Tank Mixtures Research Articles

EFFECTIVENESS OF HERBICIDES IN CORN AGROCENOSES

Maize is one of the least competitive crops with weeds in its crops, so cultivated plants can lose their productivity potential most during the initial stages of growth and development. The critical period of the impact of weeds on corn is 40–50 days, it lasts from germination to the shedding of panicles - flowering. Counting weeds on the experimental sites on average over two years of research showed that the number of grass and dicotyledonous weeds was within 159 pcs./m2. Application of Astral + Kideka herbicides at rates (0.9 l/ha + 1.1 l/ha) in the phase of 3-5 leaves of corn in combination with the biopreparation Agrinos B showed that the level of weediness, compared to the control without herbicides, decreased by 73.6% 30 days after application of the drugs, and by 99.3% during the period of corn harvesting. The number of weeds in the control plots of the experiment (without application of herbicides) for the period of corn grain harvesting was within 142 pieces/ha, and the air-dry weight was equal to 3207 g/m2, while in the areas where herbicides were applied, the air-dry weight was 19-130 g/m2. Reduction to control in the range of 96.0-99.4%. The highest rates of corn grain yield were noted in the areas where the tank mixture of Astral + Kideka herbicides was applied, at the rate of application of 0.9 l/ha + 1.1 l/ha + Agrinos B, at the rate of consumption of 1.0 l/ha in the phase of 3-5 leaves of corn. In these areas, on average, over two years of research, the yield of corn grain was within 7.03 t/ha, which is 4.79 t/ha or 213.8% more than the control areas. The use of tank mixtures of herbicides and biological preparations is an economically beneficial measure. In addition, the dose of chemical preparations is reduced, which helps to reduce the pesticide load on the environment.

The timing of oilseed flax sowing in the steppe zone of Western Siberia

In the steppe zone of the Omsk region from 2020 to 2022 two sowing periods (May, 15 and 25) of Severny oilseed flax with a seeding rate of five million germinated seeds per hectare on four chemicalization backgrounds were tested. With the norm for the steppe zone of the HTC 0.78 all the years of the experiments this indicator was only 0.37-0.58. Having sowed in the third decade of May, the yield of oilseed flax seeds with the use of a tank mixture of herbicides (Agritox, WC 1 l/ha and Legion, EC 0,4 l/ha) with a working fluid flow rate of 200 l/ha 0.868 tons of oilseeds were obtained from 1 ha and 1.009 t/ha were obtained with the help of a complex chemicalization, where Lingohumate 100 g/ha was used during the leaf development phase in a mixture of herbicides and Isagry Bor 0.5 l/ha during the building phase. They provided a profitability level of 197 %. Similar results were obtained having used only herbicides – 179.9 %. Ammophos’s introduction during sowing did not bring a significant increase in yield and reduced economic indicators. Having sowed in the second decade of May, the annual oilseeds yield was significantly lower and, accordingly, the level of profitability was decreasing sharply from 27.8 to 87.8 %.

Phytosanytary status of winter wheat crops depending on the influence of pesticide tank mixtures in the Northern Steppe of Ukraine

Phytosanytary status of winter wheat crops depending on the influence of pesticide tank mixtures in the Northern Steppe of Ukraine

Particle drift simulation from mesotrione and rimsulfuron plus thifensulfuron-methyl mixture through two nozzle types to field and vegetable crops.

