Herbicide Mixtures Research Articles

Effect of Zinc Sulfate and Adjuvants on the Physicochemical Properties and Efficacy of Bromoxynil with Terbythylazine and Nicosulfuron Mixtures Against Echinochloa crus-galli L.

The study aimed to evaluate the effects of methyl esters adjuvant, pH reducer, and zinc sulfate on the physicochemical properties (contact angle, surface tension) of a spray liquid and a bromoxynil + terbuthylazine + nicosulfuron mixture’s efficacy. Cockspur (Echinochloa crus-galli L.) was used as the test plant. The placement of any adjuvant in the spray liquid affected the reduction in contact angle, with zinc sulfate reducing it from 75.9 to 66.3°, methyl esters adjuvant from 61.8 to 47.1°, pH reducer from 58.3 to 47.0°, zinc sulfate + methyl esters adjuvant from 64.9 to 58.4°, and zinc sulfate + pH reducer from 57.1 to 44.6°. A decrease in contact angle was found with a reduction in herbicide doses, from 65.6 to 59.0°. The highest pH of the spray liquid with herbicides was found when the methyl esters adjuvant was added to the liquid (6.82–7.17), followed by 6.43–6.80 when zinc sulfate was added, and 6.05–6.30 for zinc sulfate with methyl esters adjuvant. The inclusion of adjuvant pH reducer very strongly reduced the liquid reaction to 3.28–3.60, and it was reduced to 2.76–2.90 in the presence of zinc sulfate. Bromoxynil + terbuthylazine + nicosulfuron mixtures applied with methyl esters adjuvant and zinc sulfate with pH reducer showed the highest efficacy (85–98% and 82–96%), and the efficacy was 64–81% when methyl esters adjuvant with zinc sulfate were used. The effect of the herbicide mixture with only zinc sulfate was noticeably weaker (40–81%), and it was very weak (13–43%) in the presence of adjuvant pH reducer only. On the basis of the ED50 values, the most favorable mixtures were those containing methyl esters adjuvant, methyl esters adjuvant + zinc sulfate and pH reducer + zinc sulfate in addition to the herbicides. Research has indicated that zinc sulfate could be used as an adjuvant, and will support not only the action of herbicides, but also the development of maize plants.

Construction of a fusant bacterial strain simultaneously degrading atrazine and acetochlor and its application in soil bioremediation.

Application of herbicide-degrading bacteria is an effective strategy to remove herbicide in soil. However, the ability of bacteria to degrade a herbicide is often severely limited in the presence of other pesticide. In this study, the atrazine-degrading strain Klebsiella varicola FH-1 and acetochlor-degrading strain Bacillus Aryabhatti LY-4 were used as parent strains to construct the recombinant RH-92 strain through protoplast fusion technology. Compared with the parent strains, RH-92 exhibited enhanced ability to degrade herbicide mixture containing atrazine and acetochlor, exhibiting 63.16% and 68.48% higher degradation rates, respectively. RAPD analysis showed that gene rearrangement occurred during protoplast fusion, and the genetic similarity indexes of the fused strain RH-92 and the two parent strains were 0.5853 and 0.4240, respectively. HPLC-MS analysis confirmed that RH-92 shared similar degradation products and pathways with both parent strains but exhibited a novel metabolic pathway for the continuous degradation of CMEPA (degradation product of acetochlor) into MEA through amide bond hydrolysis. The activities of GSH, GST and SOD of RH-92 increased and the level of MDA decreased under the stress of compound herbicides. Strain RH-92 did not show a large number of bacterial apoptosis, and maintained good cell membrane integrity and permeability. The half-lives of atrazine and acetochlor were 4.9 d and 7.6 d when the parent strains FH-1 and LY-4 were applied in unsterilized soil containing herbicide mixture treatment,the application fusant RH-92 strain significantly reduced the half-life to 1.6 and 1.8 d, respectively. Furthermore, 16S rRNA sequencing indicated that RH-92 application effectively restored bacterial taxa with diminished relative abundances under herbicide mixture treatment, ameliorated phytotoxicity in soybean seedlings, and promoted enhanced vegetative growth in the roots and plant height. This study highlighted the application of fusant strains as a bioremediation strategy for combatting atrazine and acetochlor pollution in soil and provided theoretical insights.

