Organosilicone Surfactant Research Articles

Characterization of a plant‐pathogenic T3SS‐lacking Xanthomonas strain isolated from common ragweed

AbstractCommon ragweed (Ambrosia artemisiifolia) is one of the leading causes of allergenic rhinitis, as well as a major weed of many crops. Biological control with plant pathogens, such as fungi and bacteria, represents an attractive alternative to the application of synthetic herbicides to control this noxious weed. In this study, we isolated a Xanthomonas strain (designated as 10‐10) from a diseased common ragweed plant collected in southern Quebec, Canada. We characterized the bioherbicidal potential of this strain against common ragweed, and determined whether it can infect other plant species. Its genome was sequenced using PacBio's SMRT technology, enabling us to gain insight into the phylogenetic placement of this strain within the genus Xanthomonas, and to study the repertoire of virulence‐associated genes and clusters. Xanthomonas sp. 10‐10 belongs to a clearly defined subclade within clade C (group 2), which includes X. vesicatoria, X. dyei and X. pisi. While this strain is closely related to X. pisi, it represents a new species within the genus Xanthomonas. Surprisingly, this strain lacks a type III secretion system, which is the main virulence determinant in pathogenic Xanthomonas spp., but harbours an arsenal of cell wall‐degrading enzymes. The addition of the organosilicone surfactant Silwet L‐77 drastically increased the disease symptoms caused by Xanthomonas sp. 10‐10 on common ragweed plants grown under controlled conditions, but the plants remained alive. This strain also caused disease symptoms on tomato, pepper and lettuce. More research is needed to develop Xanthomonas‐based bioherbicide specifically targeting common ragweed.

Effect of water hardness and surfactant on the particle coverage and distribution of plant protection products granules

The paper presents a study done to determine how particles of different plant protection products (fungicides) are distributed onto treated surfaces when their solutions are prepared with water of different hardness and addition of surfactant. A total of fifteen plant protection products were studied, all in the same concentration of 0.3% with four type of solutions: only distilled water, distilled water plus a wetting agent – the organosilicone surfactant – Silwet L-77, very hard tap water (hardness = 196.9 ррm СаСО3, 11 °dH) and very hard tap water plus wetting agent. The observations and images were made via light microscope with magnification 200X and 3MP digital camera. The images were analyzed for a percent distribution, and spreading of particles by ImageJ software. The results showed that the distribution, and coverage of particles onto treated surfaces can be different even at application of similar plant protection products. The variations in the properties were observed when the solutions were made with waters with different hardness and a wetting agent was added to the solutions. Contrary to the common perception that hard water can reduce the effectiveness of pesticides towards pests, according to the distribution and coverage of particles onto treated surfaces, in some cases hard water can even enhance these properties of the pesticide solutions. Keywords: plant protection products, distribution, coverage, wetting agent, water hardness

Hyperbranched Organosilicon Surfactants as Emulsifiers for the Emulsion Polymerization of Methyl Methacrylate

This report is devoted to the investigation of the emulsion polymerization of methyl methacrylate in the presence of PEGylated hyperbranched polymethylethoxysiloxane as an emulsifier. It is shown that its use in the amount of 1–5 wt % affords stable 25–50% poly(methyl methacrylate) dispersions with the controlled particle sizes from 300 to 800 nm and a narrow particle size distribution.

Active ingredient identification and purification of organosilicon spray adjuvant and its uptake and translocation in rice (Oryza sativa L.).

The assessment of residue, absorption, conduction, and degradation of agricultural organosilicon surfactants in the environment is hindered by the lack of information on active ingredients and corresponding quantitative standards for organosilicon spray adjuvants. The spray adjuvant 'Jiexiaoli,' a primary organosilicon spray agent in China, was identified as hydroxy (polyethylene) propyl-heptamethyl trisiloxane (TSS-H) with 3-15 ethoxy (EO) groups. Purification of TSS-H was achieved through semi-preparative separation using high-performance liquid chromatography (HPLC), resulting in TSS-H purity exceeding 96%. An accurate residual detection method for nine oligomers (4-12 EO) of TSS-H in rice roots, stems, leaves, and culture solution samples was developed using HPLC tandem high-resolution mass spectrometry (HPLC-HRMS). Recoveries for nine oligomers of TSS-H in the four matrices ranged from 80.22% to 104.01%. Foliar application experiments demonstrated that TSS-H did not transfer from the upper to the lower parts of the rice plant. The half-lives of each oligomer (4-12 EO) in leaves were less than 3.21 days. Root application experiments revealed a root concentration factor (RCF) ranging from 0.20 to 0.56, a biological enrichment factor (BCF) ranging from 0.36 to 0.68, a transpiration factor (TSCF) ranging from 0.069 to 0.086, and a transport factor (TF) ranging from 0.08 to 0.43. These results indicated that TSS-H could be absorbed by rice roots and conducted to the above-ground parts of rice plants. This study fills the data gap in the environmental risk and food safety assessment of agricultural silicone spray adjuvants. © 2024 Society of Chemical Industry.

