Understanding the impact of VRAs on weed control, droplet dynamics, and spray pH is essential. Adding glyphosate to dicamba decreased the solution pH by 0.63 to 1.85 units. Across locations, potassium carbonate increased the tank-mixture pH by 0.85 to 1.65 units while potassium acetate raised the pH by 0.46 to 0.53 units. Glyphosate and dicamba in tank-mixture reduced Palmer amaranth control by 14 percentage points compared to dicamba alone and decreased barnyardgrass control by 12 percentage points compared to glyphosate alone 4 weeks after application (WAA). VRAs resulted in a 5-percentage point reduction in barnyardgrass control 4 WAA. Common ragweed, common lambsquarters, and giant ragweed control were unaffected by herbicide solution 4 WAA. Dicamba alone produced a larger average droplet size and had the fewest driftable fines (% volume < 200 μm). Potassium acetate produced a larger droplet size than potassium carbonate for Dv0.1 and Dv0.5 . The addition of glyphosate to dicamba decreased droplet size from the entire spray droplet spectrum (Dv0.1 , Dv0.5 , Dv0.9 ). A reduction in spray pH, droplet size, and weed control was observed from mixing dicamba and glyphosate. It may be advisable to avoid tank-mixtures of these herbicides and instead, apply them sequentially to maximize effectiveness. VRAs differed in their impacts on spray solution pH and droplet dynamics, but resulted in a minimal negative to no impact on weed control. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Herbicides in unexpected places: non-target impacts from tree root exudation of aminopyralid and triclopyr following basal bark treatments of invasive chokecherry (Prunus padus) in Alaska

AbstractBasal bark treatment of invasive trees is an approach designed to limit damage to non-target vegetation in the vicinity, but non-target injury is still documented. No study of basal bark treatments has examined the release of herbicide residues from roots of treated plants and resulting non-target impacts. Studies were conducted in Alaska interior and coastal boreal forests on basal bark treatments with aminopyralid and triclopyr on active-growth and dormant invasive chokecherry (Prunus padus L.). The study assessed non-target damage and soil herbicide residue using a combination of visual evaluations, bioassays, and soil residue analyses. Non-target damage from herbicide residues were identified in 40% of treatments containing aminopyralid with triclopyr, 60% of treatments containing aminopyralid alone, and 5% of treatments containing only triclopyr. Laboratory studies of aminopyralid treatments to saplings isolated the effects of herbicide exudation from roots, which was found to be significant, and the magnitude was dependent on dose. Herbicide soil residues in field and laboratory experiments were quantified with analytical detection and plant bioassays. Aminopyralid soil residues were identified in 57% of field treatments receiving 8 to 60 ml of herbicide solution (2% ai) and 70% of laboratory treatments receiving 10 µl of herbicide solution (2% to 16% ai). Triclopyr residues were found from one field treatment following dosage with 28 ml of herbicide solution (18.5% ai). Anatomically, plants grown in soils associated with herbicide-treated trees, both in the field and lab, grew less dry mass than non–herbicide treated controls. This study provides the first evidence that root exudation of herbicide following basal bark treatments contributes to non-target damage of adjacent vegetation and to accumulation of soil herbicide residues. This is an important new factor for integrated pest management within basal bark treatment systems and has implications for other herbicide application types such as injections and frill, as well as determining whether root exudation is species or herbicide specific.

Progress in hybrid wheat seed production technologies and implication of herbicide solutions in hybrid wheat purity improvement

