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ALS-resistant weeds are of major importance in many European agriculture systems. Resistant biotypes showed up in more weed species, more regions and in more crops. Therefore, every method or tool to control weeds, that potentially increases the selection pressure on herbicides and weeds must be handled with care. On the other hand new tools like herbicide tolerant varieties offer new possibilities for weed control. Particularly in sugarbeet, chemical weed control is still a compromise between efficacy and crop selectivity today. ALS-tolerant varieties offer the opportunity to improve crop safety and efficacy. To investigate the influence of these sugar beet varieties on the dynamic of ALS-resistant weed populations in a three-year crop rotation, a six-year field trial was conducted on two experimental sites. Four different weed control strategies were tested, which exhibit different levels of selection pressure to ALS inhibitors. The field trial showed that continuous use of ALS herbicides quickly increased the density of resistant weed populations leading to a large yield reduction. However, this process was much slower, when the frequency of ALS inhibitor use was reduced. Yet, it was not stopped completely. Even the use of alternative modes action was only partly able to slow down the resistance evolution. While weeds resistant to ALS herbicides only could be well controlled, multiple resistant weeds were able to build up a new resistance mechanism (ACCase inhibitor resistance). Here this was the case for Alopecurus myosuroides. As a consequence, use of alternative MoAs failed to control A. myosuroides. Due to these complex interactions sustainable use of herbicide tolerant varieties is not easy in the long run. Advantages might be long lasting when site-specific resistant weed status is adequately addressed.

Durch den Wegfall von herbiziden Wirkstoffen wie Deiquat als Sikkationsmittel im Frühkartoffelanbau oder dem potenziell bevorstehenden Wegfall von Glyphosat rücken alternative Verfahren in den Vordergrund. Ein möglicher Ansatz ist die ElectroherbTM Technologie der Firma Zasso®, welche auf einem nichtselektiven, systemischen, elektrischen Fluss durch das Gefäßsystem der Pflanzen beruht, der die Zellstrukturen zerstört. Zur Eignungsprüfung in der Sikkation in Frühkartoffeln und zur Bekämpfung von ausdauernden Unkräutern wurde das Verfahren am Standort Bingen 2020 und 2021 getestet. Neben verschiedenen Fahrgeschwindigkeiten (1, 3 und 6 km/h) wurden Kombinationen aus chemischen bzw. mechanischen Verfahren mit der ElectroherbTM Technologie zur Krautsikkation getestet. Bei den ausdauerenden Unkräutern (Cirsium arvense, Elymus repens, Rumex obtusifolius) wurde lediglich die Fahrgeschwindigkeit variiert (1, 3 und 6 km/h). Im Versuchsjahr 2020 wurde in allen behandelten Kartoffel- Varianten ein Absterbegrad von Blatt und Stängel von 100 % nach spätestens 14 Tagen bonitiert. In 2021 wurden in den reinen elektrophysikalischen Varianten Wirkungsgrade von 80 bis 90 % erzielt, was an feuchteren Bedingungen und einem stärkeren Krautwachstum lag. Die perennierenden Unkräuter zeigten eine hohe Wirkung auf den Spross von bis zu 100 %, jedoch trieben alle Arten in 2021 vier Wochen nach der Behandlung wieder aus, in 2020 war dies nur bei E. repens der Fall. Neben der Geschwindigkeit scheint die Bodenfeuchte zur Zeit der Applikation die Wirksamkeit zu beeinflussen. Durch die geringere Flächeneffizienz und zusätzliche Anschaffungskosten sind höhere Verfahrenskosten bei der Bewertung zu berücksichtigen. Zur umfänglichen Bewertung des Verfahrens fehlen noch Erkenntnisse –unter verschiedenen Einsatzbedingungen und zu potenziellen Nebenwirkungen.