Optimising aerial herbicide treatment for control of dense conifer infestations: a New Zealand case study.

Conifers, mainly of the genus Pinus, have invaded natural and productive landscapes worldwide. Controlling dense conifer invasions is challenging and requires both effective initial control methods and long-term site management to prevent re-invasion. Broadcast aerial herbicide application is often the preferred treatment method for dense infestations of pines with high rates of complex herbicide mixtures used. The objective of this study was to: (i) test the efficacy of four simple herbicide mixes (containing two active ingredients and one adjuvant) as compared to an operational standard (four active ingredients and three adjuvants) for control of Pinus contorta invasions in a field trial and (ii) to quantify the effect of treatment mixes on non-target vegetation to determine impacts to plant community composition. We found that a simplified herbicide mix containing two active ingredients and one adjuvant was equally as effective as the current operational standard, with efficacy for all treatments increasing as a function of stem density. All herbicide treatments significantly impacted the post-spray community composition with differences among treatments in post-spray vegetation composition also detected. Following all treatments plant communities transitioned from a mixed native/exotic grassland-herb community to a simplified community dominated by exotic grasses. Our results indicate a simpler herbicide mix could be used for broadcast aerial control of dense pine invasion reducing total herbicide input and cost of the operation. Post-spray vegetation community recovery could reflect the impact of the herbicides used in the operation compounded by soil biogeochemical processes already initiated through the pine invasion. © 2024 Society of Chemical Industry.

Sensitivity of difficult‐to‐control Palmer amaranth accessions to fluridone and diflufenican

AbstractPalmer amaranth (Amaranthus palmeri S. Watson) has evolved resistance to herbicides targeting nine sites of action. Phytoene desaturase‐inhibiting herbicides remain among the few sites of action that are still effective in controlling Palmer amaranth. Greenhouse experiments were conducted to evaluate the effectiveness of fluridone and diflufenican in controlling difficult‐to‐control Palmer amaranth accessions collected in Arkansas from 2016 to 2022, to quantify the response of three accessions that exhibited low sensitivity to both herbicides, and to evaluate the effectiveness of photosystem II inhibitors alone and with fluridone or diflufenican on three accessions. At 14 days after a preemergence application, Palmer amaranth control with fluridone and diflufenican ranged from 42% to 100% and 33% to 99% across 23 accessions, respectively. Three accessions required 10.2 to 26.7 times more fluridone than the susceptible Palmer amaranth standard based on LD50 values (where LD50 is the lethal dose to kill 50% of the population), with less than 50% mortality achieved with a 1x herbicide rate for two of the three accessions. For diflufenican, the LD50 values for the three accessions were 3.9–18.5 times greater than the susceptible standard. An additive response for mortality and biomass reduction resulted from adding fluometuron to fluridone at all rates tested. An additive or sometimes a synergistic response occurred with the combinations of metribuzin plus diflufenican. Overall, fluridone exhibited higher efficacy than diflufenican for most accessions tested. While phytoene desaturase‐inhibiting herbicides remain an effective control option for most Palmer amaranth accessions, herbicide mixtures targeting multiple sites of action remain essential for delaying resistance and obtaining effective control of this problematic weed.

Patterns of herbicide resistance in Raphanus raphanistrum revealed by comprehensive testing and statistical analysis.

