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1
Milosevic, Nada y Mitar Govedarica. "Effect of herbicides on microbiological properties of soil". Zbornik Matice srpske za prirodne nauke, n.º 102 (2002): 5–21. http://dx.doi.org/10.2298/zmspn0201005m.
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Microorganisms decompose herbicides and they may serve as bioindicators of soil changes following herbicide application. Certain microbial species may be used as bioherbicides. This study has shown that Azotobacter is most sensitive to herbicide application; it is, therefore, a reliable indicator of the biological value of soil. The numbers of this group of nitrogen-fixing bacteria decrease considerably in the period of 7-14 days after herbicide application. Simultaneously, the numbers of Actinomycetes and less so of fungi increase, indicating that these microorganisms use herbicides as sources of biogenous elements. Rate of herbicidal decomposition depends on the properties of the preparation applied herbicide dose as well as on the physical and chemical soil properties, soil moisture and temperature, ground cover, agrotechnical measures applied and the resident microbial population.
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Redlick, Collen, Hema S. N. Duddu, Lena D. Syrovy, Christian J. Willenborg, Eric N. Johnson y Steven J. Shirtliffe. "Effect of Seeding Rate on Dose Response of Wild Mustard (Sinapis arvensis) to Fluthiacet-Methyl". Weed Science 65, n.º 4 (9 de junio de 2017): 525–33. http://dx.doi.org/10.1017/wsc.2017.9.
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Concern over the development of herbicide-resistant weeds has led to interest in integrated weed management systems that reduce selection pressure by utilizing mechanical and cultural weed control practices in addition to herbicides. Increasing crop seeding rate increases crop competitive ability and thus can enhance herbicide efficacy. However, it is unknown how increasing the seeding rate affects an herbicide’s efficacy. The objective of this study was to examine the interaction between increasing seeding rate and herbicide dose to control weeds. To meet this objective, the herbicide fluthiacet-methyl was applied to field-grown lentil, with Indian mustard, a proxy for wild mustard, used as a model weed. The experiment was a factorial design with four lentil seeding rates and seven herbicide rates. Overall the herbicide dose response was altered by changing lentil seeding rate. Increasing lentil seeding rate decreased the weed biomass production when herbicides were not applied. In two of the four site-years, increasing lentil seeding rate lowered the herbicide ED50, the dose required to result in a 50% reduction in weed biomass. Increasing the crop seeding rate altered the dose response to provide greater weed control at lower herbicide rates compared with normal crop seeding rates. Increased seeding rates also resulted in higher and more stable crop seed yields across a wider range of herbicide dosages. These results suggest that dose–response models can be used to evaluate the efficacy of other weed management practices that can interact with herbicide performance.
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Lobachev, Yuriy Viktorovich y Valeriy Tikonovich Krasilnikov. "The effect of new tank mixtures and herbicide compositions on economically useful indicators of soy". Agrarian Scientific Journal, n.º 2 (19 de febrero de 2020): 16–23. http://dx.doi.org/10.28983/asj.y2020i2pp16-23.
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The method of two-way analysis of variance in three field experiments in the conditions of the Right Bank of the Saratov Region studied the effect of four herbicides, two new tank mixtures and two new herbicide compositions on grain yield, number of plants per square meter, number of beans per plant, number of grains per plant, plant mass, the mass of beans from the plant, the mass of grain from the plant, the mass of 1000 grains, the protein content in the grain, the height of the plant, the height of attachment of the lower bean. The effectiveness of the herbicides was as follows: frontier optima - 72.5%, pulsar - 26.5%, gezagard - 71.2%, galaxy top - 11.7%, tank mixture frontier optima + gezagard - 86.4%, tank mixture pulsar + galaxy top - 23.0%, composition frontier optima + galaxy top - 73.8%, and composition gezagard + galaxy top - 85.1%. It was established a significant advantage in grain yield of only one new tank mixture of herbicides frontier optima + gezagard and two new compositions of herbicides frontier optima + galaxy top and gezagard + galaxy top. In the case of application of a tank mixture of herbicides, the frontier optima + hezagard yields of soybean grain significantly increased compared with the control by 377.0%, compared with herbicides the frontier optima and hezagard - by 154.0%. After the application of the herbicidal composition, the frontier optima + galaxi top soybean grain yield significantly increased compared with the control by 293.3%, compared with the herbicide frontier optima - by 120.1%, compared with the herbicide galaxy top - by 139.3%. After application of the hezagard + galaxy top herbicide composition, the soybean grain yield significantly increased compared with the control by 294.3%, compared with the hezagard herbicide - by 121.7%, compared with the galaxy top herbicide - by 141.1%.
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Wang, Pei, Hui Li, Weidong Jia, Yin Chen y Roland Gerhards. "A Fluorescence Sensor Capable of Real-Time Herbicide Effect Monitoring in Greenhouses and the Field". Sensors 18, n.º 11 (5 de noviembre de 2018): 3771. http://dx.doi.org/10.3390/s18113771.
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Herbicide resistant weeds need to be identified early so that yield loss can be avoided by applying proper field management strategies. A novel chlorophyll-fluorescence-imaging sensor has been developed to conduct real-time herbicide effect evaluation. In this research, greenhouse and field experiments were conducted to calibrate the capability of the sensor in monitoring herbicide effects on different biotypes of two grass weeds (Alopecurus myosuroides, Apera spica-venti) in southwestern Germany. Herbicides with different modes of action were applied for the effect monitoring. Chlorophyll fluorescence yield of the plants was measured 3–15 days after treatment (DAT) using the new fluorescence sensor. Visual assessment of the weeds was carried out on 21 DAT. The results showed that the maximal PS II quantum yield (Fv/Fm) of herbicide sensitive weeds was significantly lower than the values of resistant populations in 5 DAT. The new technology was capable of quickly identifying the herbicide’s effect on plants. It can be used to optimize management strategies to control herbicide resistant weeds.
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Samadi Kalkhoran, Elham, Mohammad Taghi Alebrahim, Hamid Reza Mohammaddoust Chamn Abad, Jens Carl Streibig, Akbar Ghavidel y Te-Ming Paul Tseng. "The Survival Response of Earthworm (Eisenia fetida L.) to Individual and Binary Mixtures of Herbicides". Toxics 10, n.º 6 (12 de junio de 2022): 320. http://dx.doi.org/10.3390/toxics10060320.
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Frequent use of herbicides may impose a risk on non-target species. The objective was to test the combined toxic effect of binary herbicide mixtures—metribuzin:halosulfuron and metribuzin:flumioxazin—on non-target earthworms in two test systems: filter paper and a soil toxicity test system. The joint action experiments were independently run twice to substantiate the findings. The most potent individual herbicide was metribuzin, with a 50% lethal concentration (LC50) of 17.17 µg ai. cm−2 at 48 h in the filter paper test. The toxicity of the individual herbicides on the filter paper test was ranked as metribuzin>halosulfuron>flumioxazin. In the soil test, metribuzin and halosulfuron had high toxicity with an LC50 of 8.48 and 10.08 mg ai. kg−1, respectively, on day 14. Thus, the individual herbicide ranking did not change between the filter paper and artificial soil tests. The herbicide’s mixed effect in both test systems showed a consistent antagonistic effect relative to a Concentration Addition reference model. It indicates that the mixtures retracted the herbicide’s action in the earthworms.
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Gao, Liu, Jiang, Fu, Zhao, Li y Ye. "Protective Responses Induced by Chiral 3-Dichloroacetyl Oxazolidine Safeners in Maize (Zea mays L.) and the Detoxification Mechanism". Molecules 24, n.º 17 (22 de agosto de 2019): 3060. http://dx.doi.org/10.3390/molecules24173060.
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Herbicide safeners selectively protect crops from herbicide injury while maintaining the herbicidal effect on the target weed. To some extent, the detoxification of herbicides is related to the effect of herbicide safeners on the level and activity of herbicide target enzymes. In this work, the expression of the detoxifying enzyme glutathione S-transferase (GST) and antioxidant enzyme activities in maize seedlings were studied in the presence of three potential herbicide safeners: 3-dichloroacetyl oxazolidine and its two optical isomers. Further, the protective effect of chiral herbicide safeners on detoxifying chlorsulfuron in maize was evaluated. All safeners increased the expression levels of herbicide detoxifying enzymes, including GST, catalase (CAT), and peroxidase (POD) to reduce sulfonylurea herbicide phytotoxicity in maize seedlings. Our results indicate that the R-isomer of 3-(dichloroacetyl)-2,2,5-trimethyl-1,3-oxazolidine can induce glutathione (GSH) production, GST activity, and the ability of GST to react with the substrate 1-chloro-2,4-dinitrobenzene (CDNB) in maize, meaning that the R-isomer can protect maize from damage by chlorsulfuron. Information about antioxidative enzyme activity was obtained to determine the role of chiral safeners in overcoming the oxidative stress in maize attributed to herbicides. The interaction of safeners and active target sites of acetolactate synthase (ALS) was demonstrated by molecular docking modeling, which indicated that both isomers could form a good interaction with ALS. Our findings suggest that the detoxification mechanism of chiral safeners might involve the induction of the activity of herbicide detoxifying enzymes as well as the completion of the target active site between the safener and chlorsulfuron.
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Zarzecka, Krystyna, Marek Gugała, Iwona Mystkowska y Anna Sikorska. "Changes in dry weight and starch content in potato under the effect of herbicides and biostimulants". Plant, Soil and Environment 67, No. 4 (30 de marzo de 2021): 202–7. http://dx.doi.org/10.17221/622/2020-pse.
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The aim of the study was to determine the interaction of herbicides and herbicides with biostimulants on the accumulation of dry matter and starch in potato tubers. In a three-year field experiment based on the method of randomised sub-blocks, two factors were taken into account. The first factor were potato cultivars: Bartek, Gawin, Honorata. The second factor were five methods of herbicides and biostimulants application: (1) the control object without chemical protection (CO); (2) herbicide linuron + clomazone (Harrier 295 ZC) (H); (3) herbicide linuron + clomazone (Harrier 295 ZC) and biostimulant Ecklonia maxima (Kelpak SL) – (H + K); (4) herbicide metribuzin (Sencor 70 WG) – (S); (5) herbicide metribuzin (Sencor 70 WG) and biostimulant sodium para-nitrophenol, sodium ortho-nitrophenol, sodium 5-nitroguaiacol (Asahi SL) – (S + A). The cultivars and weather conditions significantly affected the content and yields of dry matter and starch. The herbicides and biostimulants used determined the starch accumulation as well as dry matter and starch yields. Most starch in tubers (more by 3.7 g/kg) and the highest dry matter and starch yields (more by 2.87 and 1.79 t/ha, respectively), compared to the control object, were obtained after the application of the herbicide Sencor 70 WG and biostimulant Asahi SL.