Potential for off-target movements follows every herbicide application. Because the launch of acetolactate synthase (ALS)- and 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicide-tolerant crops will increase the treated area, there is a need to assess the possible negative consequences of any particle drift from those herbicides. Drift happens with every pesticide application, requiring mitigation. Various factors influence drift. Some, such as nozzle type, working pressure, and boom height, can be managed. Others, such as wind, are not easy to manage. In our study, an herbicide tank mixture of mesotrione with rimsulfuron plus thifensulfuron-methyl was sprayed in a low-speed wind tunnel to simulate drift. The airspeed was set at 4.4ms-1, representing the labeled upper limit for applications. The herbicide solution was sprayed through XR110015 and TTI110015 nozzles. Eight crops were exposed to herbicide drift treatments and biomass data were collected. Droplet size spectra and tracer depositions were evaluated. Tracer deposition was on average threefold higher in all downwind distances (0.5, 1, 2, 3, 4, 6, 9, and 12m) from the XR nozzle in comparison to the TTI nozzle. As a consequence, greater biomass reduction was recorded for applications with the XR compared to the TTI nozzle from 1 to 12m downwind. At 12-m distance, biomass was decreased by 7-78% using XR nozzle while 1-27% using the TTI nozzle. Because drift can injure crops, it is very important to mitigate drift from application of formulations containing mesotrione and rimsulfuron plus thifensulfuron-methyl in combination. This can be done by selecting the appropriate nozzle and ensuring optimal distances between crops.

Борьба с засорителем посевов масличного льна – имидазолиноноустойчивым подсолнечником

The research was conducted in 2020-2022 to find effective ways of controlling the volunteer plants of imidazolinone-resistant sunflower in oil flax sowings, providing high biological and economic efficiency, crop yield, and seed quality on leached chernozem in natural and climatic conditions of the Western Ciscaucasia. We studied methods of chemical protection of oil flax with tank mixtures of herbicide combinations: anticotyledonous contact herbicide Basagran, WS and systemic herbicide Cleo, WDG, Sekator Turbo, OD, and graminicide Zellek-super, EC. We used established methods for field agronomic experiments with oil crops. Seeds of imidazolinone-resistant sunflower hybrid were evenly sown on the experimental plot to simulate the volunteer plants. The phytotoxicity of herbicides on sunflower plants was evaluated using a 9-point EWRC scale. The tank mixtures Basagran,WS (4 l/ha) + Zellek-super, EC (1.0 l/ha) and Basagran, WS (4 l/ha) + Sekator Turbo, OD (0.1 l/ha) + Zellek-super, EC (1.0 l/ha) do not provide ef-fective control of the volunteer plants and are not recommended for use. The composition Basagran, WS (4 l/ha) + Cleo, WDG (0.12 kg/ha) + Zellek-super, EC (1.0 l/ha) provides destruction of the volunteer plants, contributing to higher yield and oil content of seeds, but it is very expensive and decreases the laboratory germinating ability of flax seeds, so it cannot be used in industrial seed production. A tank mixture of Cleo, WDG (0.12 kg/ha) + Sekator Turbo, OD (0.1 l/ha) + Zellek-super, EC (1.0 l/ha) has lower cost, provides high herbicidal effectiveness against the volunteer plants of imidazolinone-resistant sunflower, contributes to obtaining a high yield, oil content and laboratory germination of oil flax seeds and is recommended for use both in industrial seed production and in the production of commercial seeds.