<p indent="0mm">Hybrid wheat, potentially offering superior yield potential and yield stability, will play an important role in improving China’s food security. However, the high cost of hybrid seed production limits the adoption of hybrid wheat in China. Hybrid seed production cost is determined by several factors including the yield per unit of area, the purity of hybrid seed, and the seeding rate. Pilot studies have suggested that the seeding rate of hybrid wheat can be reduced by 20%–30% compared with that of traditional inbred varieties. However, the current growing practice in China makes it difficult to convince growers to embrace reduced seeding rate. Therefore, increasing hybrid seed yield and purity becomes more important for reducing the hybrid seed production cost; and particularly increasing the seed purity is a more feasible solution. In this review, hybrid seed production technologies, as well as herbicide solutions for seed purity improvement are summarized. In either a thermo-/photoperiod-sensitive genic male sterile (TGMS/PGMS) based 2-line seed production system or a cytoplasmic male sterility (CMS) based 3-line seed production system, male parents are always planted together with female parents in a certain ratio to provide pollen. Male parents can still produce inbred seeds through self-fertilization, which will reduce the purity of hybrid seeds. Herbicides can be used to terminate male parents or impair the inbred seed development after pollination, leading to an increased hybrid seed purity. However, not all herbicides fit this purpose; in this review, we suggest a set of criteria for selecting existing or developing new herbicides for hybrid seed purity improvement. Accordingly, ALS inhibitors and ACCase inhibitors are two major classes of herbicides that can be tested in wheat hybrid seed production. Glyphosate kills the whole plant when spray at 1 week or 2 weeks after pollination, but dead male plant still can produce few shrunken seeds. Compared to glyphosate treatment, imazethapyr and sethoxydim cannot kill male plants, but can limit selfed seed development. Shrunken seeds can be removed from hybrid seeds based on smaller size and lighter weight. Another novel angle is relying on chemicals/small molecules/ mycoherbicide to boost herbicide efficacy, such as Bobcat339, miR858 and <italic>Pyricularia setariae</italic>. The clues come from several studies, such as <italic>Atros1</italic> loss-of-function mutant is more sensitive to imazethapyr treatment, <italic>Pyricularia setariae</italic> can break sethoxydim resistance in foxtail, etc. Moreover, this review also provides an outlook into some of the new technologies, particularly the clonal seed (apomixis) technology which enables producing selfed hybrid seeds from hybrid seed parent without the need of a separate pollen parent, and thus maximize the yield and purity of hybrid seed production. <italic>SPO11</italic> (or <italic>PAIR1</italic>), <italic>REC8</italic> and <italic>OSD1</italic> are quite conserved among different crops, and <italic>Tamatl</italic>/<italic>pla1</italic>/<italic>nld</italic> mutant is already proved to induce maternal haloid in wheat.

Influence of Broadcast Nozzle Design and Weed Density on Dicamba Plus Glyphosate Deposition, Coverage, and Efficacy in Dicamba-Resistant Soybean

Dicamba injury to sensitive soybean and other broadleaf crops due to drift is a major issue. Dicamba label restrictions have been created to mitigate the off-target movement of dicamba. One restriction is the mandated use of low-drift nozzles to spray dicamba; these nozzles produce large droplet spectrums and minimize the production of driftable fines. Experiments were conducted to evaluate herbicide coverage, deposition, and efficacy as influenced by spray nozzle design and density of waterhemp, goosegrass, and large crabgrass in dicamba-resistant soybean. Dicamba plus glyphosate was applied to 5- to 10-cm-tall weeds with a Turbo TeeJet (TT11005) nozzle and two drift reduction nozzles approved for dicamba applications: Turbo TeeJet Induction (TTI11005) and Pentair Ultra Lo-Drift (ULD12005). Weed densities were categorized into different levels and established in a 0.25-m2 quadrat prior to postemergence application. Deposition of herbicide spray solution onto targeted weeds was not different despite coverage differences observed on Kromekote spray cards. Coverage of herbicide solution was consistently lower with the low-drift TTI11005 nozzle as compared to the TT11005 nozzle. Herbicide efficacy on waterhemp plants was the lowest at the highest waterhemp densities of 54 plants per m2 with the drift-reducing TTI11005 nozzle, although weed control was not lowered at any density when applications were made with the ULD nozzle as compared to the TT11005 nozzle. Additionally, herbicide efficacy was reduced as large crabgrass density increased. Overall, the use of a drift-reducing nozzle can be successful for waterhemp control and Poaceae control postemergence in soybean when weed densities are suppressed or reduced through methods such as the use of a residual preemergence herbicide or cereal rye cover crop.