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Petrova, Sofia, Stanislav Stamatov y Blagoy Andonov. "Study of the effect of different herbicides and herbicidal combinations on weed flora and chickpea yield". Agricultural Sciences 14, n.º 32 (18 de marzo de 2022): 31–36. http://dx.doi.org/10.22620/agrisci.2022.32.005.
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Chickpea (Cicer arietinum L.) is the third most important grain legume crop in the world and the first important legume in the South and West Asia. For Bulgaria the chickpea is an old traditional crop used mainly for human consumption and to a lesser extent for feed. One of the most important yield limiting factors in the chickpea seed production is the poor weed management. The establishment of the most appropriate herbicide or herbicide combination for the effective control especially of the weed flora is a priority task of the chickpea cultivation. The aim of this study was to investigate the effect of different herbicides and herbicidal combinations on weed flora and on the chickpea yield. The herbicides and herbicidal combinations were tested in nine treatments plus one weedy check control. All herbicides were used in pre-emergence applications at different doses. During the study the predominated weeds were Amaranthus retroflexus L. (redroot pigweed) and Convolvulus arvensis L. (field bindweed). Generally, all tested herbicidal combinations showed good control on the mixed weed flora and the grain yield was high. Three herbicidal combinations had the best effect on weed numbers and grain yield compared to the weed check: Clomazone -15 ml/da + S-metolachlor - 120 ml/da; Clomazone - 30 ml/da + S-metolachlor - 60 ml/da and Clomazone - 15 ml/da + Pendimethalin - 500 ml/da. Most of the studied herbicides and herbicidal combinations were tolerant, non-suppressive and showed a high positive effect on the chickpea yield.
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Swanson, Bert T. y James B. Calkins. "Weed Control Strategies for Field- and Container-grown Herbaceous Perennials". HortScience 30, n.º 4 (julio de 1995): 894E—894. http://dx.doi.org/10.21273/hortsci.30.4.894e.
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Fourteen herbicides or herbicide combinations, a wood chip mulch, a chipped rubber tire mulch, and a newspaper mulch were evaluated for weed control efficacy and potential phytotoxicity using 12 species of herbaceous perennials under field-growing conditions. Nineteen herbicides or herbicide combinations were similarly evaluated under container-growing conditions using 11 species of herbaceous perennials. The effect of herbicide application time also was monitored through application of herbicides to dormant and actively growing plants. Herbicides and mulch treatments were compared to weeded and nonweeded controls. Herbicide phytotoxicity effects were dependent on the age and species of the herbaceous perennial and herbicide application timing. Herbicide injury was generally greater for newly established plants compared to established plants. Although injury was usually reduced when herbicides were applied to dormant plants, injury was sometimes greater when herbicides were applied in early spring compared to applications made in late spring after complete herbaceous perennial emergence. This effect resulted in injury to young shoots that had emerged before the earliest possible time that herbicides could be applied in early spring. A wood chip mulch provided the most effective weed control and highest quality plants under field growing conditions. Several of the herbicides evaluated demonstrated potential for weed control in both field and container herbaceous perennial production systems and landscape plantings.
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Beckie, Hugh J., Fa-Yan Chang y F. Craig Stevenson. "The Effect of Labeling Herbicides with Their Site of Action: A Canadian Perspective". Weed Technology 13, n.º 3 (septiembre de 1999): 655–61. http://dx.doi.org/10.1017/s0890037x00046364.
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Industry, public-sector researchers and extension agents, and growers were surveyed in 1998 to determine their perspectives on how labeling herbicides with their site of action (group number) would affect the herbicide use practices of growers. The crop protection industry in Canada represented by the Crop Protection Institute (CPI) generally supports herbicide resistance labeling but has some concerns regarding the wording of the labels, including the identification symbol. Most researchers and extension agents believe that labeling herbicides with their site of action will facilitate herbicide group rotation by growers who frequently use herbicides from the same group. Of the two-thirds of the 126 surveyed growers who were familiar with herbicide groupings, 58% practiced herbicide group rotation. Those who did not tended to lack understanding of the basis and purpose of herbicide classification. Grower responses were similar to those from the research and extension community, although only 29% of the growers who currently do not rotate herbicides from different groups believed that resistance management labeling would influence them.
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Dear, BS, GA Sandral y NE Coombes. "Change in stomatal resistance and water use in subterranean clover (Trifolium subterraneum L.) in response to broadleaf herbicides". Australian Journal of Agricultural Research 47, n.º 4 (1996): 625. http://dx.doi.org/10.1071/ar9960625.
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The effect of 5 broadleaf herbicides on the water use and stomatal resistance of 2 cultivars of subterranean clover (Trifolium subterraneum L.) was examined in a glasshouse study. The herbicide treatments 2,4-DB, MCPA, bromoxynil, MCPA+terbutryn, and MCPA+diuron were applied at 6 rates at 2 times (14 May, 14 June) to plants at 2 leaf stages (3-4 and 8-10 leaves). Each of the herbicides reduced water use by the clover within 24 h, the size of the reduction increasing with the rate of herbicide applied. The herbicide treatments MCPA+terbutryn, MCPA+diuron, and bromoxynil caused the largest reductions (44-52%) in total water use over the 30-day period when applied at the recommended rate, and MCPA and 2,4-DB the least reduction (16-22%). Stomatal resistance increased substantially within 2 days of application of each of the herbicides. The magnitude of the change differed with herbicide and increased with herbicide rate. The effect of the herbicides on stomatal resistance declined 10-20 days after herbicide application in all treatments except 2,4-DB, but stomatal resistance of all herbicide-treated plants was still higher than the control 30 days after herbicide application. The herbicides LICPA+terbutryn and LlCPA+diuron and bromoxynil caused the largest increase in stomatal resistance and 2,4-DB the least. Stomatal resistance was found to be highly negatively correlated with daily water use by the clover plants at 2 days (r = -0.84, P < 0.01) and 30 days (r = -0.88, P < 0.01) after herbicide application. All of the herbicides reduced the LA1 of the plants, the effect increasing as the herbicide rate increased. Herbicide and herbicide rate had the largest effect on both water use and stomatal resistance; the effect of cultivar, leaf stage, and spraying time accounted for a relatively small proportion of the variance. The findings support the hypothesis that some broadleaf herbicides can result in a water-saving effect in subterranean clover swards through increasing stomatal resistance and decreasing the LAI, thereby potentially reducing moisture stress during seed set.
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Parshad, Jagdish, Dharam Bir Yadav, Satbir Singh Punia, Kuldeep Singh y Baljeet Singh. "Assessment of soil micro flora in rice-wheat cropping system through continuous and rotational herbicide applications". INTERNATIONAL JOURNAL OF AGRICULTURAL SCIENCES 17, n.º 2 (15 de junio de 2021): 455–61. http://dx.doi.org/10.15740/has/ijas/17.2/455-461.
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A long term experiment was conducted at CCS Haryana Agricultural University, Regional Research Station, Uchani (Karnal), India. Assessment of fix and rotational herbicides with and without green manure on the microbial population were studied in wheat crop during 2017-18. The treatments included fix/continuous herbicide (Clodinafop) and rotational herbicide (Sulfosulfuron) to control weeds along with weed free and weedy checks. Rhizosphere samples of wheat were collected from different plots of fixed and rotational herbicides treated soil to assess the total bacterial count, phosphate solubilizing microorganisms, actinobacteria, fungi and free-living diazotrophs. Weed free and weedy check served as check (control) for total microbial populations in the soil. Initially, herbicidal application showed negative effect on the soil microbes but retain the number later on as compared to weedy check under both conditions. But the effects of the herbicides on the micro flora in soil could be nullified through green manure.
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Timergalin, Maxim D., Arina V. Feoktistova, Timur V. Rameev, Gaisar G. Khudaygulov, Sergei N. Starikov y Sergei P. Chetverikov. "Agroecological aspects of application of Pseudomonas sp. DA1.2 in overcoming herbicidal stress in wheat". BIO Web of Conferences 23 (2020): 03009. http://dx.doi.org/10.1051/bioconf/20202303009.
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This article submits results of laboratory and field experiments on the effect of an auxin-producing bacterial strain Pseudomonas sp. DA1.2 in comparison with Pseudomonas koreensis IB-4 on wheat plants in conjunction with the “Chistalan” herbicide treatment. Our work shows the positive effect of bacterial treatments on plant growth, the relative water content in leaves and the role of bacteria in the redistribution of ABA and IAA in wheat shoots under conditions of herbicidal stress. Application of Pseudomonas sp. DA1.2 together with the herbicide in the field of the steppe zone led to an increase in yield by 20% relative to the control variant. This bacterial strain helps to overcome herbicidal stress and is a promising agent for improving the technology of using synthetic auxins herbicides.
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Peek, Daniel C. y Arnold P. Appleby. "Effect of pH on Phytotoxicity of Metribuzin and Ethyl-metribuzin". Weed Technology 3, n.º 4 (diciembre de 1989): 636–39. http://dx.doi.org/10.1017/s0890037x00032942.
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The influence of pH on the behavior of metribuzin and ethyl-metribuzin in soil and nutrient solution was studied. Toxicity of both herbicides to oats decreased as soil pH decreased from 8.4 to 4.2 in a sandy loam. Herbicide adsorption increased as soil pH decreased. In nutrient solution, pH did not change the phytotoxicity of either herbicide, indicating that pH primarily influences herbicide availability in soil and not plant uptake.
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Harrison, Howard F. "Developing Herbicide-Tolerant Crop Cultivars: Introduction". Weed Technology 6, n.º 3 (septiembre de 1992): 613–14. http://dx.doi.org/10.1017/s0890037x00035909.