Raphanus raphanistrum causes $40 million total revenue losses annually in Western Australia partly due to its historically-documented ability to evolve herbicide resistance to multiple modes of action. In this study, 376 field-sampled populations of R. raphanistrum were tested for resistance to 21 herbicides applied at the recommended label rate. Eight treatments were herbicide mixtures with two, three or four modes of action. A total of 7199 individual resistance tests were conducted across 4 years by screening approximately 104 000 individual seeds and seedlings. The mean survival of individuals within a population for all standalone herbicides was 9%, whereas survival was significantly decreased to 3.5% with a herbicide mixture. Some herbicides such as triasulfuron (herbicide Group 2), 2,4-D (Group 4) or diflufenican (Group 12) were highly impacted by resistance, with frequencies of resistant populations being > 50%. Conversely, there was negligible resistance to glyphosate (Group 9) or protoporphyrinogen oxidase (PPO) inhibitors (tiafenacil, saflufenacil + trifludimoxazin, fomesafen: Group 14), and pre-emergence herbicides (i.e., atrazine or mesotrione: Groups 5 and 27, respectively) remained largely effective. Binary, ternary or quaternary mixtures of Groups 4, 6, 12 and 27 herbicides reduced the frequency of high-level resistant populations to 7.1%, 3.8% or 0%, respectively. The cost-effective control of R. raphanistrum remains a challenge due to herbicide resistance. Raphanus raphanistrum management relies heavily on herbicide uses not yet compromised by resistance, such as pre-emergence herbicides (atrazine, fomesafen, mesotrione), glyphosate, and mixtures of two, three or four modes of action including bromoxynil, diflufenican, MCPA, picolinafen, pyrasulfotole and topramezone. Strategies that integrate effective herbicide use patterns, novel modes of action and efficiently-mechanized non-chemical weed control options (i.e., seed destructors) can completely constrain the selection of herbicide resistance in this highly adaptable species. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Efficacy of herbicide mixtures on weed density, weed dry biomass and weed control efficiency of transplanted finger millet (Eleusine coracana L. Gaertn)

Efficacy of herbicide mixtures on weed density, weed dry biomass and weed control efficiency of transplanted finger millet (Eleusine coracana L. Gaertn)

Toxicity of Post-Emergent Herbicides on Entomopathogenic Fungi Used in the Management of Corn Leafhopper: In Vitro and In Vivo Assessments

This is the first study to assess the physicochemical and biological compatibility of herbicides used in corn crops with entomopathogenic fungi used in the management of Dalbulus maidis in Brazil. The biological index was employed to ascertain the in vitro compatibility of the herbicides with pure spores (not formulated) of tested fungal isolates (Esalq-1296 of Cordyceps javanica and IBCB66 and Simbi BB15 of Beauveria bassiana). The results indicated a significant interaction between herbicides and fungal isolates when colony diameter and colony-forming units (CFU) were considered. Furthermore, changes in physicochemical characteristics were observed in some mixtures of herbicides and mycoinsecticides tested. The number of CFU was significantly reduced as the exposure time increased in the mixtures containing all the herbicides tested. In general, the Esalq-1296 isolate of C. javanica, formulated in a suspension concentrate (Octane®), proved to be more sensitive to the herbicides studied. In vivo bioassays demonstrated that, despite the synergistic effect of the binary mixtures of herbicides and mycoinsecticides on D. maidis mortality, the presence of the herbicide in the mixtures prevented the extrusion of entomopathogens from cadavers; therefore, caution is recommended when combining mycoinsecticides and post-emergent herbicides in tank mixtures aiming to manage D. maidis.

