Littérature scientifique sur le sujet « Herbicides (terbuthylazine, linuron, simazine) »

Field studies were conducted over 3 yr to investigate the effect of chemicals on field beans density and weed control. Predominant weed species were common lambsquarters, fumitory, henbit, corn poppy, prostrate knotweed, and wild mustard. All herbicide treatments except linuron injured field beans. Mean field beans survival at harvest was 78% in alachlor and 84% in alachlor containing treatments. Only 5% survived atrazine at 1.9 kg ai ha−1. Ethalfluralin, pendimethalin, simazine, terbutylazine plus terbutryn, and trifluralin treatments produced plant survival values of 56, 82, 86, 74, and 71%, respectively. Chemical control of the main weed species overshadowed the detrimental effect on field beans density, and thus most herbicide treatments except alachlor resulted in increased dry beans yield. The best overall results occurred with linuron, simazine, terbuthylazine plus terbutryn, and pendimethalin which increased dry beans yields 76, 63, 56, and 40%, respectively, over the control plots. Common lambsquarters was the dominant weed, and prostrate knotweed and corn poppy were the most difficult and the easiest species to control, respectively.

Poa annua is a cosmopolitan, cool-season grass species regarded as one of the most significant weeds of turfgrass. It is mainly controlled by herbicides; however, repeated use of herbicides in golf turf has resulted in the evolution of multiple-herbicide resistant P. annua. Four field experiments were performed in autumn and spring in golf turf to identify effective herbicide options to control multiple herbicide-resistant P. annua. In herbicide resistance screening, the trial site population (SA1) was found to be susceptible to amicarbazone and terbuthylazine, but resistant to simazine and metribuzin at the field rate of each herbicide. Consistent with the results of the pot study, the PSII-inhibiting herbicides amicarbazone and terbuthylazine provided the best control (80–100%) of P. annua in both autumn and spring trials with minimal damage to the turf. In contrast, the other two PSII-inhibiting herbicides, metribuzin and simazine, were relatively ineffective in controlling P. annua in the field. Indaziflam also performed well in both autumn trials and reduced P. annua occurrence by >75%. Pyroxasulfone and s-metolachlor only provided moderate weed control in both the autumn and spring trials, reducing P. annua occurrence by 50%. Among the nine different herbicides, amicarbazone and terbuthylazine were found to be most effective for spring and autumn application in turf. As resistance to some PSII-inhibiting herbicides has already evolved in this field population, the use of amicarbazone and terbuthylazine needs to be integrated with other herbicide modes of action and non-chemical tactics to delay the onset of resistance to them.

AbstractThe triazine-based herbicides removal from aqueous solution on specific polymeric adsorbent was studied. Poly(divinylbenzene) modified with maleic anhydride in Diels-Alder reaction was selected for the sorption experiments because molecular structures of triazine derived herbicides exhibit complementarity to the arrangement of functional groups in the polymer. The presence of carboxyl groups in adsorbent structure resulted in specific directional interactions, such as hydrogen bonds, which can intensify adsorption ability towards triazines. In the case of both atrazine and terbuthylazine the effect is more intensive, whereas in sorption of simazine and propazine the non-specific interactions have higher importance than hydrogen bonds. Specific interactions in investigated systems are between the hydrogen atom of the amino group of triazine and the carbonyl oxygen atom of the carboxyl group of the modified poly(divinylbenzene) (O…H–N). Only in the case of terbuthylazine the creation of hydrogen bonds between hydroxyl hydrogen atom of carboxylic group and nitrogen atom containing free electron pair from triazine (O–H…N) was observed. The sorption of simazine, atrazine and propazine does not depend on pH in the acidic region, whereas in the case of terbuthylazine an increase in sorption efficiency is observed while pH decreases.

The effect of herbicides Afalon (linuron), CIPC, Gramoxone (paraquat), Krezamon (DNOC), Pielik (2,4-D • Na), Simazin (simazine) on photosynthesis of <i>Spirodela polyrrhiza (Lemnaceae)</i> was investigated with infra-red gas analyzer Infralyt III. Herbicides: Afalon, Gramoxone, Simazine inhibited photosynthesis, proportionally to used herbicide concentration. Krezamon inhibited CO₂ exchange directly after application, but later on photosynthesis increased. 2,4-D • Na and CIPC have no effect on photosynthesis even in higher concentrations.

The influence of the herbicides Afalon (active substance Linuron). Gesatop 50 (active substance simazine), Aretit (active substance dinoseb acetate) was tested concomitantly with two NPK fertilization levels on the crude lipid content and the fatty acids composition of field bean seeds.