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In recent years considerable research in the private and public sectors has been directed toward introducing herbicide tolerance into normally susceptible crop species (9). Interest in developing herbicide-tolerant crop cultivars, clones, or hybrids (HTCs)3has been spurred by the reduction in the rate of discovery of new herbicidal compounds, the rising expense of developing new herbicides, and new tools of biotechnology that greatly increased our ability to develop HTC genotypes. Potential benefits of developing HTCs include: a) an increased margin of safety with which herbicides can be used with subsequent reduced crop losses due to herbicide injury, b) reduced risk of crop damage from residual herbicides from rotational crops, and c) introduction of new herbicides for use on normally susceptible crops. The last objective can be considered to be similar to breeding for resistance to diseases or insects. The most serious weed problems for a crop can be solved by developing crop tolerance to herbicides that control the weeds. This approach is particularly promising for minor crops for which new herbicide development is essentially lacking. However, the reluctance of herbicide manufacturers to register their products for minor crops may impede this approach. By developing tolerance to nontoxic, nonpolluting herbicides that are suitable for conservation tillage, the negative environmental effects of weed control can be reduced.
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Tucker, Jennifer J., M. Kimberly Mullenix, Stephen F. Enloe y Pat L. Burch. "Residual Herbicide Effect on Interseeded Annual Clover in Southern Forage Systems". Weed Technology 32, n.º 4 (11 de mayo de 2018): 454–60. http://dx.doi.org/10.1017/wet.2018.20.
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AbstractAcross the southeastern United States, pyridine carboxylic acid herbicides are widely used for broadleaf weed control in permanent grass pastures. This family of herbicides has proved very successful for controlling most broadleaf weeds commonly present in southeastern pastures and hayfields. In the southern United States, producers have expressed concern when overseeding legume species into warm-season perennial sods following application of commonly used pyridine carboxylic acid herbicides, as legumes are generally highly sensitive to this herbicide family. Field experiments were established to evaluate two herbicide treatment programs (residual vs nonresidual) on crimson clover overseeded into bermudagrass sod. The residual herbicide program included aminopyralid plus 2,4-D (0.09 + 0.7 kg ae ha–1), and the nonresidual program included triclopyr plus fluroxypyr (0.63 + 0.21 kg ae ha–1) plus 2,4-D (1.12 kg ae ha–1). Herbicide programs were applied at two key timings: in spring (May) and early summer (June). Spring applications were also evaluated when used in single vs repeated annual application. Our results did not indicate soil residual herbicide issues for crimson clover planted in the fall following spring or early-summer application of aminopyralid + 2,4-D at either location. Additionally, there were no cumulative negative impacts on crimson clover following 2 yr of spring herbicide application. Crimson clover cover, however, strongly decreased as grass and weed cover increased––an event that may be related to greater interspecific competition at higher levels of grass and weed cover. Soil fertility, weather, and competition from resident annual grasses and weeds strongly influenced productivity, suggesting that changes in pasture dynamics had a greater influence on clover productivity than did herbicide treatment or timing of application.
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Gulden, Robert H., Derek W. Lewis, Jane C. Froese, Rene C. Van Acker, Gary B. Martens, Martin H. Entz, Doug A. Derksen y Lindsay W. Bell. "The Effect of Rotation and In-Crop Weed Management on the Germinable Weed Seedbank after 10 Years". Weed Science 59, n.º 4 (diciembre de 2011): 553–61. http://dx.doi.org/10.1614/ws-d-11-00001.1.
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Agricultural production systems that reduce the use of in-crop herbicides could greatly reduce risks of environmental damage and the development of herbicide-resistant weeds. Few studies have investigated the long-term effects of in-crop herbicide omissions on weed seedbank community size and structure. A crop-rotation study was sampled 10 yr after a strictly annual rotation and an annual/perennial rotation were exposed to different in-crop herbicide omission treatments. In-crop herbicides were applied either in all annual crops (control), omitted from oats only, or omitted from both flax and oats. Seedbank densities were greatest when in-crop herbicides were omitted from flax and oats, and this treatment also reduced crop yield. Shannon-Wiener diversity differed among crops in the annual crop rotation and among herbicide omission treatments in the perennial rotation. Herbicide omissions changed the weed-community structure in flax and in wheat and canola crops in the annual rotation enough to warrant alternate control methods in some treatments. The magnitude of the effects on the seedbank parameters depended largely on the competitive ability of the crop in which herbicides were omitted. No yield response to omitting herbicides in oats indicated that standard weed management practices have reduced weed populations below yield-loss thresholds.
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Baier, Fabian, Edith Gruber, Thomas Hein, Elisabeth Bondar-Kunze, Marina Ivanković, Axel Mentler, Carsten A. Brühl, Bernhard Spangl y Johann G. Zaller. "Non-target effects of a glyphosate-based herbicide on Common toad larvae (Bufo bufo, Amphibia) and associated algae are altered by temperature". PeerJ 4 (1 de noviembre de 2016): e2641. http://dx.doi.org/10.7717/peerj.2641.
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BackgroundGlyphosate-based herbicides are the most widely used pesticides in agriculture, horticulture, municipalities and private gardens that can potentially contaminate nearby water bodies inhabited by amphibians and algae. Moreover, the development and diversity of these aquatic organisms could also be affected by human-induced climate change that might lead to more periods with extreme temperatures. However, to what extent non-target effects of these herbicides on amphibians or algae are altered by varying temperature is not well known.MethodsWe studied effects of five concentrations of the glyphosate-based herbicide formulation Roundup PowerFlex (0, 1.5, 3, 4 mg acid equivalent glyphosate L−1as a one time addition and a pulse treatment of totally 4 mg a.e. glyphosate L−1) on larval development of Common toads (Bufo bufo, L.; Amphibia: Anura) and associated algae communities under two temperature regimes (15 vs. 20 °C).ResultsHerbicide contamination reduced tail growth (−8%), induced the occurrence of tail deformations (i.e. lacerated or crooked tails) and reduced algae diversity (−6%). Higher water temperature increased tadpole growth (tail and body length (tl/bl) +66%, length-to-width ratio +4%) and decreased algae diversity (−21%). No clear relation between herbicide concentrations and tadpole growth or algae density or diversity was observed. Interactive effects of herbicides and temperature affected growth parameters, tail deformation and tadpole mortality indicating that the herbicide effects are temperature-dependent. Remarkably, herbicide-temperature interactions resulted in deformed tails in 34% of all herbicide treated tadpoles at 15 °C whereas no tail deformations were observed for the herbicide-free control at 15 °C or any tadpole at 20 °C; herbicide-induced mortality was higher at 15 °C but lower at 20 °C.DiscussionThese herbicide- and temperature-induced changes may have decided effects on ecological interactions in freshwater ecosystems. Although no clear dose-response effect was seen, the presence of glyphosate was decisive for an effect, suggesting that the lowest observed effect concentration (LOEC) in our study was 1.5 mg a.e. glyphosate L−1water. Overall, our findings also question the relevance of pesticide risk assessments conducted at standard temperatures.
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Soliman, Ibrahim y Amany Hamza. "Evaluation of Some Herbicides Against Flax Dodder (Cuscuta Epilinum Weihe) In Fibre Flax (Linum Ustatissimum L.) Cultivation". Journal of Plant Protection Research 50, n.º 3 (1 de septiembre de 2010): 372–78. http://dx.doi.org/10.2478/v10045-010-0063-8.
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Evaluation of Some Herbicides Against Flax Dodder (Cuscuta EpilinumWeihe) In Fibre Flax (Linum UstatissimumL.) CultivationTwo field experiments were carried out in Sakha Experimental Station during two seasons to evaluate the efficacy of different treatments (hand combing, butralin, tribenuron-methyl, metosulam and fluazifop-p-butyl) in controlling dodder weed (Cuscuta epilinumWeihe) in Fibre flax. Moreover, the effect of these treatments on some growth characters of flax yield and its components was also determined. All tested herbicide treatments decreased the dodder infestation in flax for up to 49 days. All tested herbicide treatments increased all flax growth characters, (straw yield and seed yield). Butralin herbicide gave the best control of dodder, followed by metosulam, tribenuron-methyl and fluazifop-p-butyl. Also, the data revealed that most herbicidal treatments slightly decreased protein content of flax plants and did not adversely affect the oil content of its seeds. This study suggests that, under heavy infestation of dodder weed, the use of the tested herbicides, especially butralin, is highly recommended.
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McMullan, Patrick M. "Grass Herbicide Efficacy as Influenced by Adjuvant, Spray Solution pH, and Ultraviolet Light". Weed Technology 10, n.º 1 (marzo de 1996): 72–77. http://dx.doi.org/10.1017/s0890037x00045735.
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Research was conducted at the Brandon Research Centre to determine the effect of spray solution pH or adjuvants on the efficacy of two cyclohexanedione (CHD) herbicides, clethodim and tralkoxydim, and two aryloxyphenoxypropionate (APP) herbicides, fenoxaprop-P and quizalofop, and if ultraviolet light is a factor influencing their activity. CHD herbicide efficacy decreased as spray solution pH increased above 7. APP herbicide efficacy was not affected by spray solution pH, probably due to their formulation as proherbicide esters. The choice of adjuvant affected CHD herbicide efficacy but not APP herbicide efficacy. Amigo®, Canplus-411® plus ammonium sulfate, and Merge® were usually the most effective adjuvants with the two CHD herbicides. Physical removal of ultraviolet light did not improve APP herbicide efficacy but did improve CHD herbicide efficacy.
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Ali, Abid, Guy Kateta Malangisha, Haiyang Yang, Chen Li, Chi Wang, Yubin Yang, Ahmed Mahmoud et al. "Strigolactone Alleviates Herbicide Toxicity via Maintaining Antioxidant Homeostasis in Watermelon (Citrullus lanatus)". Agriculture 11, n.º 5 (6 de mayo de 2021): 419. http://dx.doi.org/10.3390/agriculture11050419.
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Strigolactone (SL) plays essential roles in regulating plant growth, development, and stress response. This study was conducted to evaluate the effect of exogenous SL on watermelon resistance against herbicides penoxsulam (PXL) and bensulfuron-methyl (BSM). These herbicides were found to negatively impact watermelon root growth and photosynthetic pigments, probably due to the ultrastructural damage and cell death in leaf and root tissues under herbicide stresses. The activation of SL-related gene expression suggested that the SL pathway may mitigate herbicide toxicity in watermelon. The exogenous SL dose-dependently reversed the PXL- or BSM-induced antioxidant activity, suggesting that SL may participate in maintaining antioxidant enzyme homeostasis under herbicide stresses. The up-regulation of herbicide metabolization and detoxification-related genes (cytochrome P450 and acetolactate synthase) by exogenous SL also in part explained how this phytohormone alleviates herbicide toxicity in watermelon. Our findings will provide valuable information underlying the regulatory effects of SL on herbicide tolerance in Cucurbitaceae crops.