Control of Pierce's Disease of Grape with Paraburkholderia phytofirmans PsJN in the Field.

Replicated field studies were conducted to evaluate the factors that could influence the efficacy of Paraburkholderia phytofirmans PsJN for the control of Pierce's disease of grape, as well as to determine the extent to which disease control was systemic within plants. Topical applications of PsJN with an organosilicon surfactant was an effective way to introduce this bacterium under field conditions and provided similar levels of disease control as its mechanical inoculation. Disease incidence in inoculated shoots was often reduced two- to threefold when PsJN was inoculated a single time as much as 3 weeks before Xylella fastidiosa and up to 5 weeks after the pathogen. Inoculation of a shoot with PsJN greatly decreased the probability of any symptoms rather than reducing the severity of disease, suggesting a systemic protective response of individual shoots. Although the likelihood of disease symptoms on shoots inoculated with the pathogen on PsJN-treated plants was lower than on control plants inoculated only with the pathogen, the protection conferred by PsJN was not experienced by all shoots on a given plant. This suggested that any systemic resistance was spatially limited. Whereas the population size of PsJN increased to more than 106 cells/g and spread more than 1 m within 12 weeks after its inoculation alone into grape, its population size subsequently decreased greatly after about 5 weeks, and its distal dispersal in stems was restricted when co-inoculated with X. fastidiosa. PsJN may experience collateral damage from apparent host responses induced when both species are present.

Construction and performance of waterborne organosilicon anti-fouling coating based on hydrosilylation

Under the background of “Dual Carbon” strategy, the coating technology of silicon-based materials replacing carbon-based materials has become a research hotspot. Owing to high-viscosity characteristic of raw materials involving divinyl-terminated polydimethylsiloxane (ViPDMSVi) and reinforcing components, existing approaches for the preparation of organosilicon coatings by hydrosilylation still consume a large amount of organic solvents, causing environmental pollution and inconsistent with the low-carbon strategy. Herein, a robust strategy to prepare hydrosilylation waterborne organosilicon coatings via rational design of the emulsification system to obtain two-component aqueous emulsions is reported. In this strategy, two reactive organosilicon surfactants were synthesized and compounded with corresponding anionic surfactants for emulsification of vinyl organosilicon components and polymethylhydrosiloxane (PMHS), respectively. The resultant two emulsions were cured via hydrosilylation to obtain the desired coating. Additionally, vinyl MQ resin was selected as reinforcing component to increase the density of the coating. The facts that water, ethanol, mud water and other common liquids can slide off cleanly, and oily markers on the coating surface can be easily wiped off, indicate the outstanding anti-fouling properties of the coating. Furthermore, even under various harsh environments such as high temperature, ultraviolet radiation and chemical corrosion, the coating still shows good anti-fouling performance. This work opens up a viable avenue for the preparation of waterborne organosilicon anti-fouling coatings.

Smooth scouringrush (Equisetum laevigatum) control with glyphosate is affected by surfactant choice and application time

AbstractSmooth scouringrush is a creeping perennial with a high silica content in stems that may impede herbicide uptake. Smooth scouringrush has become a troublesome weed in no-till cropping systems across eastern Washington. In previous field studies, glyphosate provided inconsistent control of smooth scouringrush. The objective of this study was to determine if the addition of an organosilicone surfactant to glyphosate would improve the efficacy and consistency of control through stomatal flooding. To test this hypothesis, glyphosate was applied at three field sites at 3.78 kg ae ha–1 alone, with an organosilicone surfactant (OS1 or OS2), an organosilicone plus nonionic surfactant blend, or an alcohol-based surfactant applied during the day or at night. Stem counts were recorded 1 yr after herbicide applications. Five of the six effective treatments observed across the three study sites included organosilicone surfactant or an organosilicone plus nonionic surfactant blend. At two sites, when there was a difference in efficacy between application times; daytime applications were more effective than nighttime applications. These results support the hypothesis of stomatal flooding as a likely mechanism for enhanced efficacy of glyphosate with the addition of an organosilicone surfactant. However, at one site, the treatments containing organosilicone surfactant were more efficacious when applied at night than during the day. At this site, high daytime temperatures and low relative humidity may have resulted in rapid evaporation of spray droplets. The addition of an organosilicone surfactant to glyphosate is recommended for smooth scouringrush control, and daytime treatments are preferred but should be applied when temperatures and humidity are not conducive to rapid droplet drying. Further research is necessary to confirm that stomatal flooding is responsible for improved glyphosate efficacy.