Herbicide resistance is complex: a global review of cross-resistance in weeds within herbicide groups

AbstractHerbicides have been placed in global Herbicide Resistance Action Committee (HRAC) herbicide groups based on their sites of action (e.g., acetolactate synthase–inhibiting herbicides are grouped in HRAC Group 2). A major driving force for this classification system is that growers have been encouraged to rotate or mix herbicides from different HRAC groups to delay the evolution of herbicide-resistant weeds, because in theory, all active ingredients within a herbicide group physiologically affect weeds similarly. Although herbicide resistance in weeds has been studied for decades, recent research on the biochemical and molecular basis for resistance has demonstrated that patterns of cross-resistance are usually quite complicated and much more complex than merely stating, for example, a certain weed population is Group 2-resistant. The objective of this review article is to highlight and describe the intricacies associated with the magnitude of herbicide resistance and cross-resistance patterns that have resulted from myriad target-site and non–target site resistance mechanisms in weeds, as well as environmental and application timing influences. Our hope is this review will provide opportunities for students, growers, agronomists, ag retailers, regulatory personnel, and research scientists to better understand and realize that herbicide resistance in weeds is far more complicated than previously considered when based solely on HRAC groups. Furthermore, a comprehensive understanding of cross-resistance patterns among weed species and populations may assist in managing herbicide-resistant biotypes in the short term by providing growers with previously unconsidered effective control options. This knowledge may also inform agrochemical company efforts aimed at developing new resistance-breaking chemistries and herbicide mixtures. However, in the long term, nonchemical management strategies, including cultural, mechanical, and biological weed management tactics, must also be implemented to prevent or delay increasingly problematic issues with weed resistance to current and future herbicides.

Improved management of Italian ryegrass (Lolium perenne spp. multiflorum) with mixtures of tiafenacil and ACCase or glutamine synthetase inhibitors

Abstract Herbicide-resistant Italian ryegrass [Lolium perenne L. spp. multiflorum (Lam.) Husnot] is a significant problem in multiple cropping systems because of its rapid growth, open pollination, prolific seed production, and multiple cases of resistance worldwide, except to protoporphyrinogen oxidase (PPO) inhibitors. This research evaluated tiafenacil, a new PPO inhibitor, in mixtures with glutamine synthetase or acetyl-CoA carboxylase (ACCase)-inhibiting herbicides to manage resistant L. multiflorum populations. Tiafenacil efficacy against L. multiflorum was growth stage-dependent, with increased efficacy at earlier stages in greenhouse studies. The LD90 was 41.06 g ai ha-1 at BBCH23, and increased to 9.0-fold at BBCH33. Field studies indicated that changes in carrier volume did not affect tiafenacil’s efficacy; the highest tested rate of tiafenacil (75 g ai ha-1) reduced L. multiflorum inflorescence weight by 50-90%. Mixtures of tiafenacil and glufosinate (1,150 g ai ha-1) improved L. multiflorum control (+24-43%) and reduced inflorescence weight (+15-34%), particularly at the highest tested rates (50 and 75 g ai ha-1), suggesting synergistic effects based on Colby’s test. Tiafenacil with ACCase inhibitors improved L. multiflorum control (+19-49%) and inflorescence weight reduction (+8-13%). These mixtures exhibited an additive effect when combined with fluazifop and a synergistic effect with clethodim. Herbicide mixtures and application strategies are critical to effective L. multiflorum management. Tiafenacil, especially when used with glufosinate or ACCase inhibitors, offers an effective solution to L. multiflorum management and is a strategic tool against herbicide resistance, as resistance to PPO inhibitors has not evolved. Further research should assess practices to ensure the long-term viability of these mixtures for resistance management.

Efficacy of new generation herbicide mixtures in irrigated maize (Zea mays)