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Reichard, S. L., R. M. Sulc, L. H. Rhodes y M. M. Loux. "Effects of Herbicides on Sclerotinia Crown and Stem Rot of Alfalfa". Plant Disease 81, n.º 7 (julio de 1997): 787–90. http://dx.doi.org/10.1094/pdis.1997.81.7.787.
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This study was conducted to determine whether herbicides and adjuvants registered for poste-mergence use in alfalfa have an effect on Sclerotinia crown and stem rot (SCSR). In a controlled environment, disease severity index (DSI) of alfalfa seedlings was reduced by pronamide and 2,4-DB compared with the untreated control, whereas bromoxynil and 13% sethoxydim + petroleum-based adjuvant (PBA) increased DSI. In the field, disease severity in all herbicide treatments was similar to that in untreated alfalfa. In a second controlled-environment study, pronamide and 2,4-DB reduced DSI compared with the no herbicide control when seedlings were inoculated 1 day after herbicide application, but this protective effect was not observed when seedlings were inoculated 8 days or longer after herbicide application. The results demonstrate that several herbicides are capable of suppressing or enhancing SCSR severity in a controlled environment if seedling inoculation occurs soon after herbicide application; however, the residual effect of these herbicides on SCSR appeared to be much shorter than the 4- to 6-week infection period occurring in the field.
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Jiří, Andr, Kočárek Martin, Jursík Miroslav, Fendrychová Veronika y Tichý Lukáš. "Effect of adjuvants on the dissipation, efficacy and selectivity of three different pre-emergent sunflower herbicides". Plant, Soil and Environment 63, No. 9 (26 de septiembre de 2017): 409–15. http://dx.doi.org/10.17221/365/2017-pse.
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The aim of this work was to compare the efficacy, selectivity to sunflower and dissipation of three pre-emergent herbicides. Flurochloridone, linuron and oxyfluorfen were applied individually and each herbicide was also applied in a tank mix with two different adjuvants (a silicon-based adjuvant and paraffin oil). Small-plot field trials were carried out with sunflower in Central Bohemia in 2012 and 2015. Around 25–35% of the active ingredients in the applied herbicides were detected in soil 60 days after application in both years, except for oxyfluorfen in 2012, whose residual concentration was 60%. The tested soil adjuvants did not affect the dissipation of any of the tested herbicide in soil in either experimental year. Oxyfluorfen exhibited the highest mobility and caused the greatest degree of sunflower injury (18%), especially in the year with high rainfall shortly after application. None of the tested adjuvants significantly affected sunflower injury by any tested herbicide. The efficacy of flurochloridone and linuron on Fallopia convolvulus was strongly affected by weather conditions shortly after application. The efficacy of oxyfluorfen was around 85% and was not affected by weather conditions. The effect of adjuvant on herbicide efficacy was positive only in dry conditions, where the efficacy of flurochloridone on F. convolvulus was positively affected by the silicon-based adjuvant.
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Liu, Chun, Makhan Singh Bhullar, Tarundeep Kaur, Jitendra Kumar, Sriyapu Reddy Sreekanth Reddy, Manpreet Singh y Shiv Shankhar Kaundun. "Modelling the Effect and Variability of Integrated Weed Management of Phalaris minor in Rice-Wheat Cropping Systems in Northern India". Agronomy 11, n.º 11 (18 de noviembre de 2021): 2331. http://dx.doi.org/10.3390/agronomy11112331.
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Phalaris minor Retz. (littleseed canarygrass) is the most problematic and herbicide-resistant weed in the rice-wheat cropping system in India. As such, it poses a severe threat to wheat yield and food security. A number of herbicidal and agronomic practices have been identified for the effective control of P. minor. These include crop rotation, crop establishment methods, herbicide spray technology, sowing time, weed seed harvest and effective herbicide mixtures. A population model of P. minor was built based on the life cycle of the species, herbicide resistance mechanisms and the effects of weed control practices. The model simulated the interactions of these factors and provided the best management recommendations for sustainably controlling this noxious weed species. Model results indicate that integration of chemical and non-chemical control methods was the most effective and sustainable strategy. For example, the integration of a happy seeder (a tractor-mounted mulching and sowing machine) with an effective post-emergence herbicide reduced the probability of weed control failure by 32% compared to the scenario with a rotavator and the same herbicide. Similarly, more conventional crop establishment methods such as a rotavator and conventional tillage could be accompanied by pre- or post-emergence applications of herbicide mixtures. Adoption of good herbicide spray technology and weed seed harvest delayed the onset of resistance evolution by up to four years. Furthermore, effective crop rotation such as the inclusion of sugarcane in place of rice in the summer season reduced the risk of resistance evolution by 31% within the 10 year simulation period. In addition to the scenarios using representative parameter values, the variability of model predictions was investigated based on some field experiments. The model provided a powerful tool for promoting Integrated Weed Management and the sustainable use of herbicides. Pragmatic ways of dealing with uncertainty in model prediction are discussed.
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Takano, Hudson K., Roland Beffa, Christopher Preston, Philip Westra y Franck E. Dayan. "Glufosinate enhances the activity of protoporphyrinogen oxidase inhibitors". Weed Science 68, n.º 4 (12 de mayo de 2020): 324–32. http://dx.doi.org/10.1017/wsc.2020.39.
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AbstractGlufosinate inhibits glutamine synthetase (GS), a key enzyme for amino acid metabolism and photorespiration. Protoporphyrinogen oxidase (PPO) inhibitors block chlorophyll biosynthesis and cause protoporphyrin accumulation, a highly photodynamic intermediate. Both herbicides ultimately lead to plant death by a massive accumulation of reactive oxygen species (ROS) through different mechanisms. We investigated a potential synergistic effect by the mixture of the two herbicide mechanisms of action (MoAs). The tank mix between a low rate of glufosinate (280 g ai ha−1) with an ultra-low dose of saflufenacil (1 g ha−1) provided enhanced herbicidal activity compared with the products applied individually on Palmer amaranth (Amaranthus palmeri S. Watson). The synergism between the two herbicides was also confirmed by isobole analysis and field trials. The herbicide combination provided high levels of efficacy when applied at low temperature and low humidity. Mechanistically, glufosinate caused a transient accumulation of glutamate, the building block for chlorophyll biosynthesis. Consequently, inhibition of both GS and PPO resulted in greater accumulation of protoporphyrin and ROS, forming the physiological basis for the synergism between glufosinate and PPO inhibitors. While the synergy between the two herbicide MoAs provided excellent efficacy on weeds, it caused low injury to PPO-resistant waterhemp [Amaranthus tuberculatus (Moq.) Sauer] and high injury to both glufosinate-resistant and glufosinate-susceptible soybean [Glycine max (L.) Merr.]. Glufosinate enhances the activity of PPO inhibitors through glutamate and protoporphyrin accumulation, leading to increased levels of ROS and lipid peroxidation. The synergism between the two herbicide MoAs can help to overcome environmental effects limiting the efficacy of glufosinate. Future research is needed to optimize the uses for this herbicidal composition across different cropping systems.
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Campbell, MH, BR Milne, JJ Dellow y HI Nicol. "Effect of herbicides on St John's wort (Hypericum perforatum L.)". Australian Journal of Experimental Agriculture 31, n.º 4 (1991): 499. http://dx.doi.org/10.1071/ea9910499.
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The effect of type of herbicide and time and rate of application on the reduction in ground cover of St John's wort (Hypericum perforatum L.) was determined at Orange, New South Wales. In January, April, July and November 1988, 8 herbicide treatments including the currently used glyphosate and picloram + 2,4-D were applied to vigorously growing H. perforaturn, and the reduction in percentage ground cover was recorded in December 1989. Ineffective herbicides (a.i./ha) were tebuthiuron, 0.8-6.4 kg; metsulfuron, 5-20 g; and paraquat + diquat, 0.4 + 0.5 kg. The addition of metsulfuron (2.5 g a.i./ha) to glyphosate (0.9 and 1.8 kg a.i./ha) did not increase the effectiveness of the latter. Effective herbicides (kg a.i./ha) were triclopyr + picloram, 0.6 + 0.2; picloram + 2,4-D, 0.2 + 0.8; glyphosate, 1.8; and triclopyr, 1.92. There was a strong trend for these herbicides to be more effective in January and November than in April and July. Based on price, effectiveness and selectivity, triclopyr + picloram would be preferred to the other herbicides for boom and spot spraying, and glyphosate would be the only herbicide suitable for aerial application prior to sowing improved pastures on non-arable land.
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Loux, Mark M., Anthony F. Dobbels, Kevin W. Bradley, William G. Johnson, Bryan G. Young, Douglas J. Spaunhorst, Jason K. Norsworthy, Matheus Palhano y Lawrence E. Steckel. "Influence of Cover Crops on Management of Amaranthus Species in Glyphosate- and Glufosinate-Resistant Soybean". Weed Technology 31, n.º 4 (agosto de 2017): 487–95. http://dx.doi.org/10.1017/wet.2017.30.
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A field study was conducted for the 2014 and 2015 growing season in Arkansas, Indiana, Illinois, Missouri, Ohio, and Tennessee to determine the effect of cereal rye and either oats, radish, or annual ryegrass on the control of Amaranthus spp. when integrated with comprehensive herbicide programs in glyphosate-resistant and glufosinate-resistant soybean. Amaranthus species included redroot pigweed, waterhemp, and Palmer amaranth. The two herbicide programs included were: a PRE residual herbicide followed by POST application of foliar and residual herbicide (PRE/POST); or PRE residual herbicide followed by POST application of foliar and residual herbicide, followed by another POST application of residual herbicide (PRE/POST/POST). Control was not affected by type of soybean resistance trait. At the end of the season, herbicides controlled 100 and 96% of the redroot pigweed and Palmer amaranth, respectively, versus 49 and 29% in the absence of herbicides, averaged over sites and other factors. The PRE/POST and PRE/POST/POST herbicide treatments controlled 83 and 90% of waterhemp at the end of the season, respectively, versus 14% without herbicide. Cover crop treatments affected control of waterhemp and Palmer amaranth and soybean yield, only in the absence of herbicides. The rye cover crop consistently reduced Amaranthus spp. density in the absence of herbicides compared to no cover treatment.