SPRING WHEAT PROTECTION TECHNIQUES IN ARID CONDITIONS OF THE LOWER VOLGA REGION OF THE RUSSIAN FEDERATION

Justification. The article presents studies on the influence of the new generation of chemical and biological drugs for yield and quality of grain of spring wheat in the Nizhny Volga conditions. The object of research is the variety of spring wheat Kamyshinskaya 3, the E-lectures of the Federal Tax Service of Agroecology of the Russian Academy of Sciences (Russia, Volgograd).Studies were wrapped in the experimental field of the Federal Tax Code of the Agroecology of the Russian Academy of Sciences according to the thematic plan. It was experimentally obtained that the processing of seeds of spring wheat with a tank mixture of BSKA-32.0 l/t+ potassium humate 1.0 l/t allows you to obtain the highest yield of spring wheat grain in the conditions of the experimental field of the Federal Tax Service of the Russian Academy of Sciences – 1.34 t/ha s. profitability of 69.0%.
 The purpose of the work is to study the techniques of plant protection in adaptive systems of agriculture using the new generation chemical and biological drugs in conditions of light brown soils of the Lower Volga region.
 Materials and research methods. The soil of the experimental site is light chestnut, with low gross nitrogen, the average content of movable phosphorus and an increased metabolic content. The content of organic broadcasts in the soil reaches 1.2-2.0%, pH = 7-8. All agrotechnical measures were performed according to the set deadlines. The main soil processing was carried out in the first decade of September to a depth of 20-22 cm. Intercession harrowing in two traces and pre-sow cultivation (spring). Sitting was carried out in early April, as the physical ripeness of the soil occurs, the norm of sowing 3.5 million pcs. seeds per 1 ha, Szhelka SZ 3.6. Phytosanitary inspection of plants was carried out in a way of the work program and the NIIR methodology in accordance with the recommendations [12].
 Results. Processing of seeds with inshur perform, CS 0.5 l/t + biogumatekoss 0.25 l/t and BSKA-32.0 l/t + potassium humate 1.0 l/tmicated to increase the germination of seeds by 7% compared to with a control sample. The use of BSKA-3 2.0 l/t+ potassium humate 1.0 l/t decreased the amount of root rot to 16.5 % (control-21.6 %). Studies revealed the effectiveness of the use of Inshur Permor, CS 0.5 l/t + biogumatekoss 0.25 l/t and BSKA-32.0 l/t + potassium humate 1.0 l/t in an increase in yield indicators of 1.5 times. The same options turned out to be the most profitable in comparison with other prototypes.
 Conclusion. The results of the studies indicate that during the production of spring wheat, the use of a bio-guum in a mixture with chemical retirers allows you to create optimal conditions for the growth and development of this culture. Scientific research has established that the use of a chemical retirement with biological products is a reserve to increase the biological and economic efficiency of the use of plant protection products, increasing the profitability of grain production.

Effectiveness of using the mixtures of herbicides flumioxazine and fluorochloridone in sunflower crops

Aim. This work is devoted to the search for potential partners for the integrated application of flumioxazine in sunflower crops. This herbicide is an inhibitor of protoporphyrinogen oxidase (PPO) in weed plants. The resistance to this class of herbicides is not yet common today, compared to other classes. Therefore, the work is aimed at de- veloping flumioxazine-based herbicide compositions that effectively prevent the emergence of herbicide-resistant weed biotypes. Methods. The interaction effects, weed control efficiency, and crop selectivity were studied when flumioxazine was used in the mixtures with herbicides acetochlor and propisochlor (long-chain fatty acid synthesis (LCFAS) inhibitors), promethrin (electron transport (ET) inhibitor in photosystem 2 (PS 2) of chloroplasts) and fluorochloridone (inhibitor of carotenoid synthesis by blocking the activity of phytoendesaturases (PDS)) both in the experiments on sunflower crops and in greenhouse experiments using the model objects. Results. The studies have shown that when flumioxazine is applied with the ET inhibitor, promethrin, the interaction is antagonistic, resulting in poor weed control efficiency and sunflower yield decrease. The tank mixtures of flumioxazine with LCFAS inhibitors acetochlor and propisochlor provide high weed control efficiency but are low in selectivity for sunflowers. The interaction between flumioxazine and fluorochloridone within the recommended application rates is additive. The tank mixture of flumioxazine and fluorochloridone herbicides at the application rates of 55 and 500 g/ha, respectively, is selective for sunflowers. In terms of control efficiency of annual dicotyledons, this mixture of herbicides exceeded, and in terms of control efficiency of annual cereal weed species was only slightly inferior to the control integrated herbicide (metolachlor + terbuthylazine). In these application rates, flumioxazine and fluo- rochloridone provided sunflower yield on par with this complex herbicide. Сonclusions. Among the investigated herbicides, the optimal partner of flumioxazine for complex use in sunflower crops was the herbicide, inhibitor PDS, fluorochloridone. Given that flumioxazine and fluorochloridone differ in their phytotoxicity mechanisms but share a common spectrum of controlled weed species, the use of a mixture of these herbicides is a factor that minimizes the likelihood of the emergence of herbicide-resistant weed biotypes.