Environmentally friendly and resource-saving cultivation, sustainability and regionality are important aspects of today's agriculture. Reducing the use of herbicides is considered one of the most important goals and at the same time one of the biggest challenges in today's agriculture. In viticulture, however, the alternative management options are also under discussion. The aim of this study is to analyze and test the Electroherb method developed by the company ZASSO GmbH. In three-year field experiments, vegetation monitoring and digital image analysis will be used to investigate the degree of coverage before and after treatment, as well as the effectiveness of the process on various problem weeds. Special attention will be paid to the vegetation in the under-floor area of the vine. In addition to the current intensity and driving speed, the number of treatment sessions will be investigated. Preliminary results show that the morphology of the weeds plays a decisive role in the efficiency. Weather and water supply are also important influencing factors.

The focus of the public demand for sustainable and resource-conserving agriculture is the reduction of herbicide use. However, successful weed control is essential to ensure crop yield and quality. Today's agriculture is confronted with the challenge of finding suitable crop management alternatives. In the present study, the Electroherb™ technology developed by the Zasso Group AG is investigated. The process is based on a non-selective, systemic electrical flow through the plants' vascular system causing severe cell destruction and ultimately wilting, as mode of action. However, aspects of the effect on non-target organisms must also be considered when evaluating this promising technology. The study investigates the effects of electro-physical weed control on soil organisms. Population densities of earthworms and epigeic arthropods are recorded. Parameters such as speed at application, soil moisture, energy intensity and application timing were investigated. No effects of the electrical treatment on earthworm abundance and biomass were detected. In addition, there was also no evidence of adverse effects on soil organisms. Electro-physical weed control could be an environmentally friendly, sustainable, soil-friendly and innovative way to control weed species, provided that the effects on soil organisms are acceptable when electrophysical voltage is applied.

Mit drohenden Indikationseinschränkungen von Glyphosat im Ackerbau und dem eventuellen mittelfristigen Wegfall des Wirkstoffes stellt sich die Frage, wie und ob Mulchsaatsysteme von Sommerungen aufrechterhalten werden können. Am Beispiel von Zuckerrüben werden Ergebnisse aus drei Feldversuchsjahren präsentiert, in denen die Wechselwirkungen von Zwischenfrüchten und Bodenbearbeitungssystemen auf die Unkrautpopulationen und die Zuckerrübenetablierung aufgezeigt werden. Es wurden je nach Standort 12 bis 35 Systeme in 2 bzw. 4 Wiederholungen geprüft. Die Ergebnisse fallen sehr unterschiedlich aus. Je nach Jahreswitterung, Bodenbearbeitungssystem, Zwischenfrucht und Herbizideinsatz kann eine Zuckerrübenmulchsaat ohne Glyphosateinsatz sehr gut funktionieren aber auch scheitern. In vielen Fällen bedeutet ein Glyphosatverzicht einen deutlich höheren Aufwand an Bodenbearbeitung und teilweise auch einen zusätzlichen Einsatz von Herbiziden.

Das Vorkommen von Herbizidresistenzen bei Ungräsern nimmt in den letzten 30 Jahren in Deutschland kontinuierlich zu. Dies gilt sowohl für die Anzahl der betroffenen Arten, die regionale Verbreitung, den Resistenzgrad, die Anzahl der Aktivsubstanzen, der Wirkstoffklassen und damit die betroffenen Herbizide. Der Beitrag zeigt anhand von Gewächshausbiotestergebnissen von 1197 Acker-Fuchsschwanz- und 737 Windhalmproben die Entwicklungen sowie den aktuellen Status Quo auf. Deutlich wird die Verschärfung der Entwicklung im Bereich der Nachauflaufherbizide mit Blattaktivität insbesondere bei A. myosuroides und die Zunahme der ALS-Herbizidresistenzen bei A. spica-venti. Die Frequenz von wirkstoffklassenübergreifenden Kreuzresistenzen nimmt zu. In der Folge können viele Acker-Fuchsschwanz- und einige Windhalmpopulationen im Nachauflauf nicht mehr mit selektiven Herbiziden kontrolliert werden. Die Situation wurde im Untersuchungszeitraum 2006 bis 2018 stetig deutlicher und zeigt, dass das Ausmaß an Änderungen in den Ackerbausystemen aktuell noch nicht ausreicht den Trend zu stoppen. Dadurch wird die Produktivität des gesamten Ackerbaues gefährdet, der Herbizideinsatz tendenziell erhöht und damit auch der Selektionsdruck eher verstärkt statt, wie notwendig, abgesenkt.