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Mosqueda, Elizabeth G., Charlemagne A. Lim, Gustavo M. Sbatella, Prashant Jha, Nevin C. Lawrence y Andrew R. Kniss. "Effect of crop canopy and herbicide application on kochia (Bassia scoparia) density and seed production". Weed Science 68, n.º 3 (25 de marzo de 2020): 278–84. http://dx.doi.org/10.1017/wsc.2020.23.
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AbstractUnderstanding the effects of crop management practices on weed survival and seed production is imperative in improving long-term weed management strategies, especially for herbicide-resistant weed populations. Kochia [Bassia scoparia (L.) A.J. Scott] is an economically important weed in western North American cropping systems for many reasons, including prolific seed production and evolved resistance to numerous herbicide sites of action. Field studies were conducted in 2014 in a total of four field sites in Wyoming, Montana, and Nebraska to quantify the impact of different crop canopies and herbicide applications on B. scoparia density and seed production. Crops used in this study were spring wheat (Triticum aestivum L.), dry bean (Phaseolus vulgaris L.), sugar beet (Beta vulgaris L.), and corn (Zea mays L.). Herbicide treatments included either acetolactate synthase (ALS) inhibitors effective on non-resistant B. scoparia or a non–ALS inhibiting herbicide effective for both ALS-resistant and ALS-susceptible B. scoparia. Bassia scoparia density midseason was affected more by herbicide choice than by crop canopy, whereas B. scoparia seed production per plant was affected more by crop canopy compared with herbicide treatment. Our results suggest that crop canopy and herbicide treatments were both influential on B. scoparia seed production per unit area, which is likely a key indicator of long-term management success for this annual weed species. The lowest germinable seed production per unit area was observed in spring wheat treated with non–ALS inhibiting herbicides, and the greatest germinable seed production was observed in sugar beet treated with ALS-inhibiting herbicides. The combined effects of crop canopy and herbicide treatment can minimize B. scoparia establishment and seed production.
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ALVARENGA, DOUGLAS RODRIGUES, MATHEUS FERREIRA FRANÇA TEIXEIRA, FRANCISCO CLAUDIO LOPES DE FREITAS, MARIA CAROLINA GOMES PAIVA, MARIANA RACHEL NASCIMENTO CARVALHO y VALDINEI ARAÚJO GONÇALVES. "INTERAÇÕES ENTRE HERBICIDAS NO MANEJO DO MILHO RR® VOLUNTÁRIO". Revista Brasileira de Milho e Sorgo 17, n.º 1 (31 de marzo de 2018): 122. http://dx.doi.org/10.18512/1980-6477/rbms.v17n1p122-134.
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RESUMO - A mistura entre herbicidas pode resultar em efeitos sinérgicos, antagônicos ou aditivos no controle do milho voluntário e de outras espécies de plantas daninhas. Objetivou-se com este trabalho avaliar a eficiência de diferentes doses do fluazifop-p-butil isolado e na associação com os herbicidas glyphosate, 2,4-D e a mistura glyphosate + 2,4-D. O experimento foi conduzido em vasos contendo cinco litros de solo, com seis doses do herbicida fluazifopp- butil aplicadas em mistura com três herbicidas/mistura [glyphosate, 2,4-D e glyphosate + 2,4-D] em três formas de aplicação (mistura em tanque, aplicados separadamente no mesmo dia e separadamente cinco dias antes da aplicação do fluazipop-p-butil), mais as seis doses do fluazifop-p-butil sem mistura. Verificou-se que o herbicida fluazifop-pbutil aplicado isoladamente controla de modo eficiente plantas voluntárias de híbrido de milho AS 1660 PRO RR nas doses 75 g ha-1, 28 dias após a aplicação (DAA). Porém, a mistura em tanque do fluazifop-p-butil com 2,4-D resultou em redução do nível de controle do milho voluntário. Não houve redução da eficácia no controle do milho quando se aplicou o herbicida fluazifop-p-butil associado ao glyphosate, 2,4-D e a mistura glyphosate + 2,4-D, separadamente no mesmo dia ou cinco dias após.Palavras-chave: antagonismo, fluazifop-p-butil, glyphosate, 2,4-D, Zea mays.INTERACTIONS AMONG HERBICIDES IN THE MANAGEMENT OF THE VOLUNTARY MAIZE RR®ABSTRACT - Mixing herbicides may result in synergistic, antagonistic or additive effects on the control of volunteer maize and other weed species. The objective of this work was to evaluate the efficiency of different doses of fluazifopp- butyl alone and in association with the herbicides glyphosate, 2,4-D and glyphosate + 2,4-D mixture. The experiment was carried out in pots containing five liters of soil, with six doses of the herbicide fluazifop-p-butyl applied in a mixture of three herbicides/mixture [glyphosate, 2,4-D and glyphosate + 2,4-D] (tank mix, applied separately on the same day and separately five days prior to the application of fluazipop-p-butyl) plus the six doses of fluazifop-p-butyl without mixing. The isolated fluazifop-p-butyl herbicide was monitored efficiently to control volunteer maize hybrids AS 1660 PRO RR at doses 75 g ha-1, 28 days after application (DAA). However, tank mixing of fluazifop-p-butyl with 2,4-D resulted in a reduction in the level of voluntary maize control. There was no reduction in efficacy in maize control when applied we the herbicide fluazifop-p-butyl associated with glyphosate, 2,4-D and glyphosate + 2,4-D mixture, separately on the same day or five days later.Keywords: antagonism, fluazifop-p-butyl, glyphosate, 2,4-D, Zea mays.
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Indarwati, Indarwati, Mochamad Thohiron y M. Fajri Triyono. "Uji Efektivitas Herbisida Pasca Tumbuh Pada Tanaman Kedelai (Glycine max. L)". Journal of Applied Plant Technology 1, n.º 1 (24 de noviembre de 2022): 71–82. http://dx.doi.org/10.30742/japt.v1i1.32.
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The purpose of this study was to determine the effect of weed control with herbicides on soybean growth and yield. This research was conducted in the Mojosari Agricultural Experimental Garden, Mojokerto, March - July 2021. The method used was a Randomized Block Design (RAK) with 3 treatments and 4 replications. The treatments were (P0) mechanical weeding (Control); (P1) Spraying herbicide 1X; (P2) spraying. 2X herbicide. selective herbicide spraying (Agil 100 ec) with the active ingredient propaquzafop 100 ec C-12 was carried out according to the treatment. Herbicide application had a better effect on soybean yields than control (mechanical weeding). However, spraying herbicides once had the same good effect as (P2) spraying 2X. The soybean plants tested were able to produce dry pods weight of 36.85 -39.00 g/plant, and dry weight 100 seeds 18,48-20,90 g.
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Samples, Chase Allen, Thomas R. Butts, Bruno C. Vieira, Jon Trenton Irby, Daniel B. Reynolds, Angus Catchot, Greg R. Kruger y Darrin M. Dodds. "Effect of Deposition Aids Tank-Mixed with Herbicides on Cotton and Soybean Canopy Deposition and Spray Droplet Parameters". Agronomy 11, n.º 2 (3 de febrero de 2021): 278. http://dx.doi.org/10.3390/agronomy11020278.
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The adoption of auxin-tolerant crops has increased awareness regarding herbicide off-target movement. Deposition aids are promoted as a possible solution to off-target movement, although their effect on spray canopy deposition are not well understood. Studies were conducted to determine the impact of deposition aids tank-mixed with herbicides on spray droplet size and canopy deposition. Commonly used herbicides were applied on soybean and cotton in combination with deposition aids (oil, polymer, and guargum). Interactions between herbicide solution and deposition aid influenced droplet size parameters for both cotton and soybean herbicides tested herein (p ≤ 0.0001). Generally, the addition of polymer and guargum deposition aids increased spray droplet size, whereas the addition of oil deposition aid decreased droplet size for some treatments. When herbicides were combined, the inclusion of deposition aids did not influence overall spray deposition on cotton (p = 0.82) and soybean (p = 0.72). When herbicide solutions were evaluated individually, the advent of deposition aids had inconsistent results with cotton and soybean spray deposition being unaffected, increased, or even decreased depending on the herbicide solution tested. For example, the polymer-based deposition aid increased spray deposition on cotton for applications of glyphosate + dicamba + S-metolachlor resulting in 1640.6 RFU (relative fluorescence units). However, the same deposition aid decreased spray deposition on cotton for applications of glyphosate + dicamba + acetochlor (1179.3 RFU). Although deposition aids influenced spray deposition on cotton and soybean for some herbicide combinations, their use should be determined on a case-by-case scenario.
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Brunton, David J., Peter Boutsalis, Gurjeet Gill y Christopher Preston. "Varying responses of field-selected herbicide-resistant rigid ryegrass (Lolium rigidum) populations to combinations of phorate with PPI herbicides". Weed Science 68, n.º 4 (13 de abril de 2020): 367–72. http://dx.doi.org/10.1017/wsc.2020.27.
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AbstractOrganophosphate insecticides, which have the capacity to inhibit specific herbicide-degrading (cytochrome P450) enzymes, have been used to explore metabolic herbicide-resistance mechanisms in weeds. This study investigates the response of seven field-selected rigid ryegrass (Lolium rigidum Gaudin) populations to herbicides from three different sites of action in the presence or absence of the P450 inhibitor phorate. Phorate antagonized the thiocarbamate herbicides triallate and prosulfocarb (8-fold increase in LD50) in multiple resistant L. rigidum populations with resistance to three different site-of-action herbicides. In contrast, phorate synergized trifluralin and propyzamide in some populations, reducing the LD50 by 50%. Conversely, treatment with phorate had no significant effect on the LD50 for S-metolachlor or pyroxasulfone (inhibitors of very-long-chain fatty-acid synthesis). Phorate has diverse effects that are herbicide and population dependant in field-selected L. rigidum, suggesting P450 involvement in the metabolism of trifluralin and failure to activate thiocarbamate herbicides in these populations. This research highlights the need for implementation of diverse approaches other than herbicide alone as part of a long-term integrated strategy to reduce the likelihood of metabolism-based resistance to PPI herbicides in L. rigidum.