Efficacy of New Herbicide Mixtures on Weed Control, Yield, and Economics in Transplanted Rice

Aim: To evaluate the efficacy of new herbicide mixtures on the weed control and performance of transplanted rice.
 Study Design: Randomized Complete Block Design.
 Place and Duration of Study: AlI India Coordinated Research Project on Weed Management, PJTSAU, Hyderabad between August to December, 2021.
 Methodology: The efficacy of herbicide mixtures either ready mix or as tank mixtures were evaluated for effective and broad spectrum weed control in transplanted rice during kharif season, 2021 at AICRP on Weed Management, PJTSAU, Rajendranagar, Hyderabad. The experiment was laid out in a randomized complete block design with nine treatments and three replications. The treatments included five ready mixes (RM) one tank mix combination of new herbicides tested against one single herbicide, weedy check and hand weeding twice at 20 and 40 DAT.
 Results: The results of the study revealed that bispyribac sodium 10% SC 25 g ha-1+ penoxsulam 1.02% (20 g ha-1) (tank mix) as post-emergence (POE) fb hand weeding (HW) at 40 DAT or penoxsulam 0.97% (20 g ha-1) + butachlor (38.8%) @ 820 g ha-1 (RM) as POE fb HW at 40 DAT or penoxsulam 1.02% (20g ha-1) + cyhalofop butyl 5.1% (100 g ha-1 ) (RM) as POE fb HW at 40 DAT or bensulfuron methyl 0.6% (60 g ha-1) + pretilachlor 6% (600g ha-1) GR (RM) as pre-emergence (PE) fb HW at 40 DAT were equally effective to hand weeding twice at 20 and 40 DAT with respect to suppression of weeds at 60 DAT. The yield attributes like a number of tillers/m2, panicles no, panicle length, grains panicle-1 and test weight were found to be higher with penoxsulam 1.02% (20 g ha-1) + cyhalofop butyl 5.1% (100 g ha-1) as POE fb HW at 40 DAT which also recorded higher grain yield, straw yield, gross returns, net returns and B-C ratio but it was found to be at par with other herbicide combinations.
 Conclusion: It can be concluded that new herbicide mixtures either as ready mix or tank mix performed better than sole application or hand weeding alone.

Effect of Tillage and Herbicides on Weeds and Yield of Maize (Zea mays L.)

Based on this study, it can be concluded that for achieving effective weed control, and higher maize yield and profitability, combinations of conservation tillage (zero tillage + 6 t ha-1 residue) with tank mixture of either atrazine + tembotrione + halosulfuron at 800+90+67.5 g ha-1 or atrazine + tembotrione + bentazone at 900 + 90 + 960 g ha-1 as post-emergence can be adopted.

Reduced Degradation of the Herbicide 4-Chloro-2-Methylphenoxyacetic Acid (MCPA) in Soil Induced by the Fungicide Mixture Mancozeb, Metalaxyl-M, and Chlorothalonil Used in Tank Mixtures and Spray Series

Pesticides are extensively used in agriculture to prevent infestation of crops, control plant-associated diseases and pests, and increase crop productivity. With regards to typical agricultural practice, tank mixing of two or more plant protection products or the subsequent applications of herbicides, fungicides, and insecticides are common application strategies to improve pest control. Our study provides evidence that the fungicide mixture consisting of mancozeb, metalaxyl-M, and chlorothalonil, each applied according to their recommended field rates, retarded the degradation of the phenoxy herbicide 4-chloro-2-methylphenoxyacetic acid (MPCA) in soil. MCPA dissipation times were between 1.6 and 1.9 days without and 2.5–3.5 days with co-applied fungicides. Furthermore, the proportions of extractable residues, non-extractable residues, mineralization, volatile organic compounds, and MPCA metabolism were altered by the fungicide mixture, i.e., considerably lower amounts of the main transformation product of MCPA, 4-chloro-2-methylphenol, were formed. The effects induced by the fungicides persisted throughout the experiment. Our results demonstrate that the current situation of considering individual active substances in the authorization process for plant protection products could lead to a discrepancy in the exposure assessment for humans and the environment. For specifically these cases, this calls into question whether the legally required level of protection is provided.