AbstractWeed control in corn traditionally has relied on atrazine as a foundational tool to control problematic weeds. However, the recent discovery of atrazine in aquifers and other water sources increases the likelihood of more strict restrictions on its use. Field-based research trials to find atrazine alternatives were conducted in 2017 and 2018 in Fayetteville, AR, by testing the tolerance of corn to PRE and POST applications of different photosystem II (PSII) inhibitors alone or in combination with mesotrione or S-metolachlor. All experiments were designed as a two-factor factorial, randomized complete block, with the two factors being (1) PSII-inhibiting herbicide and (2) the herbicide added to create the mixture. The PSII-inhibiting herbicides were prometryn, ametryn, simazine, fluometuron, metribuzin, linuron, diuron, atrazine, and propazine. The second factor consisted of either no additional herbicide, S-metolachlor, or mesotrione. Treatments were applied immediately after planting in the PRE experiments and to 30-cm–tall corn for the POST experiments. For the PRE study, low levels of injury (<15%) were observed at 14 and 28 d after application and corn height was negatively affected by the PSII-inhibiting herbicide applied. PRE-applied fluometuron- and ametryn-containing treatments consistently caused injury to corn, often exceeding 5%. Because of low injury levels caused by all treatments, crop density and yield did not differ from that of the nontreated plants. For the POST study, crop injury, relative height, and relative yield were affected by PSII-inhibiting herbicide and the herbicide added. Ametryn-, diuron-, linuron-, propazine-, and prometryn-containing treatments caused at least 25% injury to corn in at least 1 site-year. All PSII-inhibiting herbicides, except metribuzin and simazine when applied alone, caused yield loss in corn when compared with atrazine alone. Diuron-, linuron-, metribuzin-, and simazine-containing treatments applied PRE and metribuzin- and simazine-containing treatments applied POST should be investigated further as atrazine replacements.

Ullucus tuberosus and Amorphophallus konjac are new root crops being evaluated for commercial development in New Zealand Eighteen herbicides were screened in glasshouse experiments for pre or postemergence use in these crops Methabenzthiazuron chlorpropham diuron and linuron were well tolerated by Ullucus when applied preemergence while dimethanamid oryzalin and simazine warrant further study All the postemergence treatments damaged Ullucus although linuron might show acceptable tolerance at a lower rate Acetochlor chlopropham dimethanamid linuron methabenzthiazuron oryzalin oxadiazon oxyfluorfen and pendimethalin were all well tolerated by Amorphophallus when applied preemergence while asulam flumetsulam and tribenuron were safely used postemergence Bromoxynil was also safe on Amorphophallus if applied before leaves emerged from the developing shoot

The adsorption and desorption of two herbicides, Linuron and Simazine, on a clay soil have been studied in mixtures of methanol and water. Adsorption of the herbicides decreased with increasing methanol content of the solution. An inverse log-linear relationship between the Freundlich adsorption coefficients for the two herbicides and the concentration of methanol was found. Adsorption of the herbicides in the presence of methanol followed the solvophobic theory, which describes the adsorption of hydrophobic organic compounds in soils. Values of the Freundlich adsorption coefficient for aqueous solutions, of the two herbicides extrapolated from adsorption data for the methanol/water mixtures, showed close agreement with those obtained experimentally. Hence, adsorption in aqueous solutions for pesticides of low aqueous solubility can readily be predicted on this basis. Hysteresis, observed after desorption in CaCl2 solution, decreased with increasing methanol contents for both herbicides. The decrease in hysteresis was ascribed to the swelling of the organic matter and the accompanying increased accessibility to solutes. The study showed that the presence of an organic solvent significantly affected not only the adsorption but also the desorption of herbicides in soils.

Weed control was investigated in yacon (Smallanthus sonchifolius Asteraceae) a herbaceous perennial that produces edible tubers Eight preemergence (alachlor acetochlor simazine diuron pendamethalin dimethanamid methabenzthiazuron and metribuzin) and two postemergence (linuron and methabenzthiazuron) herbicides were evaluated in field trials at Pukekohe All preemergence herbicides except metribuzin were tolerated by yacon but the best weed control was achieved with acetochlor metribuzin and dimethanamid Weeds in the untreated control caused a 62 reduction (Plt;005) in root weight relative to acetochlor alachlor metribuzin and dimethanamid The postemergence herbicides were both phytotoxic to yacon top growth but the plants subsequently recovered and plant crown production at harvest was not reduced relative to the control (P>005)

AbstractAtrazine offers growers a reliable option to control a broad spectrum of weeds in grain sorghum production systems when applied PRE or POST. However, because of the extensive use of atrazine in grain sorghum and corn, it has been found in groundwater in the United States. Given this issue, field experiments were conducted in 2017 and 2018 in Fayetteville and Marianna, Arkansas, to explore the tolerance of grain sorghum to applications of assorted photosystem II (PSII)-inhibiting herbicides in combination with S-metolachlor (PRE and POST) or mesotrione (POST only) as atrazine replacements. All experiments were designed as a factorial, randomized complete block; the two factors were (1) PSII herbicide and (2) the herbicide added to create the mixture. The PSII herbicides were prometryn, ametryn, simazine, fluometuron, metribuzin, linuron, diuron, atrazine, and propazine. The second factor consisted of either no additional herbicide, S-metolachlor, or mesotrione; however, mesotrione was excluded in the PRE experiments. Crop injury estimates, height, and yield data were collected or calculated in both studies. In the PRE study, injury was less than 10% for all treatments except those containing simazine, which caused 11% injury 28 d after application (DAA). Averaged over PSII herbicide, S-metolachlor–containing treatments caused 7% injury at 14 and 28 DAA. Grain sorghum in atrazine-containing treatments yielded 97% of the nontreated. Grain sorghum receiving other herbicide treatments had significant yield loss due to crop injury, compared with atrazine-containing treatments. In the POST study, ametryn- and prometryn-containing treatments were more injurious than all other treatments 14 DAA. Grain sorghum yield in all POST treatments was comparable to atrazine, except prometryn plus mesotrione, which was 65% of the nontreated. More herbicides should be evaluated to find a comparable fit to atrazine when applied PRE in grain sorghum. However, when applied POST, diuron, fluometuron, linuron, metribuzin, propazine, and simazine have some potential to replace atrazine in terms of crop tolerance and should be further tested as part of a weed control program across a greater range of environments.