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Okrushko, Svitlana. "ESTIMATION OF THE INFLUENCE OF HERBICIDES AND PGR OF ZEASTIMULIN ON WEEDING AND YIELD OF CORN". Agriculture and Forestry, n.º 2 (30 de octubre de 2020): 95–105. http://dx.doi.org/10.37128/2707-5826-2020-2-9.
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The system of protection of cultivated plants from the negative effects of weeds is an important element in the technology of growing corn. The application of the chemical method allows to effectively and for a long time get rid of the agrophytocenosis of weeds. Weeds significantly impair the growing conditions of cultivated plants and prevent them from realizing the opportunities inherent in the genetic potential of the crop. Maize has a low level of competitiveness against weeds. The aim of the article was: to substantiate the application of insurance herbicides Laudis and Stellar for weed control and their joint use with PGR Zeastimulin to increase corn grain yield. Medium-early maize hybrid PR39T45 FAO 250 was grown. It is characterized by good cold resistance and drought resistance. The size of the registered area of plots is 20 m2, repeated three times with a systematic arrangement of options. The predecessor of corn was potatoes. Herbicides and PGR Zeastimulin were applied in the phase of 3-4 leaves in corn. After treatment of crops with Laudis herbicide, weed accounting showed a decrease in the number of weeds by 89,7% compared to control. At the time of maize harvesting, Laudis reduced the level of weeding by 94,7% in quantity and by 655 g/m2 of mass compared to the natural background without the introduction of herbicides and growth regulator. The application of Stellar herbicide allowed better control of the number and weight of weeds, due to its effect on perennials. The decrease in weed numbers was 93,5% during the first survey, 97,0% during the second and 97,9% during the third. In the experimental variants, where herbicides were applied together with PGR Zeastimulin, no decrease in the number of weeds was observed, and only a slight decrease in the above-ground air-dry mass of weed plants was observed. The height of maize in the phase of 7-8 leaves on the herbicidal background was higher by 17,3% (var. 2) and 19,8% (var. 4) than on the control variant. Treatment of crops with Zeastimulin provided an increase of this indicator by another 2 cm. Due to the positive effect of the growth regulator, the length of maize cobs increased from 17,9 cm to 18,6 cm in the version of weed control by Laudis (0,5 kg/ha), and from 18,3 cm to 19,4 cm in the variant of herbicide application. Stellar (1,1 l/ha). In maize, the diameter of the cobs increased due to a decrease in the negative effects of weeds and under the influence of PGR Zeastimulin. Weed control in maize agrophytocenoses with Laudis herbicide (0,5 kg/ha) provided better conditions for cultivated plants, which gave a grain yield increase of 2,9 t/ha, and Stellar herbicide (1,1 l/ha) - for 3,1 t/ha. The application of Zeastimulin to maize crops increased the yield by 9,5% in the Laudis herbicide variant (0,5 kg/ha) and by 9,2% in the Stellar herbicide variant (1,1 l/ha). Further studies are planned to continue the assessment in maize agrophytocenoses of the effects of Laudis and Stellar herbicides on weed and PGR Zeastimulin under different weather conditions during the growing season. Key words: corn, weeds, herbicides, plant growth regulator, yield.
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Hamouz, P., K. Hamouzová, L. Tyšer y J. Holec. "Effect of site-specific weed management in winter crops on yield and weed populations". Plant, Soil and Environment 60, No. 1 (22 de enero de 2014): 27–35. http://dx.doi.org/10.17221/574/2013-pse.
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Site-specific weed management (SSWM) methods allow spatially variable treatment of weed populations according to actual weed abundance, thus offering the opportunity for herbicide savings. However, SSWM’s effect on weed population dynamics is not sufficiently understood. In this study, SSWM was conducted based on various application thresholds to analyse the effects on crop yield and weed infestation in the succeeding crop. SSWM was used on a 3.07 ha experimental field in winter wheat (2011) and winter oilseed rape (2012). The whole area was split into application cells of 6 × 10 m and abundance of all weed species was evaluated manually in each cell. Four different herbicide treatments were tested. Standard whole-field herbicide application (blanket spraying) was treatment 1.<br /> Treatments 2, 3 and 4 comprised SSWM using different thresholds for post-emergent herbicide application. SSWM resulted in savings of post-emergent herbicides ranging from 71.9% to 100%, depending on the application threshold. Differences in winter rape yield among treatments were generally small and statistically insignificant<br /> (P = 0.989). Although some minor changes in weed abundances were observable, the experiment showed that none of the site-specific herbicide treatments caused a significant (α = 0.05) increase of weed species abundance compared to the standard treatment.
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Kostyuk, A. V. y N. G. Lukacheva. "THE EFFECIENCY OF LEAF EFFECT HERBICIDES FOR CORN CROPS". Siberian Herald of Agricultural Science 48, n.º 4 (23 de octubre de 2018): 20–26. http://dx.doi.org/10.26898/0370-8799-2018-4-3.
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The efficiency of leaf effect herbicides in corn crops was studied. The study was carried out in 2001–2016 in the experimental fields of Primorye on brown meadow podzolized soils containing 3-4% of humus in the arable horizon. In 2001–2010 corn of hybrid population Slavyanka was sown and in 2015–2016 – ZPTK196, with a seeding rate of 70.000 seeds/ha. Herbicides Milagro (1.0 and 1.5 l/ha), Titus (0.04 kg/ha), Cordus (0.04 kg/ ha) and Doublon Gold (0.07 kg/ha) in tank mixture with Luvaram (0.82 l/ha) or Dianatom (0.4 l/ ha) enhanced the effect of preparations on weed plants, especially on common ragweed (Ambrosia artemisiifolia). Biological efficiency increased to 74–90%, and yield – by 0.43–1.80 t/ha. The use of herbicide Basis (0.02 and 0.025 kg/ha) led to the increase in corn grain yield to 1.43–2.06 t/ ha. Resistant to this herbicide was dayflower (Commelina communis), which, due to the lack of other weeds, increased the above-ground mass to 1.3 kg / m2.. The application of herbicide MaisTer provided the yield increase up to 2.09–2.41 t/ha. It was observed that for more reliable suppression of common ragweed, herbicide MaisTer (0.125 and 0.15 kg/ha) should be used no later than the phase of three pairs of leaves when the air temperature does not exceed 200C. The herbicides Titus Plus (0.34 and 0.38 kg/ha) and Stellar (1.5l/ ha) almost completely purified the corn from weeds, which contributed to the preservation of 2.07–3.59 t/ha of corn.
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Abdullahi, Kamala, Khalifa Jamil Saleh y Ignatius Mzungu. "Effect of Atrazine, 2,4-D Amine, Glyphosate and Paraquat Herbicides on Soil Microbial Population". Journal of Environmental Microbiology and Toxicology 10, n.º 1 (31 de julio de 2022): 19–22. http://dx.doi.org/10.54987/jemat.v10i1.693.
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Herbicides’ toxic impact on the non-target soil microorganisms which play roles in degrading organic matter, nitrogen and nutrient recycling and decomposition needs to be considered. In the present study, the effect of four (4) most commonly used herbicides, viz; atrazine, 2, 4- D amine, glyphosate and paraquat on soil microorganisms was assessed over a period of fifteen continuous days (exposure period). The herbicide treatments were the normal recommended field rate, (6.67 mg active ingredient per gram of soil for atrazine, 6.17 mg for 2, 4-D amine, 5.56 mg for glyphosate, and 2.46 mg for paraquat), half and double of the recommended field rates. Tables 4.1 through 4.5 showed the various heterotrophic bacterial colony counts obtained from the various treatments, ranging from the control (Day 1; no herbicide applied) to days 3, 6, 9 and 15 after the application of the various herbicides, respectively. Two general trends are readily observed: the first is that, upon application of the herbicide, the microbial growth steadily diminishes, up to the 6th day. However, from there it continues to increase till the end of the experiments (day 15). This applies to each herbicide. Firstly, the effect of the addition of the various herbicides was evaluated using two samples, a two-tailed Z-Test for means, at a 95% confidence interval, and the results showed that there is a difference in the bacterial counts before the application of the herbicides (Day 0) and immediately after (day 3), and the difference is statistically significant (Z = 3.32, Z critical = 1.96, P = 0.00090). This indicates that the application of the herbicides affects the bacterial population.
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Kurniadie, Denny, Uum Umiyati, Ryan Widianto y Hisashi Kato-Noguchi. "Effect of Chitosan Molecules on Paraquat Herbicidal Efficacy under Simulated Rainfall Conditions". Agronomy 12, n.º 7 (13 de julio de 2022): 1666. http://dx.doi.org/10.3390/agronomy12071666.
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Unexpected rainfall before herbicide absorption by plants can wash away herbicides from plant tissue surfaces, which may reduce the herbicidal efficacy and increase the adverse effects on nontarget organisms and the environment, including water networks. The objective of this study was the evaluation of the effect of chitosan on paraquat efficacy under simulated rainfall conditions. Simulated rainfall within 3 h after paraquat application decreased its herbicidal efficacy. A mixture of paraquat (280 g a.i./ha) and chitosan (0.05% w/v) significantly increased the herbicidal efficacy against Ageratum conyzoides L. (21% increase), Borreria alata Aubl. (15%) and Paspalum conjugatum Bergius (8%) under the rainfall conditions. The chemical structure of chitosan may contribute to the penetration of paraquat into plant tissues. However, a mixture of paraquat and chitosan did not affect the herbicidal efficacy against Imperata cylindrica (L.) Beauv. The morphological characteristics of I. cylindrica may interfere with the enhancement effect of chitosan. Chitosan is a degradable, nontoxic and easily available and low-cost material made from crustacean shells. These results suggest that chitosan may increase paraquat efficacy against some noxious weed species under rainfall conditions, which may reduce the risk of paraquat contamination into the environment. Therefore, the application of herbicides with chitosan may provide the economic and environmental benefits. Chitosan may enhance the efficacy of other herbicides under unexpected rainfall conditions; however, this possibility requires further investigation.