Hühnerhirse (Echinochloa crus-galli) gewinnt als Ungras im Maisanbau zunehmend an Bedeutung. Einseitiger Einsatz von ALS-Inhibitoren erzeugt einen Selektionsdruck, der zu vermehrtem Auftreten von Resistenzen führt. Häufig handelt es sich um Target-Site-Resistenzen (TSR) mit Punktmutationen an den Positionen Ala-122, Pro- 197 oder Trp-574 des ALS-Gens. Dieses liegt in der hexaploiden Hühnerhirse in drei homologen Varianten vor. Gängige PCR-Verfahren ermöglichen nur eine gemeinsame Analyse aller Genvarianten, wodurch ein großer Teil des Informationsgehalts verloren geht. Für eine fundierte Aussage müssen die Genvarianten getrennt analysiert werden. Ein methodischer Ansatz war die allel-spezifische PCR. Hierfür wurden DNA-Polymorphismen zwischen den drei ALS-Genvarianten genutzt, um diese separat bei Position 574 hochspezifisch zu amplifizieren und zu sequenzieren. Die schwierige Struktur und geringe Polymorphismen verhinderten den Einsatz der allelspezifischen PCR an den Positionen 122 und 197. Hier wurden die drei Genvarianten gemeinsam amplifiziert und anschließend in einem mehrstufigen Ansatz mit Restriktionsenzymen spezifisch verdaut. Nach Separation, Aufreinigung und Reamplifikation der Fragmente wurden die einzelnen Genvarianten durch Pyrosequenzierung analysiert. So konnten an Position Ala-122 in allen ALS-Homologen heterozygote Mutationen nachgewiesen werden, bei Pro-197 und Trp-574 dagegen heterozygote bzw. homozygote Mutationen nur bei ALS3. Durch die Etablierung dieser Methoden können nun Resistenzmuster in Populationen von Echinochloa crus-galli detaillierter untersucht und wichtige Daten zu deren Ausbreitungsdynamik gewonnen werden.

The application of imazamox as an herbicide in oilseed-rape got possible due to the introduction of Clearfield oilseed-rape varieties which are tolerant to ALS inhibitors. The question of this investigation was, if the broader use of ALS-inhibitors increases the selection pressure on herbicide resistant weeds and increases their occurrence in the crop rotation. An outdoor container trial with 30 containers (350 l, 0,7 m²) was performed, starting in autumn 2011. A winter wheat – oilseed-rape rotation was simulated for four years. Three different black-grass biotypes with different resistance pattern and 5 different herbicide programmes were analysed in this study in order to investigate the population dynamics of target-site resistance (TSR) and the development of metabolic resistance. The trials showed interactions between the black-grass biotype and the herbicide strategy on the increase of the black-grass density. There was no interaction due to the use of propyzamide. The frequency of target-site resistance to ACCase inhibitors increased for the corresponding biotypes independently of the herbicide strategy during the trial period. The low frequency of ALS-TSR at trial start did not change during the trial period, independently of the use of imazamox in the oil-seed rape cultivation. The comparison of the resistance factors between the original biotypes and the seeds harvested after the four year container trial showed increasing resistances against pinoxaden for all biotypes. Within the different black-grass biotypes there was a slightly decrease as well as an increase in imazamox efficacy observed. There was no significant increase of meso- + iodosulfuron resistance compared to the original biotypes from 2011 caused by different herbicide treatments. The results indicated that the integration of imazamox tolerant oilseed rape in winter wheat crop rotations did not necessarily increase the development of herbicide resistant black-grass.