The experiment was conducted during rainy (kharif) seasons of 2020 and 2021 at Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu to study the efficacy of new generation herbicide mixtures in irrigated maize (Zea mays L.). The experiment was laid out in a randomized complete block design (RCBD) consisted of 9 treatments including pre-emergence herbicides, new generation post emergence herbicides and other weed management practices [T1, Weedy check; T2, Weed free check; T3, Spraying of atrazine @1 kg/ha as pre-emergence + Hand weeding on 25 DAS (days after sowing); T4, Spraying of atrazine @0.75 kg/ha as pre-emergence + Spraying of topramezone @25.2 g/ha as post-emergence on 25 DAS; T5, Spraying of atrazine @0.75 kg/ha as pre emergence + Tembotrione @120 g/ha on 25 DAS; T6, Spraying of atrazine @1 kg/ha as pre-emergence + Topramezone @25.2 g/ha on 25 DAS; T7, Spraying of atrazine @1 kg/ha as pre-emergence + Tembotrione @120 g/ha on 25 DAS; T8, Spraying of topramezone @25.2 g/ha + atrazine @0.75 kg/ha on 15 DAS; and T9, Spraying of tembotrione @120 g/ha + atrazine @0.75 kg/ ha on 15 DAS], replicated thrice. The results evinced that application of topramezone at 25.2 g/ha + atrazine at 0.75 kg/ha on 15th day after sowing significantly reduced the weed density and dry weight leading to higher weed control efficiency and lower weed index of 62.0% and 3.1%, respectively, during both the years of study. This treatment resulted in higher grain yield (7675 kg/ha), net returns (₹72884/ha) and benefit cost (B:C) ratio (2.33) in irrigated maize.

Effect of Nano-Urea Based Nitrogen Management and Herbicide Mixtures on Rhizospheric Dynamics of Wheat for Enhanced Productivity, Profitability and Yield Emission Trade-Offs

Effect of Nano-Urea Based Nitrogen Management and Herbicide Mixtures on Rhizospheric Dynamics of Wheat for Enhanced Productivity, Profitability and Yield Emission Trade-Offs

Long-Term Herbicide Mixture Exposure Increases Hypertension Risk and Aging Biomarkers Play Mediation Effects: A Nested Case-Control Study

Long-Term Herbicide Mixture Exposure Increases Hypertension Risk and Aging Biomarkers Play Mediation Effects: A Nested Case-Control Study

Synergistic effect of pyridate-based herbicide mixtures for controlling multiple herbicide-resistant kochia

Abstract Multiple herbicide classes resistant (MHCR) kochia poses a serious concern for producers in the Central Great Plains, including western Kansas. Greenhouse and field experiments were conducted at Kansas State University Research and Extension Centers near Hays and Garden City, KS to evaluate pyridate-based postemergence (POST) herbicide mixtures for controlling MHCR kochia. One previously confirmed MHCR population (resistant to atrazine, glyphosate, dicamba, and fluroxypyr) and a susceptible (SUS) kochia population were tested in a greenhouse study. The kochia population at Hays field site was resistant to atrazine, dicamba, and glyphosate while kochia population at Garden City site was resistant to atrazine and glyphosate. Colby’s analysis revealed synergistic interactions when pyridate was mixed with atrazine, dicamba, dichlorprop-p, fluroxypyr, glyphosate, or halauxifen/fluroxypyr and resulted in ≥94% control and shoot dry biomass reduction of MHCR kochia in a greenhouse study. Similarly, synergistic interactions were observed for MHCR kochia control in fallow field studies at both sites when pyridate was mixed with glyphosate or atrazine. Kochia control was increased from 26% to 90% with the application of glyphosate + pyridate and from 28% to 95% with atrazine + pyridate at both sites as compared to separate applications of glyphosate or atrazine. This is the first report for such a strong synergistic effect for both glyphosate and atrazine mixtures with pyridate on a weed resistant to both. All other pyridate-based herbicide mixtures showed an additive interaction and resulted in better control of MHCR kochia (87 to 100%) as compared to their individual applications (23 to 92%) across both sites except 2,4-D. These results suggest that pyridate can play a crucial role in various POST herbicide mixtures for effective control of MHCR kochia.