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Begitschke, Erick G., James D. McCurdy, Te-Ming Tseng, T. Casey Barickman, Barry R. Stewart, Christian M. Baldwin, Michael P. Richard y Maria Tomaso-Peterson. "Preemergence Herbicide Effects on Hybrid Bermudagrass Root Architecture and Establishment". HortScience 53, n.º 4 (abril de 2018): 567–72. http://dx.doi.org/10.21273/hortsci12480-17.
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Preemergence herbicides generally have a negative effect on hybrid bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy] establishment. However, little is known about the effect they have on root architecture and development. Research was conducted to determine the effects of commonly used preemergence herbicides on ‘Latitude 36’ hybrid bermudagrass root architecture and establishment. The experiment was conducted in a climate-controlled greenhouse maintained at 26 °C day/night temperature at Mississippi State University in Starkville, MS, from Apr. 2016 to June 2016 and repeated from July 2016 to Sept. 2016. Hybrid bermudagrass plugs (31.6 cm2) were planted in 126-cm2 pots (1120 cm3) and preemergence herbicide treatments were applied 1 d after planting at the recommended labeled rate for each herbicide. Preemergence herbicide treatments included atrazine, atrazine + S-metolachlor, dithiopyr, flumioxazin, indaziflam, liquid and granular applied oxadiazon, S-metolachlor, pendimethalin, prodiamine, and simazine. Treatments were arranged in a completely randomized design with four replications. Plugs treated with indaziflam and liquid applied oxadiazon failed to achieve 50% hybrid bermudagrass cover by the end of the experiment. Of the remaining herbicide treatments, all herbicides other than granular applied oxadiazon and atrazine increased the number of days required to reach 50% cover (Days50). In addition, all herbicide treatments reduced root mass when harvested 6 weeks after treatment (WAT) relative to the nontreated. By 10 WAT, all treatments reduced root mass in run 1, but during run 2, only prodiamine, pendimethalin, simazine, atrazine + S-metolachlor, liquid applied oxadiazon, and indaziflam reduced dry root mass compared with the nontreated. At 4 WAT, all treatments other than simazine and granular applied oxadiazon reduced root length when compared with the nontreated. By 10 WAT, only dithiopyr, S-metolachlor alone, and indaziflam reduced root length when compared with the nontreated. No differences were detected in the total amounts of nonstarch nonstructural carbohydrates (TNSC) within the roots in either run of the experiment. Results suggest that indaziflam, dithiopyr, and S-metolachlor are not safe on newly established hybrid bermudagrass and should be avoided during establishment. For all other treatments, hybrid bermudagrass roots were able to recover from initial herbicidal injury by 10 WAT; however, future research should evaluate tensile strength of treated sod.
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Buhler, Douglas D. "Effect of ridge truncation on weed populations and control in ridge-tillage corn (Zea mays)". Weed Science 46, n.º 2 (abril de 1998): 225–30. http://dx.doi.org/10.1017/s0043174500090469.
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Ridge truncation methods affected weed populations, weed control, and corn yields in a ridge-tillage production system. Ridges were left undisturbed, partially truncated, deeply truncated, or destroyed by full-width tillage. The effect of truncation on weed densities and control (visual estimates of biomass reduction) varied by weed species, herbicide treatment, and time of observation. Without herbicide, deep truncation resulted in the lowest densities of all species except giant foxtail. Band application of herbicide controlled all weed species as well as broadcast application following deep truncation. When herbicides were broadcast, weed control was usually not affected by ridge truncation. Ridge truncation often increased corn yields compared with no truncation due to better weed control. While deep truncation often resulted in lower weed populations following herbicide treatment than shallow truncation or disking, differences were not great enough to affect corn yields. When ridges were truncated, broadcast herbicide did not increase corn yields compared with banded herbicide.
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Peterson, Dallas E. "The Impact of Herbicide-Resistant Weeds on Kansas Agriculture". Weed Technology 13, n.º 3 (septiembre de 1999): 632–35. http://dx.doi.org/10.1017/s0890037x00046315.
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Herbicides are important components of weed management programs for most Kansas farmers. Monocropping systems and repeated use of the same or similar herbicides in some areas of the state have resulted in the development of herbicide-resistant weeds. The development of herbicide-resistant weed populations can have an immediate and a long-term effect on the cost, implementation, and effectiveness of weed control programs. In Kansas, resistance to triazine herbicides has been confirmed in kochia (Kochia scoparia), redroot pigweed, common waterhemp (Amaranthus rudis), Palmer amaranth (Amaranthus palmeri), and downy brome (Bromus tectorum) populations, and resistance to acetolactate synthase (ALS)-inhibiting herbicides has been confirmed in kochia, Russian thistle (Salsola kali), common waterhemp, Palmer amaranth, common cocklebur (Xanthium strumarium), shattercane (Sorghum bicolor), and common sunflower (Helianthus annum). The frequency and distribution of herbicide resistance varies among species. Producers who experience herbicide resistance problems adjust their weed control program accordingly. Producers that have not encountered an herbicide resistance problem tend to continue with a successful herbicide program until it fails. The recommended management strategies for herbicide-resistant weed populations include an integrated system of crop rotation, rotation of herbicide modes of action, tank-mixes of herbicides with different modes of action, and cultivation. The greatest direct cost to the producer occurs during the first year of poor weed control. The first response to an herbicide failure often is to reapply the same herbicide that has worked well previously. By the time the producer realizes that the treatment is not going to work, it usually is too late for any other remedial action. Consequently, the farmer experiences reduced crop production from weed competition, high herbicide costs, and a tremendous increase in the seed bank. The increase in seed bank may cost the farmer the most in the long run because the increased weed pressure often requires an intensified control program for several years.
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Messelhäuser, Miriam, Marcus Saile, Bernd Sievernich y Roland Gerhards. "Effect of cinmethylin against Alopecurus myosuroides Huds. in winter cereals". Plant, Soil and Environment 67, No. 1 (11 de enero de 2021): 46–54. http://dx.doi.org/10.17221/586/2020-pse.
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Cinmethylin is a potential new pre-emergence herbicide in Europe inhibiting the fatty acid thioesterases in the plastid against Alopecurus myosuroides and other grass-weeds in winter cereals and oil-seed rape. Five field experiments were conducted in Southwestern Germany from 2018 until 2020 to assess the control efficacy of cinmethylin and other common pre-emergence herbicides alone and combined with post-emergence herbicides against A. myosuroides and yield response of winter wheat and winter triticale. In four experiments, the effect of early and late sowing of winter cereals was included as the second factor in the experiment to investigate if late sowing can reduce A. myosuroides density weed control efficacy. All fields were heavily infested with A. myosuroides with average<br /> densities of 110–730 plants/m<sup>2</sup>. Late sowing reduced densities in three out of four experiments. Herbicides controlled 42–100% of the A. myosuroides plants. However, none of the treatments was consistently better than the other treatments over all experiments. In three out of 5 experiments, grain yields were significantly increased by the herbicide treatments. The results demonstrate that cinmethylin increases the options for controlling A. myosuroides in winter cereals. However, it needs to be combined with other control tactics.
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Ariunaa, O., M. Otgonsuren y N. Bayarsukh. "Effect of herbicides applied against of weeds in soybean (Glycine max L.) field". Mongolian Journal of Agricultural Sciences 11, n.º 2 (24 de noviembre de 2014): 59–62. http://dx.doi.org/10.5564/mjas.v11i2.218.
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Herbicides, if used properly, are safe and effective in controlling weeds in soybean. The choice of herbicide, however, depends on the predominant weed species and the availability of the herbicide. In soybean field distributed 21 species of weedsof 20 genus belonging to 14 families, that are the determined 71.5% annual, 9.5% biennialweeds and 19.0% perennial weeds. Herbicides are available for pre-emergence or post emergence weed control in soybean. For examining testable variations, 278 weeds in 1m2 area were counted awet weight 1000 g, a dry weight 138.1 referring to weed density at the highestdoses 1.5-2.0 L of Targonherbicide applied in variations, whereas 92 weeds in 1m2 area were counted a wet weight 575 g, a dry weight 120.1 were to rubbish most lesser Gallant superherbicide doses at 0.45-0.65 L/ha applied in variations. In soybean field for controlling to weeds were applied Targon herbicide at doses 1.0-2.0l/ha , whereas weed species density reduced by 91.4-93.2% and the weight by 47.2-59.7%, Gallant super herbicide at doses 0.45-0.65 l/ha,the weed species density reduced by 91.1-96.3, and the weight by 37.3-58.9%, Cobra herbicide at doses 0.45-0.55 l/ha that weed species density reduced by 90.2- 95.0% and the weight by 36.7-41.4%, Flex herbicide at doses 1.65-1.85 l/ha that weed species density reduced by 95.6-94.6% and the weight by 31.2-32.5 percent respectively. The effect of chemical weed control with reduced herbicide doses on the weed population density in soybean yield was observed. Weed competition has reduced an important morpho-physiological trait in soybean. DOI: http://dx.doi.org/10.5564/mjas.v11i2.218 Mongolian Journal of Agricultural Sciences Vol.11(2) 2013 pp.59-62
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Gilliam, C. H., D. J. Eakes, J. W. Olive y M. Thetford. "HERBICIDE USE IN PROPAGATION". HortScience 26, n.º 5 (mayo de 1991): 485d—485. http://dx.doi.org/10.21273/hortsci.26.5.485d.
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Two experiments were conducted to evaluate commonly used granular preemergence herbicides applied prior to the sticking of cuttings in propagation. Rooting percentage of the three cultivars, `Trouper' azalea, `Hino-Crimson' azalea, and `August Beauty' gardenia, was not affected in experiment 1. However, all three species exhibited some reduction in root quality or root length with all herbicides. In general, the herbicides with the least suppression were: Ronstar, Southern WeedGrass Control, OH-2, Snapshot 2.5 TG, and Rout. The second experiment with `August Beauty' gardenia evaluated the effect of cuttings depth in overcoming the negative herbicide effects on root development. The results were similar to those obtained in experiment 1.
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Benedetti, Lariza, Gulab Rangani, Vívian Ebeling Viana, Pâmela Carvalho-Moore, Aldo Merotto, Edinalvo Rabaioli Camargo, Luis Antonio de Avila y Nilda Roma-Burgos. "Rapid Reduction of Herbicide Susceptibility in Junglerice by Recurrent Selection with Sublethal Dose of Herbicides and Heat Stress". Agronomy 10, n.º 11 (12 de noviembre de 2020): 1761. http://dx.doi.org/10.3390/agronomy10111761.