The evolution of herbicide resistance is an important topic in plant protection and agricultural practice. Safeners are commonly used in herbicides to protect crops against herbicidal damage. Although no effect on the weed control is expected, it has been theorized that the rate of evolution of non-target site resistance (NTSR) in weeds in cereals may be enhanced by use of herbicide products containing safeners. One of the most important safeners in cereals is mefenpyr-diethyl. Therefore, the possible influence of mefenpyr on herbicide resistance was studied in cooperative trials between Bayer CropScience (BCS, F-Höchst) and FH Bingen. The trials tested in parallel different herbicide resistant black-grass (Alopecurus myosuroides (Huds.)) biotypes under greenhouse conditions. The biotypes where chosen due to known NTSR against Atlantis WG® (4 highly resistant and 5 moderately resistant) as well as two susceptible biotypes. The populations were treated with the following three herbicide/safener regimes in six concentrations adjusted according to the anticipated biotype resistance levels. (1) mesosulfuron + iodosulfuron + without safener formulation, (2) mesosulfuron + iodosulfuron + constant mefenpyr concentration (45g/ha), (3) mesosulfuron + iodosulfuron + varying mefenpyr concentrations (ratio 5:1:15). The treatments were applied in post-emergence based on mesosulfuron to iodosulfuron ratios in Atlantis WG® (5:1). The trials were assessed visually (% effect) and by fresh weight. Dose-response curves were performed and ED50 values for each treatment and biotype were calculated. Results showed a varying effect of safeners which was in the most cases negligible. Depending on the biotypes mostly no impact on the safener was found for herbicide resistance. In conclusion, the trials from Bingen and F-Höchst gave evidence, that there is no significant and consistent influence of the safener mefenpyr on evolution of NTSR black-grass.

In the summer of 2014, panicles from loose silky-bent grass (Apera spica-venti) were collected at 109 sites across the federal state Hessen, to analyze the level of loose silky-bent grass resistance against herbicides from HRAC-class A, B and F1/K3. Panicles from established spraying windows as well as panicles from A. spica-venti patches, which were identified at time of harvest within cereal fields, were included into the monitoring. In December 2014 the loose silky-bent grass seeds were seeded into pots and placed in the greenhouse of plant protection service Hessen in Wetzlar. The young seedlings were sprayed (repeated) with herbicides from HRAC group A, B and F1/K3 at BBCH-stages which provided optimal efficacy for each individual herbicide. Efficacy was rated. Each biotype was tested for well-known mutations, which modify the amino acid sequence of acetolactate-synthase (ALS). Biotypes, in which the herbicide from HRAC group A reached low efficacy, were tested for well-known mutations in the acetyl coenzyme a carboxylase (ACCase) gene. The treatments with the herbicide from HRAC group F1/K3 reached very high efficacy up to 100% in nearly all biotypes. The herbicide treatment with an herbicide from HRAC group A reached high efficacy in most cases. However, all herbicides from HRAC group B showed very low efficacy. Only 12 biotypes could be controlled with an efficacy of more than 90%. 45 biotypes contained several mutations in the ALS gene, which cause ALS-resistance. Only one biotype contained a mutation, which can cause ACCase resistance. These results will be used to study reasons for development of resistance in order to develop guidance information to prevent further increase of resistance.

Camelina (Camelina sativa (L.) Crtz.) is a cruciferous plant. As an oilseed crop camelina is mainly grown for oil production. After the 1960s, however, the cultivation has become less important. Only in recent years, interest in this culture was awakened in the search for new sources of omega 3 fatty acids, natural antioxidants and a potential crop for the production of biofuels. The use of camelina oil for different purposes within the framework of the material use of renewable raw materials is of particular interest due to the high levels of linoleic and linolenic acid. For the establishment of camelina as a crop in agricultural crop rotation systems weed control should not be disregarded despite the rather good competitive ability against weeds. Based on greenhouse experiments a field trial in 2015 with different herbicide strategies was carried out. Besides Butisan Top (metazachlor + quinmerac), Devrinol FL (napropamide) and Stomp Aqua (pendimethalin) and also Betasana SC (phenmedipham) has been tested in various amounts and combinations. Using assessments to weed density and herbicide tolerance different herbicide strategies were compared with each other. Though, it is difficult to find a compromise between satisfactory herbicidal effect and a slight injury to the crop plant. The herbicide selection, the application rate and the combination of different herbicides have an effect on the crop. To confirm the data obtained further tests are necessary.