Impacts of herbicides used for control of invasive Pinus contorta on the potential for reinvasion and germination of restoration species

AbstractHerbicides that persist in the forest litter and soil following their use for managing invasive plant species may negatively affect restoration efforts as well as minimize reinvasion via their residual phytotoxic activity. This study determined the impact of an herbicide mixture comprising triclopyr, dicamba, picloram, and aminopyralid (TDPA) for the control of dense infestations of a woody invader, Pinus contorta Douglas ex Loudon, on the germination of reinvading P. contorta and three New Zealand native species (Chionochloa rubra Zotov, Nothofagus cliffortiodes (Hook. f.) Oerst., and Leptospermum scoparium J.R. Forst. & G. Forst.) used in restoration. Given the essential role of ectomycorrhizal fungi in facilitating conifer reinvasion, the impact of residual herbicides present in mineral soil on the ectomycorrhizal infection of P. contorta seedling roots was also examined. Germination trials were conducted using intact forest litter–soil cores collected at 27, 112 and 480 d (after herbicide spraying) from sprayed and adjacent unsprayed dense P. contorta infestations. At the same time, mineral soil was also collected for the ectomycorrhizal infection study. Post-spray herbicide residue bound in the litter significantly decreased survival, germination rate, root and shoot growth, and also caused malformation of P. contorta seedlings. Similar results were recorded for native species’ germination; however, overall viability of native seed was poor, resulting in low germination rates. There was no difference in levels of ectomycorrhizal infection rates of P. contorta between treatments. Results indicate residual levels of TDPA herbicide in forest floor litter negatively affect P. contorta reinvasion, native recruitment, and active restoration management. Ectomycorrhizal fungi, however, are unaffected by this herbicide mixture and therefore remain a risk to facilitating reinvasion as residual herbicide declines.

Systems of basic tillage and weed infestation of the spring barley crops

In the course of research the influence of duration of exposure to different tillage systems on the weed infestation of crops and yield of spring barley was determined. Stationary field experiments were carried out in the Scientific Research Institute of Agriculture for Northern Trans-Ural Region – Branch of Federal State Institutions Federal Research Centre Tyumen Scientific Centre of Siberian Branch of the Russian Academy of Sciences – in the northern forest-steppe of the Tyumen Oblast. Observations (2018-2022) were carried out in the 7th rotation of grain-fallow crop rotation: complete fallow – winter rye – spring wheat – spring wheat – spring barley. The following systems of basic tillage were compared: moldboard, nonmoldboard, combined, differentiated, sweep and shallow systems. The soil of the experimental plot is dark gray forest soil, heavy loamy, typical for the zone by its characteristics. A mixture of preparations against dicotyledonous and cereal weeds was applied as a general background. Prolonged (during 35 years) application of basic tillage systems of different intensities in cereal crops in grain and fallow crop rotation using a mixture of herbicides against mixed type of weeding contributed to the formation of low and medium degree of weed infestation, mainly annual small-seeded weeds. At the same time, the indicator of total damage (the mass of weeds is 1.13–4.47 % of the biomass of cultivated plants) was low. The moldboard system of basic tillage proved to be the most effective in combating weeds. The highest weed infestation was observed in the nonmoldboard system (243.3 pcs./m2): in spring – 1.8 times more by number, in autumn - 4 times more by weight in comparison with the moldboard tillage system. When cultivating cereals in crop rotation with the use of complex chemicalization means, the possibility of using resource-saving tillage systems is justified by maintaining a low level of weed infestation and its harmfulness, the absence of negative impact on yield.

