Systemic Herbicide Research Articles

Organo-Mineral Interactions Involved in Herbicide Sorption on Soil Amended with Peats of Different Maturity Degree

The sorption of three herbicides (alachlor, atrazine and linuron) on samples from six peats of progressive degree of maturity (fibric, hemic or sapric types) and soil samples (dryland agricultural Calcic Luvisol amended with the peats) was determined. The extent of the sorption was examined in terms of peat maturity (up to 220 analytical descriptors of the peat material). In most cases, a sorption enhancement effect was observed in the peat–soil system compared with the sum of the sorption in peat and soil alone, i.e., a positive interaction leading to an increase in soil matrix reactive sites. The analytical characteristics of humic and bitumen peat subfractions were useful in forecasting sorption performance. This was the case for high molecular weight hydrophobic fractions, the extent of the alkyl domain in humic substances and oxygen-containing groups. Correspondence analysis illustrated how different characteristics of the peats played a distinct role in sorption in the herbicide–peat system or in the soil–peat–herbicide system. In the former system, there was a relevant bearing of parameters indicating low peat maturity, whereas in the second the sorption was mainly explained by peat colloidal properties, including the concentration and base saturation of oxygen-containing functional groups.

Resposta de glyphosate em mucuna-preta desenvolvida em diferentes temperaturas

A mucuna-preta é uma leguminosa anual, que nos últimos anos assumiu posição de destaque como uma importante planta daninha em várias regiões. O controle químico constitui-se umas das principais ferramentas de manejo de plantas daninhas, contudo, diferentes condições climáticas podem influenciar consideravelmente a eficácia de muitas moléculas. O glyphosate é um dos herbicidas sistêmicos, de amplo espectro de controle, amplamente utilizado para o controle químico de plantas daninhas. Dessa forma, o objetivo desse trabalho foi avaliar as respostas de crescimento de plantas de mucuna-preta em diferentes temperaturas submetidas a doses de glyphosate. Foram realizados dois experimentos, em casa de vegetação, em delineamento inteiramente casualizado, com cinco repetições. Os tratamentos foram constituídos por nove doses de glyphosate (g ha-1 e.a.): 2,81; 5,62; 11,25; 22,5; 45,0; 90,0; 180,0; 360,0 e 720,0, além de um tratamento controle (sem aplicação de herbicida). Foram realizadas avaliações visuais de fitointoxicação aos 7, 14, 21 e 28 dias após a aplicação (DAA), e aos 28 DAA massa seca da parte aérea das plantas, além da extração e quantificação da cera epicuticular. Doses de glyphosate inferiores a 22,5 g ha-1 e.a. não ocasionaram nenhum efeito nas plantas e nas doses superiores a 360 g ha-1 e.a. proporcionou a morte da mucuna-preta em ambos os experimentos. A resposta da mucuna-preta nas doses intermediárias de glyphosate variou e associou-se as diferentes condições de temperatura que provocaram diferenças nas quantidades de ceras nos experimentos realizados. As plantas de mucuna-preta respondem de maneira diferente ao herbicida glyphosate em condições de temperatura diferente.

Glyphosate-remediation potential of selected plant species in artificial wetlands