In monitoring trials investigating the occurrence and spread of herbicide resistance in German and Swiss Lolium populations 26 samples could be included since 2008. Biotypes which showed resistance to postemergence herbicides were included into a detailed greenhouse trial in 2014. Based on dose-response experiments, resistance factors and cross resistance patterns for cycloxydim, flufenacet, glyphosate, iodosulfuron, meso- and iodosulfuron, pinoxaden and pyroxsulam could be determined. Resistance to ALS as well as ACCase inhibitors was found. In a few cases also resistance to flufenacet could be detected. In contrast, no resistance to glyphosate was discovered. Resistant populations were found in four German federal states (Hessen, Mecklenburg-Vorpommern, Sachsen and Schleswig-Holstein). Two populations were resistant to all cereal selective post-emergence herbicides and to flufenacet. Some populations from Switzerland indicated presence of ACCase inhibitor resistance. In the future, more problems with herbicide resistant Lolium species as weeds in cereals may arise due to limited amount of available selective herbicides and climatic change with more favourable conditions for Lolium spp. as weeds.

Agriculture today is facing the challenge to both keeping the input of herbicides into nature at a low level and aiming for high yields while avoiding low efficacies caused by resistance evolution. Taking all this into consideration, results from three years of field-trials in winter cereals with ACCase and ALS inhibitors are presented. In season 2012/13 seven trial-sites with 21 herbicide-treatments could be harvested. In 2013/14 it were six sites with 22 treatments and 2014/15 five sites with 15 treatments. In all herbicide treatments four to six different doses were applied that varied between 6.25 and 100% of the maximum registrated dose. The results from the three years show that the parameter yield is less sensitive compared to the parameter efficacy. The amount of herbicide could be reduced by up to 50% in the average of the three trial years without a significant influence on yield. However, at low dosages a certain amount of weed infestation was tolerated. Consequently, risk of selecting resistant plants might be higher with increasing population densities. In field trials with blackgrass (Alopecurus myosuroides; ALOMY) or loose silky-bent grass (Apera spica-venti; APESV) it could be shown that 48 to 68% of registrated herbicide dose was necessary to secure yield. However, to reach 95% efficacy on average 61 to 76% of the registrated herbicide dose was needed. Consequently, there is a potential for reduction of herbicide dose. To realize this potential, there is a need for describing the site specific influences of environmental factors on herbicide performance.

In field trials in was investigated, if the use of the in Germany new active ingredient imazamox enlarge the possibilities of post emergence weed control in soybeans. Furthermore new herbicide strategies were tested on efficacy and selectivity in soybeans. The use of imazamox was very selective and showed a relative broad spectrum of controlled weed species. However, efficacy of imazamox must be supported by a pre-emergence treatment and in most cases by a tank mix partner. For example cleavers (Galium aparine) can not be controlled by imazamox. Tankmixtures of imazamox and bentazon indicated an antagonism. Efficacy to some weed species was reduced compared to solo application. The low dose concept – three applications of low doses at cotyledon stage of weeds led to some success. However, these strategies must be further investigated, before they can be recommended to commercial farming practice. All herbicide strategies tested showed some surviving weed species. This indicates that choice of herbicides, dose rates and application strategies must be done very careful and site specific.

Winter oilseed-rape was the most common crop in Western Europe where no ALS-inhibitor was used. Due to the introduction of Clearfield winter oilseed-rape varieties the use of ALS-inhibitors also in oilseed-rape is possible. If the broader use of ALS-inhibitors increases the selection pressure on herbicide resistant weeds and increases their occurrence in the crop rotation is the question of this investigation. Therefore, an outdoor container trial (á 350 l, 0.7 m²) was performed starting in autumn 2011. A typical crop rotation of winter wheat/oilseed-rape/winter wheat was simulated in the following three years. Three different black-grass biotypes with characterised resistance pattern and 5 different herbicide programs were analysed. The blackgrass biotypes showed different target-site resistance against ACCase- and/or ALS-inhibitor, as well as metabolic resistance. Before and after each treatment the numbers of black-grass plants per container were counted. Also the numbers of heads were counted before harvest. Additionally genetic analysis due to PCRs and pyrosequencing of ten survivors per container and year were performed. Till now results of the winter wheat and oilseed-rape cultivation were obtained. Herbicide efficacy was between 77 and 98% for the treatments during the winter wheat cultivation. The genetic analysis showed nearly similar portion of TSR in the black-grass populations when compared with the initial frequencies. Only one container showed no TSR. The comparison of the herbicide programs sprayed during the oilseed-rape cultivation showed the best results for all black-grass biotypes for the application of: Metazachlor + dimethenamid (BBCH 09/10), imazamox + quinmerac + Dash (BBCH 14) and propyzamide (BBCH 21/22).