Response of Soybean (Glycine max (L.) Merr.) and Weed Control with Postemergence Herbicides and Combinations of Cytokinin Mixtures

A field study was conducted in 2015 and 2016 in Stoneville, MS, to evaluate the influence of cytokinin products on soybean injury and weed control when combined with common POST soybean herbicide treatments. Cytokinin treatments included no cytokinin mixture and two formulated cytokinin mixtures (kinetin-1 and kinetin-2) applied at 0.000227 kg ai ha−1. Herbicide treatments were no herbicide, glyphosate at 1.37 kg ae ha−1 alone and in combination with S-metolachlor at 1.42 kg ai ha−1 or fomesafen 0.395 kg ai ha−1. The addition of cytokinin treatments had no impact on soybean injury, plant height, or yield. Glyphosate plus fomesafen provided the greatest level of Palmer amaranth control, between 84 and 67%., 7 days and 28 days after treatment, respectively. Barnyardgrass control with glyphosate plus fomesafen was antagonized by one of two cytokinin products. To prevent possible reductions in herbicide efficacy, tank mixtures with cytokinin products should not be applied to soybean in POST herbicide applications.

Effect of herbicide tank mixes on crop infestation and yield of spring wheat

The article presents the results of studies of tank mixtures of herbicides in the sowing of spring wheat variety Novosibirskaya 15. The results of the studies showed that the studied tank mixtures of herbicides effectively fought against weeds - the technical efficiency of the tank mixture of herbicides Lastik Top, MKE + Magnum Super, VDG was 90.2 %, tank sweep Lastik Extra, EC + Ballerina Super, SE - 89.1 %. Reducing the adverse effects of weeds contributed to an increase in yield - the use of a tank mix of herbicides Lastik Top, MKE + Magnum Super, VDG allowed to obtain an increase in yield of 1.06 t/ha or 39.6 %, a tank mix of Lastik Extra, KE + Ballerina Super, SE – 1.08 t/ha or 40.0 % in comparison with the control variant.

CONTROL OF CORN POLLUTION IN THE CONDITIONS OF THE RIGHT-BANK FOREST STEPPE

This article presents the results of studies of the main elements and methods of controlling the development of weeds in corn crops and the identified changes in water and nutrient properties of the soil. The optimal tank mixtures and technological combinations of new soil and insurance herbicides have been determined, which provide a high level of technical efficiency on a wide species spectrum of weeds that clog corn crops. In particular, for farm conditions, the complex nature of the formation of the type of weediness, which changes during the growing season of the crop, was noted. The results of assessments of the dynamics of weed vegetation indicate a gradual increase in cenotic tension due to the gradual transition of dominant species of weeds, such as Chenopodium album L., Amaranthus retroflexus L., Echinochloa crus-galli L., Elytrigia repens (L.) Gould , Sonchus arvensis L, Cirsium arvense L., Convolvulus arvensis L. in the middle tier of sowing with a simultaneous increase in the frequency of their determination by 1.1-1.3 times. It was established that the best growth and development of the total leaf surface of corn plants (2.15-2.26 pcs./m2) was noted on the herbicide agro background and complete removal of weeds, and with natural weediness of the crops - a negative effect on growth processes, size and duration of functioning of leaves (1.14 pcs./m2). According to the research results, the technical efficiency against weeds of the first wave reached 100% when combining soil and insurance herbicides - Dual Gold - 1.5 l/ha (before sowing) + Stellar - 1.25 l/ha + Surfactant Metolate - 1.25 l/ha (by stairs); during the second and subsequent waves of weeds, protection systems that combine vegetative and soil deterrent effects are best controlled (Stellar - 0.8 l/ha + Akris - 1.5 l/ha + Surfactant Metolate - 0.8 l/ha and Kelvin Plus - 0.3 kg/ha + Akris - 1.5 l/ha + PA Hasten - 1 l/ha). The highest yield of corn grain (6.98 t ha-1 and 6.81 t ha-1) was obtained from the combination of soil and insurance preparations Akris (before sowing) + Kelvin Plus and PAR Hasten (after the steps) and Dual Gold (before sowing) + Stellar and surfactant Metolat (by stairs); Akris + Stellar + metolat surfactant (yield - 6.68 t ha-1) was singled out among post-emergence herbicide mixtures; with autonomous use of the preparations Stellar and Kelvin Plus, the yield was 6.35 t ha-1 and 6.22 t ha-1, respectively. The identical economic expediency of using such variants of herbicide application on corn Akris, 1.5 l/ha + Stellar, 0.8 l/ha + Metolat surfactant, 0.8 l/ha and Stellar, 1.25 l/ha + Metolat surfactant, has been confirmed ,1.25 l/ha, which was 43% higher than in the control with natural weeding and 33.2-33.4% higher than in the option of inter-row cultivation with manual weeding.