Glyphosate is a systemic herbicide with an important environmental impact due to its adverse effect on non-target organisms. Its removal can be accomplished by wild (native) plants which, together with their associated microbiota, have acquired tolerance against glyphosate or are able to degrade it. Little is known, however, about these plants' potential for glyphosate remediation and the role that plant-microbe interactions play in this process. The objective of the present study was to evaluate plant species from locations with a history of glyphosate exposure – drainage ditches of banana plantations (Musa sp.), or riparian areas - to determine which, in combination with their microbiota, promote the removal of glyphosate. Five plant species were selected to evaluate their response to inundated growing conditions and exposure to 20 mg glyphosate acid equivalent/L for 47 days. Parameters affecting plant growth and glyphosate removal were recorded. Rhizosphere bacterial strains were identified and their tolerance to different glyphosate concentrations determined. Also, the activity of 19 rhizospheric enzymes associated with the phosphorus, carbon and nitrogen cycles were analyzed. Glyphosate-treated Panicum maximum exhibited the highest removal efficiency (87%), followed by Typha domingensis and Heliconia latispatha. All plants were associated with glyphosate-tolerant bacteria, and in the cases of Xanthosoma sagittifolium and Fimbristylis dichotoma, strains were recovered that even succeeded in growing in a medium containing 40 g glyphosate ae/L. Processes involved in carbon, nitrogen and phosphorus metabolism in the rhizosphere were affected by glyphosate exposure, and the importance of plant-microbe-substrate interactions in the elimination of glyphosate was evinced. Although all plants contributed to the removal of glyphosate, their use in phytoremediation projects will depend on the location and nature of the environmental problem to be resolved.

Do applications of systemic herbicides when green fruit are present prevent seed production or viability of garlic mustard (Alliaria petiolata)?

AbstractGarlic mustard [Alliaria petiolata (M. Bieb.) Cavara & Grande] is a biennial invasive plant commonly found in the northeastern and midwestern United States. Although it is not recommended to apply herbicides after flowering, land managers frequently desire to conduct management during this timing. We applied glyphosate and triclopyr (3% v/v and 1% v/v using 31.8% and 39.8% acid equivalent formulations, respectively) POST to established, second-year A. petiolata populations at three locations when petals were dehiscing and evaluated control, seed production, and seed viability. POST glyphosate applications at this timing provided 100% control of A. petiolata by 4 wk after treatment at all locations, whereas triclopyr efficacy was variable, providing 38% to 62% control. Seed production was only reduced at one location, with similar results regardless of treatment. Percent seed viability was also reduced, and when combined with reductions in seed production, resulted in a 71% to 99% reduction in number of viable seeds produced per plant regardless of treatment. While applications did not eliminate viable seed production, our findings indicate that glyphosate and triclopyr applied while petals are dehiscing is a viable alternative to cutting or hand pulling at this timing, as it substantially decreased viable A. petiolata seed production.

Establishing targeted control of creeping perennial weeds with soil‐active chemical injections: Assessment of subterranean bud responses in contact

AbstractIncreased infestation of aggressive creeping perennial weeds is a significant problem in urban vegetation management programs. These weeds produce vigorous biomass and extensive underground networks of either rhizomes or creeping roots that easily regrow from numerous buds. Foliar application of proper systemic herbicides has been a most effective way to suppress regrowth from underground creeping organs; however, killing the mature plants has disadvantages from aesthetic, economic, and ecological viewpoints. Therefore, we intended to test the possibility of soil‐injection of soil‐active herbicides for effective control of the perennial weeds which develop underground network systems. A pot experiment using combinations of seven species (seven rhizomatous and two having creeping roots) and five chemicals (four herbicides and a plant growth regulator) was conducted to assess whether and how chemicals diffused in soil affect the sprout and growth of buds on creeping organs. All the tested herbicides completely inhibited bud sprouting in one and more species when applied at median or high rates, while most of the flurprimidol‐applied segments sprouted but shoot elongation was significantly reduced. Characteristics of each herbicide were also reflected in the selectivity and features of new outgrowth. The results indicated that chemicals existing in soil were undoubtedly absorbed and affected bud activities. It is concluded that soil injection that delivers the probable soil‐active chemicals to subterranean creeping systems could be a promising technology for controlling noxious creeping perennials.

Growth performance and reproductive function impairment of glyphosate-based herbicide in male guinea pig (Cavia porcellus).