Studying soil and water ecosystems using a microbial ecology approach, which analyses the diversity and functioning of microbial communities, can help in evaluating the impact of environmental stressors, such as xenobiotics. In fact, soil and water microorganisms play an important role in maintaining ecosystem environmental quality. For instance, the ability of soil and water to recover from chemical contamination is primarily dependent on the presence of a microbial community with the ability to remove it. Furthermore the microbial community characteristics of an ecosystem can indicate changes in resource availability and the presence of pollution. In this way, the microbial community represents an important key to understanding the impacts of environmental and anthropogenic factors on ecosystems. This thesis focuses on two groups of xenobiotics frequently detected in soil and water: pesticides and pharmaceuticals. The effects of s-triazine and phenylurea herbicides (terbuthylazine, simazine and linuron) and pharmaceuticals (such as the antiviral drug Tamiflu and two macrolide antibiotics, erythromycin and josamycin) on microbial communities in soil, surface and groundwater were studied. The researches was carried out utilizing innovative molecular techniques in order to identify the natural microbial populations involved in the chemical degradation and evaluate the direct and indirect effects of the herbicides and pharmaceuticals on the microbial community structure and functioning. For this purpose several investigations involving the selected chemicals in soil and water ecosystems were carried out: - Research activity regarding s-triazine groundwater contamination caused by diffuse sources. Although the groundwater was considered to have been without life for a long period and unable to recover from herbicide contamination, the experiments performed showed the presence of an autochthonous bacterial community able to degrade the herbicide terbuthylazine. Moreover some bacterial strains such as Janthinobacterium lividum, Advenella incenata and Rhodococcus wratislaviensis, with the capability of growing on various s-triazines were isolated. Among the three isolates, Rhodococcus wratislaviensis was also capable of mineralising the triazine-ring. Finally, an oligonucleotide probe was designed to detect this strain in soil and water samples by applying the in situ fluorescence hybridization technique. This probe can be very useful for monitoring the presence of active R. wratislaviensis populations with the potential to degrade s-triazines in contaminated aquifers and agricultural soils. The research activity was accomplished thanks to active cooperation between IRSA-CNR in Rome and Madrid Complutense University. - Research activity regarding soil herbicide contamination caused by point sources. The experiments aimed at evaluating the effects of the co-presence of herbicides (linuron and terbuthylazine) and wood amendments on soil bacterial communities. These amendments have recently been proposed for their adsorption capacity, which prevents the mobility of pesticides caused by point sources of contamination. The herbicide degradation and the microbial activity in the presence/absence of pine and oak amendments were assessed and compared. The amendments did not negatively affect bacterial community functioning in terms of dehydrogenase activity. The use of wood amendments can thus be effective in limiting the mobility of herbicides in soils. However the capacity of pine-amended soils to adsorb linuron and terbuthylazine was so high that it hampered herbicide degradation and this should be taken into account since it can modify the persistence of these herbicides. This research was performed by IRSA-CNR together with Spanish CSIC. - Research on the assessment of the effects of pharmaceutical waste disposal on bacterial communities in soil and groundwater. The research regarded an open quarry contaminated by pharmaceutical residuals (erythromycin and josamycin) owing to its previous improper use for disposal of pharmaceutical waste by a factory producing macrolide antibiotics. The microbiological community characteristics (bacterial abundance, diversity, viability and activity), proposed as microbial indicators, together with chemical investigations of soil and groundwater samples, made it possible to evaluate the quality state of the site. - Research on the effects of the antiviral drug Tamiflu (recommended for the treatment of cases of avian and swine influenza) on the bacterial community of a surface ecosystem. The role of the bacterial community in the antiviral degradation was demonstrated in microcosm experiments and some bacterial groups, analyzed by fluorescence in situ hybridization, were found to increase in number when there was a halving of the pharmaceutical. This research was performed by IRSA-CNR together with Bologna University. - Research on variations in bacterial community structure in soil, surface water and groundwater in the presence of herbicides (terbuthylazine, simazine and linuron) or pharmaceuticals (Tamiflu). The research shows that fluorescence in situ hybridization was a useful tool for following the dynamics of individual microbial populations in the ecosystems considered and highlighted the presence of particular groups presumably involved in chemical degradation.