Эффективность применения баковых смесей гербицидов при возделывании масличного льна в условиях зон неустойчивого и недостаточного увлажнения Западного Предкавказья

We carried out the research in 2018–2020 to identify effective herbicide tank mixtures on oil flax under conditions of zones of unstable and insufficient moistening of the Western Ciscaucasia and to determine their impact on productivity and economic effectiveness of crop cultivation. We used established procedures of carrying out field agrotechnical experiments with oil crops. The object of research was oil flax varieties of breeding of V.S. Pustovoit All-Russian Research Institute of Oil Crops: in the zone of unstable moistening on leached chernozem (Krasnodar) FLIZ, in the zone of insufficient moistening on ordinary chernozem (vil. Oporny, Rostov region) Raduga. In the research years, the average yield of oi flax in the zone of unstable moistening was 1.29 t/ha, in the zone of insufficient moistening – 1.09 t/ha. The ap-plication of tank mixtures Miura, EC (1.2 l/ha) + Tifi, WDG (0.025 kg/ha) and Miura, EC (1.2 l/ha) + Magnum, WDG (0.01 kg/ha) reduces crop productivity, so they are not recommended for use in oil flax cultivation. We established the best effectiveness in the zone of unstable moistening with application of the tank mixture Miura, EC (1.2 l/ha) + Herbitox, SC (1.0 l/ha), in the zone of insufficient moistening – Miura, EC (1.2 l/ha) + Sekator Turbo, OD (0.1 l/ha).

Large-scale study investigating the effects of a tank mixture containing thiacloprid-prochloraz on honey bees (Apis mellifera)

Risk assessment of plant protection products (PPPs) will be conducted before authorization for their possible effects on non-target organisms, including honey bees. Tank mixtures are often common practice by farmers, and mostly their effects on honey bees are not routinely assessed. To enable a realistic assessment of laboratory-reported effects of a combination of the insecticide thiacloprid and fungicide prochloraz on honey bees, a large-scale field study with spray application in winter oilseed rape was conducted in four regions in Germany. Several parameters were investigated, including mortality, flight activity, and colony development. Residue analysis of various materials (e.g., dead bees, nectar, and pollen) was conducted to assess exposure level. We observed several intoxication symptoms 2 h after application, including a high number of moribund bees and dead bees on the first day after application (DAA +1) compared to the control. Adverse effects were observed on the number of open brood cells, with a significant reduction of approximately 22% compared to control over the experimental period. High residue concentrations were detected on flowers and dead bees on the day of application, which decreased rapidly within six days. The residue concentrations detected were higher in bee-collected materials than in materials stored in the hive. In conclusion, exposure to a combination containing thiacloprid-prochloraz poses a high risk to honey bees. Thus, the application of such a mixture on flowering crops is restricted in Germany.