Glyphosate formulations, widely applied non‐selective systemic herbicides, are progressively becoming the most controversial pesticides on the market due the adverse effects they pose to humans and environment. The information on these potential hazardous effects to the handlers of the pesticide remains obscure. This study investigated effects of glyphosate‐based herbicide on growth performance, seminal parameters and hemato‐biochemical profiles in male guinea pig. Forty sexually mature male guinea pigs weighing between 393.3 and 418.4 g were divided into four groups of 10 animals each and orally administered 0, 186, 280 and 560 mg/kg body weight of WILLOSATE daily for 60 days. Daily feed intake and body weight gain were recorded. At the end of experimental period all animals were humanely sacrificed, and blood samples and vital organs were collected for appropriate analysis. Results showed a significant decrease (p < 0.05) in body weight gain (−102.2%), final body weight (−9.8%) and feed intake (−13.1%) of animals following sub‐chronic exposure of WILLOSATE. The weights of the liver and kidney increased significantly (p < 0.05) by 25.4% and 28.8%, respectively, while testicular weights decreased (p < 0.05) by 24% with increasing doses of WILLOSATE. A decrease in sperm motility (−67.9%), viability (−52.7%) and concentration per vas deferens (−40.7%), and an increase in sperm major (28.1%) and minor (45.3%) morphological aberrations were recorded in WILLOSATE – exposed guinea pigs when compared to controls. There was a dose‐dependent increase (p < 0.05) in MCV and WBC and a decrease in Hb content and RBC, as well as serum content in total protein (−11.8%). The serum content of cholesterol (37.8%), urea (87.1%), creatinine (22.4%), ALAT (74.2%) and ASAT (88.7%) were significantly higher in treated groups compared to controls. These results point toward the toxic effects of WILLOSATE on vital organs and reproductive function of the body at high doses and long‐term exposure.

Confusing Ions on Purpose: How Many Parent Acid Molecules Can Be Incorporated in a Herbicidal Ionic Liquid?

To expand the application range of herbicidal ionic liquids (HILs), we attempted to increase the amount of the systemic herbicide dicamba in its HILs through the formation of neither purely ionic n...

Source-sink relationships of wheat plants obtained by the application of systemic herbicides

Abstract: The objective of this work was to evaluate the potential of solute translocation among stems of wheat (Triticum aestivum), by the application of the systemic herbicides clethodim and glyphosate. The experiments were carried out in greenhouse conditions, using wheat cultivars with contrasting potential for tillering, during the winter of 2017 and 2018 in Southern Brazil. Clethodim was applied on isolated stems, to evaluate the potential translocation of solutes from the first three tillers. Translocation was evaluated by the yield parameters on stem ears not treated with clethodim. Glyphosate was used to evaluate the potential translocation of solutes from late tillers. Translocation was evaluated by the assimilation of carbon in stems without the glyphosate treatment. When applied on isolated primary tillers, clethodim reduced yield parameters only in treated stems, which shows that the assimilates were targeting the main sink, in detriment of the other organs. There was a decrease in net carbon assimilation in stems without the glyphosate treatment at the first visible node stage. Glyphosate applied on late tillers, at anthesis, reduced even more net carbon assimilation in nontreated stems of the primary tillers of the BRS Parrudo wheat cultivar (low tillering). Well-developed late tillers show higher potential of solute translocation to the whole plant than the poor-developed ones.

Acute Toxicity (LC50) Of Cyhalofop Butyl on Gambusia Holbrooki

Cyhalofob butyl is a synthetic herbist. This herbicide is a systemic herbicide and is used in weed control especially on celtic agriculture. In this study, the acute toxicity (LC50) of this herbist (Chillinger 200 EC 200, cyhalofob butyl) was investigated, which is currently used intensely in the fight against herbists in Thrace region, including Cyhalofob butyl. Acute toxicity (LC50 value) for this herbicide has been investigated in the common mosquito fish (Gambusia holbrooki) in Thrace Region. Lethal Dose 50 experiments were performed in 3 replicates in static test runs (water temperature 27.70 ±0.56 C, water pH 8.88± 0.37, and conductivity 718.25±21.113 µhos). The experiment results obtained for Chillinger 200 ec during the experiments were evaluated by Trimmed Spearman–Karber method. 96-hour LC50 value for the mosquito fish Gambusia holbrooki was calculated as 4.140 ppm.