Use of superoxide dismutase activity indicator in the system of surface water ecological monitoring

The usage of herbicides is increasingly spreading both in the world and in Ukraine. Constant monitoring of this type of the polluting substances is one of the areas for maintaining the ecological security. It is significant for diverse environmental objects, especially for the surface water sources. Contemporary herbicides have a wide range of various mechanisms of action. In this regard, applied methods have to ensure the high level of sensitivity and reasonable specificity for measuring the excessive concentrations of herbicides in the environment. Besides, it is considerable to choose appropriate test organisms. They have to satisfy the list of requirements, while the most important one is that it would be a hydrophyte that has full contact with water. Therefore, the Elodea canadensis Michx. has been chosen by us as a test object. This species is a cosmopolitan and is widely used for the bioassay procedure.&#x0D; The system of biochemical transformations is one of the most sensitive links for the maintenance of the cell homeostasis. Typically, enzymes react to the stress-induced variation in environmental situation by modification of their activity. Consequently, this fact is used for the stress assessment of the organism. We have offered to measure the enzymatic activity of superoxide dismutase (SOD) as the most remarkable system biomarker on the toxic impact of the herbicides. The main function of SOD is the prevention of the growing oxidative stress in the cell. Thus, it can serve as an integral index that acts on the influence of varied chemical substances.&#x0D; For this reason, the aim of the research paper is to indicate the specific changes in the SOD activity of the Elodea canadensis’ cells in conducting the bioassay of the herbicides of varied groups. &#x0D; The aim was achieved through the investigation of the dynamical changes in the SOD activity of Elodea canadensis. The water plant had contact with varied groups of the herbicides in different concentrations.&#x0D; As a result, we have discovered the high sensitivity of the SOD activity of Elodea canadensis while being immersed into water with different herbicides. Hence, this test can be recommended for use to determine the contamination of water with pesticides.&#x0D; We recommend using a one-day experiment for the most representative results to explore the dynamical changes in the enzyme activity of elodea in herbicide solution. &#x0D; The elaborated bioassay method has the following advantages: quickness, accessibility and sensitivity. The absence of the specificity in similar studies can refer to disadvantages. Howsoever, it can also refer to advantages if the screening is conducted for a wide range of contaminations.

Impact of glyphosate formulations and adjuvants: effects on leaf interaction, metabolism, and control of sourgrass

ABSTRACT: The addition of commercial formulations and adjuvants to a tank mix may result in differences in the wettability on the plant surface, foliar uptake and herbicide efficacy. Thus, the objectives of this study were to evaluate the influence of glyphosate formulations and tank-mixture adjuvants on the contact angle (CA), uptake, metabolism and sourgrass control and the damage to the cuticular microstructure of this species caused by herbicide solutions. For this purpose, assays were carried out in a completely randomized design, and treatments distributed in a 2x5+1 factorial scheme with five replications. Two glyphosate formulations isopropylamine salt (SL) and ammonium salt (WG) combined or not with the adjuvant methylated soybean oil (MSO), mineral oil (MO), ethoxylated alkyl ester (EAE) or polyoxyethylenealkylphenol ether (PAE); and one control (water) were evaluated. CA measurements of the droplets deposited on a sourgrass leaf surface and on the standard surface (parafilm) were obtained using a tensiometer. Herbicide uptake and shikimate accumulation were simultaneously determined by chromatography and spectrometry. The control effect was assessed by observing plant survival dry weight reductions. The glyphosate SL and WG formulations had similar effects on the variables analyzed. However, mixing the adjuvants EAE, MO or MSO with either formulation of herbicide led to greater wettability and more severe damage to the cuticular microstructure, favoring glyphosate uptake and shikimate accumulation. Despite evidence regarding the treatments containing oils/surfactants, the control effect on sourgrass was similar. The combination of glyphosate formulations with such adjuvants is potentially more effective and guarantees satisfactory sourgrass control.