Herbicide Combinations for Effective Weed Management in Rice

Rice (Oryza sativa L.) is the most important food crop catering half of the world’s population. India being the second largest producer of rice, needs to produce around 120 million tons of rice by 2030 to feed its one and a half billion plus population. Weeds are undoubtedly a major biotic constraint to rice production in most of the rice growing areas of the world. Rice fields are very often characterized by a complex plurispecific weed flora, comprising of grasses, sedges, and broad-leaved weeds (BLWs). They usually grow faster than rice and absorb available water and nutrient earlier than the rice and suppress rice growth. Cultural and mechanical methods of weed management in general, are time consuming, cumbersome and laborious apart from being less effective because of chance of escape and regeneration of weeds from roots or rhizome that are left behind. Herbicides offer the most effective, economical and practical way of weed management. Since rice ecosystems usually harbours a variety of weeds, the use of a single herbicide cannot give satisfactory results. Moreover, continous use of such herbicides leads to the evolution of weeds resistant to several herbicides. Therefore, more convenient option would be single shot application of ready mix or tank mix combination of herbicide. The herbicide mixtures broaden the spectrum of weed control in single application. The ideal herbicide combinations are those that effectively target the weed species while minimizing toxicity to crops, thereby exhibiting enhanced selectivity. Using herbicide combinations allows for reduced herbicide use rates compared to using a single herbicide. Additionally, apart from providing broad-spectrum weed control, herbicide combinations reduce the herbicide load in the environment and minimize application costs. Among the various combination herbicides available, the ones having pre-emergence and post-emergence herbicides combined had shown better weed control with single shot application at reduced cost. Some of the ready-mix herbicide combinations that are gaining greater importance includes Pretilachlor + Pyrazosulfuron-ethyl, Pendimethalin + Penoxsulam and Butachlor + Penoxsulam.

MAIN TECHNOLOGICAL MEASURES IN THE GROWING OF CHEEPA IN THE CONDITIONS OF THE FOREST STEPPE OF THE RIGHT BANK

Weed counts on chickpea crops revealed a mixed type of weed infestation. The most common among dicotyledons are white quinoa, rough mustard, common bindweed, small-flowered galigsoga, odorless chamomile, field bindweed, and pink thistle; among cereals: blue marestail, common bentgrass, and creeping wheatgrass. The chemical method dominates in the system of protective measures for chickpea cultivation. The use of herbicides during the most vulnerable periods of weed growth, namely during seed germination, creates the most favorable conditions for the growth and development of chickpea plants by eliminating competition for light, moisture, nutrients, etc. To reduce the phytotoxic (negative) effects of herbicides on chickpea plants, tank mixtures of herbicides should be used in reduced doses, chickpea seeds should be inoculated, and biological products with immunomodulatory properties and stimulating activity should be used during the growing season. The application of Harness herbicide, 90% c.e., at a rate of 3.0 l/ha before chickpea germination leads to a decrease in weed vegetation one month after the application of the herbicide to 86% compared to the control plots. This preparation effectively destroyed annual cereal weeds by 94% compared to the control plots and was less effective against annual dicotyledonous weeds, up to 77% compared to the control. On the plots where Frontier Optima herbicide was applied, 72% e.c. at a rate of 1.2 l/ha, the number of weeds was within 20 pcs/m2 a month after application, and the level of weediness decreased by 88% compared to the control plots (natural weediness). This herbicide effectively killed cereal weeds and was selective to dicotyledonous weeds. At the time of chickpea harvesting, the number of weeds was within 27 pcs/m2, and the level of weediness decreased by 84% compared to the control plots. With the complex use of herbicides Harness and Frontier Optima in reduced consumption rates, a better effect on weed control in chickpea crops was noted. The level of weed infestation during the chickpea harvesting period decreased by 88% compared to the control plots. It should be noted that this composition of soil herbicides had reduced application rates and was characterized by prolonged action against weeds. The highest yields of chickpea seeds were in the variant where inoculation with Rhizobophyte was carried out at a rate of 1.0 l/t before sowing chickpea, a tank mixture of herbicide Harness + Frontier Optima was applied at application rates of 2.5-1.0 l/ha, and in the phase of 3-4 leaves, foliar application of the biological preparation Agrinos B was carried out. As a result of the measures taken, the yield of chickpea seeds averaged 2.44 t/ha over the years of research, which is 2.07 t/ha more than in the control plots.

Evaluation of crop estiblishment techniques and herbicide mixtures for enhancing the productivity of Rice fallow blackgram (Vigna mungo L.)