INFLUENCE OF TIME OF GLYPHOSATE APPLICATION IN THE CONTROL OF BRACHIARIA

The no-tillage system is considered an important tool for sustainable production. In this system, the burndown of brachiaria is usually performed with the application of systemic herbicides, such as glyphosate. As a result of environmental conditions (temperature, relative humidity and winds), the timing of spraying can directly interfere in the control efficiency. Therefore, the objective was to study different times of application of glyphosate in the control efficiency of Urochloa brizantha cv. Marandu. The glyphosate was applied in the morning, afternoon and evening, at doses of 0; 360; 720; 1080; 1440 and 2160 g a.e. ha-1. To analyse the efficiency of U. brizantha burndown, the phytotoxicity was evaluated at 21 days after application. At 42 after application a mowing was done and 90 days after mowing, the dry matter accumulation and the Leaf Area Index of regrowth were determined. The best control results of Urochloa brizantha cv. Marandu were obtained in the applications of glyphosate during the morning and afternoon. Evening applications of glyphosate should be avoided.

Effect of Method and Time of Management on European Buckthorn (Rhamnus cathartica L.) Growth and Development in Minnesota

European buckthorn is an exotic problematic invasive woody species that has displaced native plant species in Minnesota woodlands. Buckthorn is also an overwintering host for oat crown rust and soybean aphids, which can cause significant crop yield losses. The overall goal of this study was to test multiple buckthorn control methods and examine the establishment of native plant species in colonized areas. Specific objectives were to 1) determine the effectiveness of buckthorn control methods when applied in different seasons, 2) monitor seedling recruitment and resprouting ability of buckthorn saplings following treatment, 3) monitor recruitment and survival of native plant species following treatment, and 4) characterize buckthorn carbohydrate fluctuations and considerations for timely and effective buckthorn management. Field experiments conducted for two years in two locations (Eagle Lake Regional Park and Battle Creek Regional Park, Minnesota, U.S.A), tested four buckthorn control treatments: 1) cutting only; 2) cutting+stump treatment with herbicide (triclopyr); 3) cutting+stump treatment with herbicide+burning, and 4) cutting+burning. Untreated controls were included in each experiment. Across management seasons, the cutting+stump treatment with herbicide resulted in higher seedling densities for buckthorn and other species the next season compared to cutting only without herbicide application. Spring management resulted in the lowest seedling density the next season for both buckthorn and other plant species, and spring control treatments that included herbicide and burning resulted in higher buckthorn and native species seedling densities than treatments without burning. Because seasonal total nonstructural carbohydrate levels in buckthorn crowns were highest in the fall season, we recommend applying systemic herbicides in the fall when carbohydrates are translocated for storage to facilitate herbicide translocation and efficacy. Our study shows that integrating multiple buckthorn control methods reduces buckthorn populations and increases native species diversity. For long-term control of buckthorn seedling establishment, follow-up treatments like applying foliar herbicide sprays can be used in addition to prescribed burning.

Photocatalytic Degradation of a Systemic Herbicide: Picloram from Aqueous Solution Using Titanium Oxide (TiO2) under Sunlight