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Global climate change, specifically rising temperature, can alter the molecular physiology of weedy plants. These changes affect herbicide efficacy and weed management. This research aimed to investigate the combined effect of heat stress (HS) and sublethal doses of herbicides (four active ingredients) on adaptive gene expression and efficacy of herbicide on Echinochloa colona (L.) Link (junglerice). Three factors were evaluated; factor A was E. colona generation (G0-original population from susceptible standard; G1 and G2 were progenies of recurrent selection), factor B was herbicide treatment (florpyrauxifen-benzyl, glufosinate-ammonium, imazethapyr, quinclorac and nontreated check) and factor C was HS (30 and 45 °C). The herbicides were applied at 0.125× the recommended dose. Recurrent exposure to HS, combined with sublethal doses of herbicides, favors the selection of plants less susceptible to the herbicide. Upregulation of defense (antioxidant) genes (APX: Ascorbate peroxidase), herbicide detoxification genes (CYP450 family: Cytochrome P450), stress acclimation genes (HSP: Heat shock protein, TPP: Trehalose phosphate phosphatase and TPS: Trehalose phosphate synthase) and genes related to herbicide conjugation (UGT: UDP Glucosyltransferase) was significant. The positive regulation of these genes may promote increased tolerance of E. colona to these herbicides.
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Nunes, Anderson Luis y Ribas Antonio Vidal. "Leaching of the S-metolachlor herbicide associated with paraquat or glyphosate in a no-tillage system". Pesquisa Agropecuária Tropical 46, n.º 3 (septiembre de 2016): 254–58. http://dx.doi.org/10.1590/1983-40632016v4640405.
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ABSTRACT The combined use of desiccant and residual herbicides is a common management practice under no-tillage systems. However, the effect of desiccant herbicides and mulch on the leaching of residual herbicide is unknown. This study aimed at assessing the leaching of the S-metolachlor herbicide applied to ryegrass sequentially or in association with paraquat or glyphosate. A randomized blocks design was used, with four repetitions and treatments distributed over split-plots. The desiccant herbicides paraquat (600 g ha-1) or glyphosate (720 g ha-1) were used in the main plot, while S-metolachlor (2,800 g ha-1) was applied sequentially or in association with the desiccant herbicides in the subplots. There was also a control containing only desiccant herbicide, with no application of residual herbicide. The type of desiccant did not affect the leaching of the residual herbicide. In addition, the chosen method to apply the residual herbicide, sequentially or in association with the desiccant, did not impact the S-metolachlor behavior in the soil. The bioavailable concentration in the soil, 25 days after the application, was 90 g a.i. ha-1, at a depth of 18 cm.
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Sarathambal, C., V. P. Singh y K. K. Barman. "Soil microbial communities and enzymes as affected by herbicides of rice-wheat and soybean- wheat cropping system". Journal of Applied and Natural Science 7, n.º 2 (1 de diciembre de 2015): 935–38. http://dx.doi.org/10.31018/jans.v7i2.710.
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A field study was conducted to study the long term impact of continuous use of herbicide on microbial activity in rice-wheat and soybean- wheat cropping system. In the present investigation, non herbicide treatments such as hand weeding and weedy check showed higher activity as compared with herbicide receiving treatments. In rice, among the two herbicides, application of butachlor had less adverse effect when compared to the application of anilophos on soil microorganisms. Actinomycetes population maintained stable after the application of herbicides. Among the different herbicide application practices, maximum dehydrogenase activity (27.7µg TPF/g soil/24hrs) and urease activity (44.5µg NH4/g soil/24hrs) was observed in anilophos and butachlor treatment respectively. The treatment preceding wheat crop did not influence the microbial and enzyme activities. In soybean, highest population of total bacteria (3.34×106cfu/g) and actinomycetes (2.47×103 cfu/g) were observed in one hand weeding treatment. The treatment preceding wheat crop did not influence the basic microbial activities. However, it positively influenced dehydrogenase activity in all the three rabi season herbicides. This study clearly indicated that herbicide application had not significant effect on the soil microbial population and soil enzymes.
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Rosculete, Catalin, Elena Bonciu, Elena Rosculete y Liviu Olaru. "Determination of the Environmental Pollution Potential of Some Herbicides by the Assessment of Cytotoxic and Genotoxic Effects on Allium cepa". International Journal of Environmental Research and Public Health 16, n.º 1 (28 de diciembre de 2018): 75. http://dx.doi.org/10.3390/ijerph16010075.
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The present study aims to evaluate the potential for the pollution of the environment by two herbicides (quizalofop-p-ethyl and cycloxydim), using the Allium test. The species in question is Allium cepa (onion, 2n = 16), one of the most common plant indicators of environmental pollution. The working method consisted of obtaining the meristematic roots of Allium cepa and their treatment with herbicides at three different concentrations (0.5%, 1%, and 1.5%) for each herbicide for 24 h, for comparison with an untreated control. The results obtained from the cytological study indicated a strong cytotoxic and genotoxic effect for both herbicides, but especially for quizalofop-p-ethyl, where the mitotic index decreased from 30.2% (control) to 9.6% for the variant treated with 1.5% herbicide. In this case, a strong mitodepressive effect was shown by a highly significant percentage (35.4%) of chromosomal aberrations and nuclear alterations: stickiness, fragments, C-mitosis, lobulated nucleus, micronuclei, and nuclear erosion. The mitodepressive effect as well as the percentage of chromosomal aberrations increased with a higher herbicide concentration. The obtained results suggest the strong potential for pollution of the two herbicides, particularly at concentrations higher than 0.5%; therefore, we recommend caution in their use to avoid undesirable effects on the environment.
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Vencill, William K., Robert L. Nichols, Theodore M. Webster, John K. Soteres, Carol Mallory-Smith, Nilda R. Burgos, William G. Johnson y Marilyn R. McClelland. "Herbicide Resistance: Toward an Understanding of Resistance Development and the Impact of Herbicide-Resistant Crops". Weed Science 60, SP1 (2012): 2–30. http://dx.doi.org/10.1614/ws-d-11-00206.1.
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Development of herbicide-resistant crops has resulted in significant changes to agronomic practices, one of which is the adoption of effective, simple, low-risk, crop-production systems with less dependency on tillage and lower energy requirements. Overall, the changes have had a positive environmental effect by reducing soil erosion, the fuel use for tillage, and the number of herbicides with groundwater advisories as well as a slight reduction in the overall environmental impact quotient of herbicide use. However, herbicides exert a high selection pressure on weed populations, and density and diversity of weed communities change over time in response to herbicides and other control practices imposed on them. Repeated and intensive use of herbicides with the same mechanisms of action (MOA; the mechanism in the plant that the herbicide detrimentally affects so that the plant succumbs to the herbicide; e.g., inhibition of an enzyme that is vital to plant growth or the inability of a plant to metabolize the herbicide before it has done damage) can rapidly select for shifts to tolerant, difficult-to-control weeds and the evolution of herbicide-resistant weeds, especially in the absence of the concurrent use of herbicides with different mechanisms of action or the use of mechanical or cultural practices or both.
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Raj, Sheeja K. y Elizabeth K. Syriac. "Herbicidal effect on the bio-indicators of soil health- A review". Journal of Applied and Natural Science 9, n.º 4 (1 de diciembre de 2017): 2438–48. http://dx.doi.org/10.31018/jans.v9i4.1551.
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Soil microbial population, earth worms in soil, soil enzyme activity and organ carbon content in soil are considered as the bio indicators of soil health. They are used as indicators of soil health because of their active role in soil organic matter production, decomposition of xenobiotics and cycling of nutrients, ease of measurement and rapid response to changes in management practices. The assessment of soil health can be used to develop more sustainable crop production system. A number of herbicides have been introduced as pre and post emergence weed killer. The impact of herbicides on soil health depends on the soil type, type and concentration of herbicide used, sensitivity to non-target organisms and environmental conditions. The review elaborates the impact of herbicidal application on the biological indicators of soil health.
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Loux, Mark M., Anthony F. Dobbels, William G. Johnson y Bryan G. Young. "Effect of Residual Herbicide and Postemergence Application Timing on Weed Control and Yield in Glyphosate-Resistant Corn". Weed Technology 25, n.º 1 (marzo de 2011): 19–24. http://dx.doi.org/10.1614/wt-d-10-00052.1.
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Field studies were conducted in 2007 and 2008 at seven sites in Ohio, Indiana, and Illinois to determine the effect of PRE herbicide and POST application timing on weed control and yield of glyphosate-resistant corn. Levels of PRE herbicide included none; low—atrazine; medium—atrazine and metolachlor; and high—atrazine, mesotrione, and metolachlor. Glyphosate was applied POST when corn was 30 cm tall, or 1 or 2 wk later. Common lambsquarters, giant foxtail, and giant ragweed infested at least six of the seven sites, and other weed species occurred at two to three sites. Control of weeds at the time of POST application ranged from 48 to 91%, 58 to 99%, and 87 to 100% for the low, medium, and high levels of PRE herbicide, respectively, averaged over POST application timing. Control of giant foxtail and redroot pigweed decreased by about 20% between the second and third POST timing, averaged over PRE herbicide, but control of other weeds was similar among timings. Late-season control of common ragweed, velvetleaf, common lambsquarters, and Pennsylvania smartweed exceeded 90%, regardless of PRE herbicide or POST timing. Control of redroot pigweed, ivyleaf morningglory, and giant ragweed was as low as 74, 67, and 83%, respectively, but the high level of PRE herbicide resulted in 90 to 97% control of these weeds. An interaction between PRE herbicide and POST timing for late-season control of giant foxtail, tall waterhemp, and yellow nutsedge reflected the more effective control among POST timings from the higher levels of PRE herbicide. The overall trend in this study was for more effective weed control in PRE/POST herbicide programs with more comprehensive PRE herbicides that have substantial activity on both grass and broadleaf weeds. Highest yield occurred where the PRE treatment consisted of a two- or three-way combination of herbicides applied at 50% of the recommended rate or higher. Yield was reduced at all POST timings with atrazine alone or in the absence of PRE herbicide.