A transcriptomics approach was chosen in order to determine candidate genes for metabolic herbicide resistance in a quantitative comparison of expressed genes in sensitive wild type and resistant blackgrass (Alopecurus myosuroides = ALOMY) plants. Firstly a reference transcriptome for blackgrass was established by means of a paired-end RNA-Seq protocol prepared from control and herbicide treated plants from a metabolic resistant biotype. Secondly gene expression was measured in different metabolic resistant ALOMY biotypes and a representative selection of sensitive wild type plants using a 3´-specific RNA sequencing strategy and related to the reference transcriptome. By comparing expression levels for individual genes in wild type and resistant blackgrass biotypes candidate genes from the group of glutathione transferases were identified. Further analyses will be necessary in order to verify a close correlation with the metabolic resistance.

In an outdoor container trial with different resistant black-grass biotypes with enhanced metabolism, efficacy of pre- and post-emergence treatments as well as their sequence was investigated in spring wheat. Weed control success was compared to a susceptible biotype. Results indicate that there are strong interactions between herbicide and black-grass biotypes. As a consequence site specific herbicide strategies corresponding to current herbicide resistance situation can be necessary. If further trials support these findings than it is essential to characterize the site specific herbicide resistance situation and the potential interactions between different biotypes x herbicides resp. sequences. Only under these circumstances it is possible to optimize the herbicide choice on a specific site. Black-grass control might be optimal than and further speed of resistance evolution might be reduced on that site.

When adjuvants are used as a partner for herbicides in tank-mixtures, they can have a positive influence on herbicidal efficacy in certain situations. The addition of adjuvants can contribute to an enhanced effect of the herbicide when applying the maximum registered dose or when securing weed control of reduced application rates. The influence of adjuvants depends on weather factors, the herbicide partner and the particular weed species. This study examined the influence of different herbicide-adjuvant-combinations on various weed species. The objective of the study was to clarify, if the addition of an adjuvant to a herbicide leads to comparable results within the examined weed species or if the influence of an adjuvant use varies. The determination of relative adjuvant effects allowed comparisons of the data. The influence of six herbicideadjuvant-combinations on six weed species was evaluated in greenhouse trials. All herbicides used were from the group of ALS-inhibitors (HRAC-group B). Data of the greenhouse experiments were compared to results from field trials, which were conducted at five sites in Rhineland-Palatinate. One herbicide with and without an addition of an adjuvant was applied per site. Data of the studies reveal that the use of adjuvants results in a positive influence on herbicidal efficacy in most cases. However, strong differences in intensity as well as quality of adjuvant effects regarding the response of different weed species were observed. The efficacy of the herbicide BIATHLON® for example was improved by addition of an adjuvant for Galium aparine by a factor 364.56. For Daucus carota this factor was 2.98. Growers should necessarily take account of these differences when using adjuvants, especially when they are used to secure reduced application rates.

Resistances in weeds for PS-II herbicides are well known. Since the end of the 1970s especially resistances to triazines in maize represented a problem. Today, because of the variety of alternative active ingredients in maize, this problem is considered to be solved. This is different in sugar beet and potatoes because hardly any new herbicides have been developed during the last 20 years. Chenopodium album is a major weed in all summer crops. In maize, resistance to triazines (target-site resistance (TSR) at position 264 on the D1 protein) is known. In recent years, new TSR in C. album (position 251 in Sweden and 218 in Lower Saxony, Germany) has been found. These biotypes exhibit resistances to triazinones and chloridazon but showed no cross-resistances to triazines. An outdoor pot trial with sugar beets and potatoes showed that higher dosages of ethofumesate in sugar beets and aclonifen in potatoes are able to control triazine and triazinone resistant C. album biotypes to certain extend or even completely, respectivly. A competition pot trial with maize and different C. album biotypes showed no significant differences in weed fitness concerning the parameters plant height, biomass and seed production.