The photocatalytic degradation of picloram (4-amino-3,5,6-trichloro-2-pyridincarboxylic acid), which is one of popular acidic herbicide, was investigated with the existence of titanium oxide (TiO2) under sunlight. The total photocatalytic degradation of 20 ppm of picloram was occurred within 30 min irradiation with TiO2, while a negligible degradation was found without TiO2 under sunlight. The influence of various parameters, like TiO2 dosage, solution initial pH, intensity of light, reaction temperature and irradiation time, was found during the photocatalytic degradation of picloram. The mineralization of picloram was proved by the deterioration of total organic carbon (TOC) of the photocatalytic process. The pseudo–first order kinetics of photocatalytic degradation was obtained according to the Langmuir–Hinshelwood model, and the reaction rate constant was 17.6 × 10−2 min−1. Chloride ion, ammonium ion, nitrate ion and CO2 were erected as the final products after completing the photocatalytic degradation of picloram. The intermediate products could not be determined by the GC–MS during the degradation of picloram. Therefore, the degradation mechanism of the picloram was proposed based on the frontier electron density and the point charge at each atom of the picloram molecule. The photocatalytic degradation method, using sunlight, may develop into as a pragmatic technique to purify picloram contaminated wastewater.

Integrated Weed Management in High Density Fruit Orchards

Despite the productivity, achieving long-term sustainability and maintaining plant biodiversity have become the pivotal goals in orchard floor management, especially along tree rows. Thus, the paradigm of eradicating weeds in the tree row using chemical herbicide or repeated soil tillage needs to be substituted with more sustainable alternatives. This study was conducted in two commercial apple and peach orchards in Marche region (Italy). Two integrated mechanical approaches, integrated mowing (mower and brush or disc) and integrated tillage (blade weeder and integrated mowing), were compared with the standard herbicide system in a 2-year trial. Weed species diversity, soil coverage, and weed biomass production, including, gas exchange parameters, trunk cross-sectional area (TCSA), fruit yield and quality were measured. Overall, both integrated practices demonstrated approximately 82%, 91% and 113% more species diversity, soil coverage, and weed biomass production, respectively, than herbicide systems. No significant differences were found in terms of tree gas exchange parameters, growth and fruit yield. However, a few fruit quality parameters such as fruit firmness, soluble solids content (SSC) and dry matter content responded positively to the integrated practices. These results suggest that the integrated mechanical approaches of weed management increased orchard biodiversity, and had no adverse effects on tree growth, fruit yield, and quality. The average costs per hectare associated with chemical weed control were 66.5% and 72% lower, respectively, compared to integrated tillage and integrated mowing. However, the government subsidies provided to the orchardists to encourage sustainable management practices were able to offset such additional costs.

The Potential of Spectral Measurements for Identifying Glyphosate Application to Agricultural Fields

Glyphosate is one of the most widely used non-selective systemic herbicides, but nowadays its application is controversially discussed. Optical remote sensing techniques might provide a sufficient tool for monitoring glyphosate use. In order to investigate the potential of this technology, a laboratory experiment was set-up using pots with rolled grass sods. Glyphosate-treated plants were compared to drought-stressed and control plants. All pots were frequently measured using a field spectrometer and a hyperspectral-imaging camera. Plant samples were analysed for photosynthetic pigments, polyphenols and dry matter content. Eight selected vegetation indices were calculated from the spectral measurements. The results show that photosynthetic pigments were sensitive to differentiate between control and glyphosate treated plants already 2 days after application. From the vegetation indices, the normalized difference lignin index (NDLI) responded most sensitively followed by indices referring to photosynthetic pigments, namely, the carotenoid reflectance index (CRI-1) and the photochemical reflectance index (PRI). It can be concluded that spectral vegetation indices are, in principal, a suitable proxy to non-destructively monitor glyphosate application on agricultural fields. Further research is needed to verify its applicability under field conditions. An operational monitoring is, however, currently limited by the requirements for temporal and spectral resolution of the satellite sensors.