Evaluation of crop estiblishment techniques and herbicide mixtures for enhancing the productivity of Rice fallow blackgram (Vigna mungo L.)

Adsorption behavior of solids incorporated in alginate hydrogel beads using herbicides 2,4-D and paraquat as test molecules

This study investigates the behavior of adsorbent solids within three-dimensional networks of biopolymers. Two chemically different herbicides, 2,4-D and paraquat (PQ) were employed as test molecules. Alginate (ALG) hydrogels in bead form were synthesized, incorporating activated carbon (PSCA) and montmorillonite clay (MMT) simultaneously and in varying proportions, resulting in multicomponent beads. The Langmuir isotherm parameters, KL (L mmol−1) and qmax (mmol g−1), in the adsorption of herbicides on beads with an increasing amount of montmorillonite (MMT) were as follows: For PQ, KL values were 10.709, 61.951, 162.33, 223.27, and qmax values were 0.0711, 0.1484, 0.2135, 0.2497. For 2,4-D, KL values were 13.360, 8.3234, 7.4126, 5.4308, and qmax values were 0.9529, 0.7096, 0.6534, 0.5881. The values clearly demonstrates that, even when solids are mixed in the hydrogel network, their reactive sites remain exposed, interacting with molecules to which they have greater affinity. Adsorption was also investigated on identical materials using binary mixtures of herbicides, revealing trends similar to those observed for individual solutions. Moreover, it was demonstrated that the adsorption capacity of multicomponent beads is equivalent to that achieved by proportionally mixing beads synthesized exclusively with clay or activated carbon. This suggests the tangible possibility of creating on-demand adsorbents by synthesizing distinct hydrogels, each incorporating a specific solid. Subsequently, drying, storing, and mixing them based on the target contaminant for retention are feasible. Finally, a column was packed with a proportional mixture of beads and successfully retained PQ and 2,4-D using a flow-through system.

Integrated effects of crop rotation and different herbicide rates in maize (Zea mays L.) production in central Serbia

Successful maize (Zea mays L.) cultivation is largely reliable by weed interference. Among weeds, annual species are usually dominant, whereas less prevalent perennials can be challenging to control, too. Driven by profitability, maize is often cultivated continuously using the same management practices over time, resulting in increased weed infestations, particularly perennials. However, crop rotation might reduce the abundance of weed species, lower herbicide impact on the environment, delaying herbicide resistance occurrence in weeds and thus contribute to sustainable maize production,. The aim of this study was to explore the impact of continuous maize cropping (Maize-CC) and a three-crop rotation, maize–winter wheat–soybean (Maize-WW-S), in combination with three weed management treatments: 1) application of a pre-emergence herbicide mixture of acetochlor/S-metolachlor + isoxaflutole at the full label rate, 2) at ½ of full label rate, and 3) an the untreated control, over a 12-year period. The trial was initiated in 2009, and maize was grown in both cropping systems, Maize-CC and Maize-WW-S, in 2012, 2015, 2018, and in 2021. Total weed density, fresh biomass of all annual and perennial weed species and total dry biomass of all weed species was measured four weeks after herbicide application. Maize leaf area index (LAI) was measured at the anthesis, whereas grain yield was measured at the end of the growing cycle. Weed species diversity, number of individuals, weed fresh and dry biomass, were significantly lower with the combination of Maize-WW-S and the herbicide treatments. Grain yield was significantly and negatively correlated with the fresh weight of annual weeds in Maize-CC and was higher in both herbicide treatments, especially in Maize-WW-S. There was no significant difference between pre-emergence herbicide full labelled rate and ½ of the labelled rate in reducing the total fresh weed biomass in Maize-CC (66.3% and 65.9%, respectively) and Maize-WW-S (92.1% and 85.8%, respectively). Thus, the importance of the combined employment of rotation and chemical measures in maize production was confirmed and could be adopted for long-term weed management without compromising yields.