Due to a higher proportion of oilseed rape (Brassica napus) in sugar beet rotations, volunteer oilseed rape can occur in increased numbers in subsequent crops. The sulfonylurea triflusulfuron is widely used for broad-leaved weed control in sugar beet, but may no longer be effective to control imidazolinone-tolerant volunteers when imidazolinone-tolerant oilseed rape is grown, which is due to a cross-tolerance to ALS-inhibiting herbicides. Aim of the study was to evaluate six different herbicide strategies for the control of tolerant volunteer oilseed rape. As a result, imidazolinone-tolerant oilseed rape showed a distinctive cross-resistance to triflusulfuron in the field. Mean herbicide efficacy was 14 % and was only slightly increased by combination with metamitron. Imidazolinone-susceptible and -tolerant oilseed rape varieties showed different response to the herbicide treatments. A significantly higher reduction of plant fresh mass (shoot) > 90 % was caused by herbicide treatments that included the active ingredients desmedipham, phenmedipham, ethofumesate, chloridazon and quinmerac. The results showed that triflusulfuron is no longer suitable to control volunteers if they are derived from imidazolinone-tolerance expressing varieties. However, alternative herbicides are available. Generally, increased attention has to be paid to volunteer management within the whole crop rotation if imidazolinonetolerant oilseed rape is grown. Appropriate tillage strategies after oilseed rape harvest have to be followed by effective herbicide treatments in the subsequent sugar beet, for example a mixture of metamitron, phenmedipham, desmedipham, ethofumesat and lenaciel.

Weeds are a major factor for yield losses in crop production. They compete with the crop for limiting factors such as space, nutrients, water and light. Crop plants themselves can occur as weeds in crop rotations (e.g. oilseed rape). In general, volunteer oilseed rape in cereals is successfully controlled by acetolactate synthase (ALS) inhibitors. When growing Clearfield® oilseed rape, the control of volunteer oilseed rape plants must be adjusted towards their ALS-tolerance. In the present study, the influence of different oilseed rape densities on yield and quality parameters of spring- and winter wheat was investigated. Significant negative correlations were detected for the parameters heads/m2, hectoliter weight and yield. The moisture content and the dockage were subjected to a positive correlation. Based on a non-linear regression analysis, even an infestation with one volunteer plant/m2 resulted in a possible yield loss of 0.74 to 1.61 %. We conclude that an adjustment of the herbicide regime along with good farmers’ practice (harvest date of oilseed rape, harvest technique, mechanical volunteer control, crop rotation) result in a successful volunteer control. Oilseed rape volunteers in general and Imidazolinone-tolerant volunteers in special will have no relevant impact on yield of subsequent cereals accordingly.

SARS-CoV-2 mRNA vaccines induce robust anti-spike (S) antibody and CD4+ T cell responses. It is not yet clear whether vaccine-induced follicular helper CD4+ T (TFH) cell responses contribute to this outstanding immunogenicity. Using fine-needle aspiration of draining axillary lymph nodes from individuals who received the BNT162b2 mRNA vaccine, we evaluated the T cell receptor sequences and phenotype of lymph node TFH. Mining of the responding TFH T cell receptor repertoire revealed a strikingly immunodominant HLA-DPB1∗04-restricted response to S167-180 in individuals with this allele, which is among the most common HLA alleles in humans. Paired blood and lymph node specimens show that while circulating S-specific TFH cells peak one week after the second immunization, S-specific TFH persist at nearly constant frequencies for at least six months. Collectively, our results underscore the key role that robust TFH cell responses play in establishing long-term immunity by this efficacious human vaccine.