Gamma ray irradiation assisted decomposition for isoproturon pesticide in aqueous solutions: A detailed study

Isoproturon (IP), a systemic herbicide, is also considered as a potential groundwater contaminant. In the present study, the radiation-induced degradation of IP employing gamma-rays is investigated. Several factors such as radiation dose, pH and the presence of co-contaminants such as H2O2, isopropanol, tert-butanol, coffee waste (CW), carbonized coffee waste (CWC) and TiO2, which might affect the degradation process are examined. The IP concentration decreased with the increase of radiation dose and the degradation obtained at pH = 7.0 is found to be 90%. The degradation efficiency decreases with the increase of initial concentration at the same radiation dose. Co-contaminants such as H2O2, TiO2 and CW had increased the degradation efficiency. The process followed by first order reaction kinetics. Furthermore, the increase of the concentration of H2O2, isopropanol, tert-butanol and the weight of TiO2, CW and CWC resulted in the decrease of the degradation values. The pH value was found to effect the removal efficiency and the degradation process was enhanced under neutral condition. IP concentration of 30µ M was selected as standard, while 0.63 kGy was selected as the standard radiation dose.

Adsorption–desorption behavior of benzobicyclon hydrolysate in different agricultural soils in China

Benzobicyclon is a systemic herbicide that was officially registered in China in 2018. The environmental behaviors of benzobicyclon hydrolysate (BH), the main metabolite and active product of benzobicyclon, remain poorly understood in paddy fields. Here, agricultural soil samples were collected from paddy fields in Jiangxi (Ferralsols), Shandong (Alisols), Hebei (Luvisols), Heilongjiang (Phaeozems), Zhejiang (Anthrosols), Sichuan (Gleysols), Hainan (Plinthosols), and Hubei (Lixisols) across China. The equilibrium oscillation method was used to study the adsorption–desorption behaviors of BH in the eight soils. The relationships between BH adsorption and soil physicochemical properties, environmental factors (temperature and initial solution pH), and other external conditions (addition of humic acid, biochar, and metal ions) were quantified. The adsorption–desorption parameters of BH in all soils were well fitted by the Freundlich model. The adsorption constant of BH varied between 0.066 and 4.728. The BH adsorption capacity decreased in the following order: Phaeozems > Alisols > Ferralsols > Lixisols > Plinthosols > Anthrosols > Luvisols > Gleysols. The Freundlich adsorption and desorption constants of BH were linearly positively correlated with soil clay content (R2 = 0.711 and 0.709; P = 0.009 and 0.009, respectively), organic carbon content (R2 = 0.684 and 0.672; P = 0.011 and 0.013, respectively), and organic matter content (R2 = 0.698 and 0.683; P = 0.010 and 0.011, respectively); however, their linear relationships with soil cation exchange capacity were not significant (R2 = 0.192 and 0.192; P = 0.278 and 0.278, respectively). The adsorption and desorption constants of BH had negative, albeit not significant, correlations with soil pH (R2 = 0.104 and 0.100; P = 0.437 and 0.445, respectively). The adsorption of BH by soil occurred spontaneously and was mainly based on physical adsorption. Either low or high temperature reduced the ability of the soil to adsorb BH. The addition of humic acid to the soil increased BH adsorption, while the addition of biochar increased the solution pH, resulting in decreased BH adsorption. Cation type and ionic strength also had strong effects on BH adsorption. With the exception of Phaeozems, BH exhibited intermediate or high mobility in the agricultural soils and thus poses risks to surface water and groundwater.

Novel aroA of Glyphosate-Tolerant Bacterium Pseudomonas sp. Strain HA-09 Isolated from Roundup-Contaminated Garden Soils in Iran.