Antagonistic Interactions between Dicamba and Glyphosate on Barnyardgrass (Echinochloa crus-galli) and Horseweed (Erigeron canadensis) Control

Dicamba plus glyphosate (DpG) tank mixture has been widely adopted for broad-spectrum weed control. However, recent studies indicated antagonistic interactions between these herbicides. Furthermore, little is known about the effect of non-ammonium sulfate water conditioner (non-AMS WC) adjuvant on the activity of DpG tank mixture. Thus, the present study was elaborated to evaluate (1) the interaction of DpG tank mixtures combinations on barnyardgrass, and glyphosate-susceptible (GS) and -resistant (GR) horseweed control, and (2) the effect of non-ammonium sulfate water conditioner (non-AMS WC) on the interaction of those two herbicides on the aforementioned weed species. Greenhouse experiments were conducted in 2020 at the Pesticide Application Laboratory in North Platte, NE. Herbicide treatments were arranged in a two-level factorial design of six dicamba rates by six glyphosate rates for Study 1, and in a three-level factorial design of two adjuvant treatments (presence or not of non-AMS WC) by four dicamba rates by four glyphosate rates for Study 2. Both trials were conducted as randomized complete block designs with four replications and two runs. Antagonistic interactions were observed throughout DpG treatments in GS and GR horseweed. For instance, dicamba (560 g ae ha−1) and glyphosate (1260 g ae ha−1) resulted in 72% of GR horseweed biomass reduction, compared to 81% of estimated biomass reduction. For barnyardgrass, antagonistic interactions were only observed within the reduced glyphosate rates. The addition of non-AMS WC had no effect on DpG antagonism. However, it improved the barnyardgrass control by glyphosate.

Glyphosate Efficacy in Chloris virgata Sw. in Response to Temperature and Tank Mixing

Glyphosate alone or a tank mixture of glyphosate and 2,4-D is commonly used for broad-spectrum weed control under fallow conditions in Australia. Air temperature or mixing glyphosate with 2,4-D, may influence the efficacy of glyphosate on feather fingergrass (Chloris virgata Sw.), a problematic summer-season weed of Australia. Dose-response studies were conducted with four populations of feather fingergrass under temperature-controlled glasshouse conditions (35/25 °C and 25/15 °C at 12 h/12 h) to assess the level of glyphosate resistance in relation to temperature regimes. Four parameter log-logistic models were used to develop dose-response curves. Based on plant mortality percentage, LD50 (lethal dose for 50% mortality) values of glyphosate at 25/15 °C for populations Ch, SGM2, SGW2, and CP2 were 137, 60, 650, and 1067 g ae ha-1, respectively. However, at 35/25 °C, the corresponding LD50 values were 209, 557, 2108, and 2554 g ae ha-1, respectively. A similar response was observed for the parameter GR50 (dose for 50% growth reduction) values of glyphosate. These results indicate that populations SGW2 and CP2 are highly glyphosate-resistant and in the summer season, it may be very difficult to control these populations due to poor glyphosate efficacy. These results further suggest that the efficacy of glyphosate for feather fingergrass control can be improved if applied during cooler temperatures (25/15 °C) or the spring season compared with warmer temperatures (35/25 °C) or the summer season. In another study, 2,4-D antagonized glyphosate remarkably in the CP2 (glyphosate-resistant) population but only marginally in the Ch (glyphosate-susceptible) population. Thus, it is not advisable to mix 2,4-D with glyphosate for the control of glyphosate-resistant feather fingergrass populations. The results further suggest that the use of this mixture is useful if the feather fingergrass is not glyphosate-resistant; however, the use of the mixture is to be avoided if the population is glyphosate-resistant in order to not exacerbate the potential resistance problem.

The effect of tank mixture of herbicides on the contamination of crops and productivity of spring wheat

Relevance. The main advantage of this method is its high biological efficiency (up to 90% or more) against the background of a quick payback from a significant increase in production due to the stored harvest. At the same time, in some cases, it becomes possible to manipulate the timing of the use of herbicides, taking into account their selectivity, operational qualities, as well as the industrial employment of the forces and means of an agricultural enterprise engaged in weed control. Therefore, the study and selection of modern herbicides in the fight against weeds is an urgent task of great practical importance.Methods. The object of research is a variety of spring soft wheat Zlata. The predecessor is potatoe. The seeding rate is 5.5 million. The scheme of the experiment included 2 options: 1) control (without the use of herbicides); 2) the use of a tank mixture of herbicides («Ballerina»+ «Bomba» + «Lastic Extra»). The sowing area of the crop is 3 ha, the area of the accounting plots is 50 m2, the repetition of the experiment is 3 times.Results. The conducted studies have shown that under experimental conditions, the share of juvenile monocotyledonous weeds in spring wheat crops accounted for 68.9%, of juvenile dicotyledonous weeds — for 31.1% of the total number. The most widespread among them were: Echinochla crusgalli — 68.9%, Chenopodium album — 13.1%, Amaranthus retroflexus — 6.2% and Galeopsis tetrahit — 5.2%. The use of a tank mixture of herbicides «Ballerina» + «Bomba» + «Lastic Extra» made it possible to reduce the number of weeds by 90.4–94.1%, reduce the loss of biological grain yield by 14%, ear weight —by 7%, productive bushiness — by 5%, weight of 1000 grains —by 2%, and also increase the yield of spring wheat grain by 0.68 t/ha and get an additional profit of 1.9 thousand rubles/ha.