Cross-reactive αβ T cell receptors (TCRs) recognizing multiple peptide variants can provide effective control of rapidly evolving viruses yet remain understudied. By screening 12 naturally occurring influenza-derived HLA-B*35:01–restricted nucleoprotein (NP)418–426 epitopes (B*35:01-NP418) that emerged since 1918 within influenza A viruses, including 2024 A/H5N1 viruses, we identified functional broadly cross-reactive T cells universally recognizing NP418 variants. Binding studies demonstrated that TCR cross-reactivity was concomitant with diminished antigen sensitivity. Primary human B*35:01/NP418+CD8+ T cell lines displayed reduced cross-reactivity in the absence of CD8 coreceptor binding, validating the low avidity of cross-reactive B*35:01-NP418+CD8+ T cell responses. Six TCR–HLA-B*35:01/NP418 crystal structures showed how cross-reactive TCRs recognized multiple B*35:01/NP418 epitope variants. Specific TCR interactions were formed with invariant and conserved peptide-HLA features, thus remaining distal from highly varied positions of the NP418 epitope. Our study defines molecular mechanisms associated with extensive TCR cross-reactivity toward naturally occurring viral variants highly relevant to universal protective immunity against influenza. Editor's summary: CD8 T cells mount adaptive immune responses against influenza virus, but how well these T cells detect different influenza variants via recognition by αβ T cell receptors (TCRs) is not fully understood. Quiñones-Parra et al. identified broadly cross-reactive CD8 T cells in healthy human participants or individuals infected with H1N1 2009 influenza virus through a screen of HLA-B*35:01–restricted influenza nucleoprotein (NP)418–426 epitopes (B*35:01-NP418) derived from naturally emerging influenza viruses spanning from the 1918 pandemic influenza A strain to 2024 A/H5N1 and bovine viruses. Broad cross-reactivity came at the expense of antigen sensitivity. TCR interactions occurred with highly conserved or invariant resides of the peptide-HLA complex and not at more varied amino acid positions in the NP418 epitope. These findings provide insight into the extent of TCR cross-reactivity toward influenza variants that contribute to protective responses. —Christiana N. Fogg [ABSTRACT FROM AUTHOR]

T cell activity is governed by T cell receptor (TCR) signaling and constrained by immune checkpoint molecules, including programmed cell death protein 1 (PD-1), cytotoxic T lymphocyte–associated antigen 4 (CTLA-4), and lymphocyte activation gene 3 (LAG-3). The basis for how LAG-3 binds to human leukocyte antigen class II molecules (HLA-II) remains unknown. Here, we present the 3.4-angstrom crystal structure of a LAG-3–peptide–HLA-II complex and probe the energetics of the complex interface. Coincident with the HLA-II binding site of the ancestrally related, monomeric CD4 receptor, the LAG-3 homodimer laterally engages two HLA-II molecules via distal D1 domain surfaces, imposing a 38° angular offset. The LAG-3–HLA-II interface is discontinuous and lacks involvement of the D1 extra loop, a binding site for anti–LAG-3 therapeutic monoclonal antibodies. Upon HLA-II binding, intrinsically mobile loops of the LAG-3 molecule become ordered, with contact residues highly conserved across HLA-DR, DQ, and DP allomorphs. Our data provide a structural foundation for development of immunomodulatory approaches targeting LAG-3. Editor's summary: Lymphocyte activation gene 3 (LAG-3) is an important immune checkpoint receptor on T cells currently being targeted for cancer immunotherapy. LAG-3 is evolutionarily related to CD4 and shares with it the ability to recognize MHC-II (HLA-II in humans). Petersen et al. report a 3.4-Å crystal structure of a human LAG-3–peptide–HLA-II complex. The LAG-3 homodimer binds two separate HLA-II molecules via its D1 domain, suggesting that LAG-3 binding is sensitive to ligand density and orientation on antigen-presenting cells. Moreover, LAG-3's binding site overlaps with the CD4–HLA-II binding site but is more extensive, explaining its higher affinity. —Seth Thomas Scanlon [ABSTRACT FROM AUTHOR]