Background: Glyphosate is a non-selective systemic herbicide with a broad spectrum of weed control that inhibits a key enzyme, 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase, in the shikimate pathway.Objectives: Isolation and analysis of the epsps (aroA) gene responsible for glyphosate-tolerance in bacteria from Roundup- contaminated soils was the aim of this study.Materials and Methods: Sampling was done from the soil of the gardens which were heavily contaminated by Roundup herbicide and then bacterial screening was performed in the presence of high concentrations of glyphosate. The genus of bacterium was identified via molecular methods such as 16S rRNA sequencing. The aroA gene of this bacterium (aroAHA-09) was isolated using the primers designed-upon specific regions of aroA genes available in NCBI GenBank database. The PCR product was cloned, sequenced and subcloned into pET28a as an expression vector and transferred into E. coli strain BL21(DE3). The cells were inoculated in liquid M9 minimal medium containing IPTG and different concentrations of glyphosate.Results: The genus of bacterium was identified as Pseudomonas sp. strain HA-09. The isolated aroAHA-09 gene from this bacterium was approximately 2.2 kb in size. Bioassay of E. coli expressing this gene showed high tolerance to glyphosate (up to 300 mM).Conclusion: The aroAHA-09 gene could be considered as a novel and efficient candidate for development of glyphosate-tolerant crop plants.

Palatability of glyphosate in ants: a field experiment reveals broad acceptance of highly polluted solutions in a Mediterranean ant.

Glyphosate is a systemic herbicide still used in many countries, though there are several known detrimental effects on animals. Previous studies concerning its effects on social insects are available, but they are primarily focused on honeybees; little is known about the interactions of this compound with ants. Here, we assessed whether different concentrations of glyphosate can be perceived by ant workers and to what extent. As a model species, we used the Mediterranean ant Crematogaster scutellaris, commonly found in agroecosystems. We performed 3000 individual tests of acceptance using ten different solutions of various concentrations of the herbicide. Half of the solutions contained added sucrose in order to test the possible masking effect of the sugar taste on glyphosate. We used comparable glyphosate concentrations to those previously used in other studies on social insects or suggested by the producer. We found that the acceptance of the solutions decreased as the concentration of the herbicide increased. However, a significant percentage of ants drank the solutions with concentrations up to dozens of times higher than those inducing toxic effects in bees. In light of these results, we urge further assessment of the effects of glyphosate on ants, particularly because the food ingested by workers is transferred to the brood and queens, posing a potential threat to the health of the entire colony. Surprisingly, we did not record any difference in acceptance between solutions with and without sugar; this point is discussed regarding drought stress.

Southern Sandbur (Cenchrus echinatus L.) Control in Bermudagrass Pastures with Indaziflam Herbicide Systems

Field studies were conducted during 2019 growing season in north-central, south-central, and the Coastal Bend areas of Texas to evaluate indaziflam herbicide systems for southern sandbur control and Coastal bermudagrass tolerance. Indaziflam caused no bermudagrass stunting at any location when applied preemergence (PRE) at 0.04 to 0.07 kg ai ha-1. Glyphosate at 0.35 kg ae ha-1 caused bermudagrass stunting which ranged from 16 to 65% when evaluated 3 to 5 weeks after application; however, when evaluated at the end of the growing season, no bermudagrass stunting was evident when compared with the untreated check. Southern sandbur control with indaziflam, when evaluated 28 to 32 weeks after the initial indaziflam PRE application, ranged from 85 to 99% in north-central Texas, 65 to 95% in south-central Texas, and 95 to 100% in the Coastal Bend region. Southern sandbur control with pendimethalin PRE system ranged from 74 to 100%, 11 to 85%, and 100% in those regions, respectively. Indaziflam represents a safe option for forage and hay producers in Texas to control southern sandbur.

МОДЕЛИРАНЕ НА ХЕРБИЦИДНА УРЕДБА ЗА ТРЕТИРАНЕ НА НАСАЖДЕНИЯ ОТ ПРАСКОВИ

An approach to modeling herbicide installation for the treatment of peach plantations is proposed. The height of the stem was determined for 4 varieties of peaches. Considering this parameter, the maximum height of the herbicide system and the nozzles on it are indicated. Simulated modelling of the sprayed fluid along the working width of each nozzle was performed. The irregularity of spraying was determined depending on the distance between the nozzles. On the basis of the analysis, the optimal parameters of the spreader system were determined: height - 0.35 m, distance between the spreaders - 0.40 m.