The effect of temperature on hydrocarbon profiles and the microbial community composition in North Saskatchewan River water during mesoscale tank tests of diluted bitumen spills

Despite many studies of diluted bitumen (DB) behavior during spills in saltwater, limited information is available on DB behavior in fresh water. This study examined the collective weathering processes on changes of fresh DB spilled in the North Saskatchewan River water and sediment mixture in a mesoscale spill tank under average air/water temperatures of 14 °C/15 °C and 6 °C/2 °C. Temporal changes of the hydrocarbon and microbial community compositions in the water column were assessed during the two 35-day tests under intermittent wave action. The contents of total organic carbon (TOC), benzene/toluene/ethylbenzene/xylenes (BTEX) and polycyclic aromatic hydrocarbons (PAHs) in water decreased with time during both tests. The final contents remained at higher values in warm water (15 °C) than in cold water (2 °C) after the collective weathering processes. A quick response of the main phyla, Proteobacteria and Actinobacteria, was observed, where the members of Proteobacteria enriched during both DB spills. In contrast, the members of Actinobacteria reduced with time. The microbial shifts coincided with the changes of PAHs in the waters at both temperatures. A comparison of the physical properties and chemical compositions of fresh and weathered DBs at both temperatures showed that the oil had undergone weathering that increased oil density and viscosity due to losing the light oil fraction with boiling points < 204 °C and emulsifying with water. This corresponded to losses of 19.0 wt% and 17.2 wt% of the fresh DB at 15 °C and 2 °C tests, respectively. For organic compounds in the DB with boiling points > 204 °C, there were small losses of saturates and 2- & 3-ring PAH aromatics (more during the 15 °C test than the 2 °C test), and negligible losses in the subfractions of resins and asphaltenes by the ends of the tests. <1.0 wt% of the DB was recovered from the bottom sediment, regardless of the temperature.

Optimizing the application of acibenzolar-S-methyl and copper to control bacterial spot on fresh-market tomato

This study aimed to adjust the number of applications of acibenzolar-S-methyl (ASM) and copper in an integrated program for the control of bacterial spot on fresh-market tomato. Two field trials were carried out during 2018 and 2019. Four sets of number of weekly applications of ASM were evaluated (7, 9, 11, and 13 applications). In addition to these, four other treatments were included: two as a tank mixture compound [13 weekly applications of ASM + biostimulant and nine applications of ASM + copper oxychloride]. Copper oxychloride was applied after ASM treatments in order to complete 13 applications per growing season. Copper oxychloride and untreated plots were used as a control. The variables evaluated were bacterial spot severity, total yield, and yield per classes of fruit according to the Brazilian market standards. Benefit-cost ratio (B/C) was calculated considering the income increase of a given treatment in relation to the untreated control. The disease ratings and yield data were subjected to ANOVA and the means tested for significance by Fisher, Dunnett, and orthogonal contrasts comparison tests. Regression analysis were carried out with the disease ratings to evaluate the ASM number of applications. As the number of ASM applications increased, disease severity decreased, although, the best B/C was obtained with seven applications of ASM, followed by copper applications until the end of the cycle. The tank mixture compound treatments did not result in economic gain increase. Moreover, disease severity was significantly high when ASM was applied in tank mixture with copper.