A selected organosilicone spray adjuvant does not enhance lethal effects of a pyrethroid and carbamate insecticide on honey bees.

As part of the agricultural landscape, non-target organisms, such as bees, may be exposed to a cocktail of agrochemicals including insecticides and spray adjuvants like organosilicone surfactants (OSS). While the risks of insecticides are evaluated extensively in their approval process, in most parts of the world however, authorization of adjuvants is performed without prior examination of the effects on bees. Nevertheless, recent laboratory studies evidence that adjuvants can have a toxicity increasing effect when mixed with insecticides. Therefore, this semi-field study aims to test whether an OSS mixed with insecticides can influence the insecticidal activity causing increased effects on bees and bee colonies under more realistic exposure conditions. To answer this question a pyrethroid (Karate Zeon) and a carbamate (Pirimor Granulat) were applied in a highly bee attractive crop (oil seed rape) during bee flight either alone or mixed with the OSS Break-Thru S 301 at field realistic application rates. The following parameters were assessed: mortality, flower visitation, population and brood development of full-sized bee colonies. Our results show that none of the above mentioned parameters was significantly affected by the insecticides alone or their combination with the adjuvant, except for a reduced flower visitation rate in both carbamate treatments (Tukey-HSD, p < 0.05). This indicates that the OSS did not increase mortality to a biologically relevant extent or any of the parameters observed on honey bees and colonies in this trial. Hence, social buffering may have played a crucial role in increasing thresholds for such environmental stressors. We confirm that the results of laboratory studies on individual bees cannot necessarily be extrapolated to the colony level and further trials with additional combinations are required for a well-founded evaluation of these substances.

Voltage dependence of rock meal based foliar fertilizers with ISR properties, water solutions

The electrical conductivity of several rock meal based fertilizers with expressed ISR activity, measured as voltage dropping when their distilled water solution was affected with low – voltage electric currents of 5 volts (DC and AC) was examined. For comparison, hard and soft tap water (with 196 and 65 ppm CaCO3 hardness), 1% distilled water solutions of NaCL and CuSO4.5H2O solution and 0.1% solution of organosilicone surfactant were also tested in the conducted trials. The result shows that hard water, solutions of NaCL and CuSO4.5H2O and solutions of fertilizers with fulvic acids content can cause drops in the voltage of electric currents. The same results were received for the fertilizer on the basis of K2O, SiO2, Cu, although other products with similar content do not cause a voltage decrease. There were no differences in the conducted tests between the DC and AC electric currents.

Insecticidal Activity of a Petroleum-Derived Spray Oil and an Organosilicone Surfactant on Listronotus maculicollis (Kirby) Adults in Laboratory and Greenhouse Bioassays.

The annual bluegrass weevil (ABW), Listronotus maculicollis (Kirby), is a severe pest of golf course turf in eastern North America. The development of pyrethroid- and multiple-resistant populations has created a dire need for novel tactics to control adults. We examined the insecticidal properties of a petroleum-derived spray oil (PDSO; Civitas Turf Defense™.) and an organosilicone, nonionic soil surfactant (Silwet L-77®) in laboratory and greenhouse bioassays. Civitas and Silwet killed &gt; 75% of ABW adults in multiple assays. The level of control was positively affected by increased rate, spray application volume, and soil moisture levels. Dissections of weevils treated with Civitas revealed material entering the insect's hemocoel after 15-30 min, though most mortality occurred between the 3 and 24 h observation periods. Reducing rates while increasing carrier volume or soil moisture levels through irrigation applied prior to or after application also provided excellent control of adults in the same observation periods. Silwet provided comparable, yet less consistent levels of control in the laboratory studies but was excluded from further tests after treated plants demonstrated phytotoxicity in greenhouse studies. Neither Silwet nor Civitas efficacy was affected by pyrethroid resistance levels in the ABW populations tested.

Effect of oil-based emulsion on air bubbles in the spray sheet produced through the air-induction nozzle.

The air-induction spray featured by air bubbles involved in the spray sheet has attracted great attention in applications of agricultural spray due to its advantages of alleviating spray drift and promoting deposition. The objective of the presented study is to deepen the understanding of the mechanism of the air-induction spray through elucidating the effect of sprayed liquid on characteristics of air bubbles in the spray sheet. The air bubbles with relatively large sizes are stable for a long time span. As velocity of the water spray increases from 6.85 m s-1 to 17.87 m s-1 , average size of the air bubbles decreases from 383.21 μm to 236.47 μm. With the introduction of organosilicone surfactant, the surface tension of the sprayed liquid decreases from 67.38 mN m-1 to 31.32mN m-1 ; accordingly, average size of the bubbles decreases from 383.21 μm to 160.9μm. Compared to aqueous solutions spray, the oil-based emulsion spray is responsible for relatively small average size of air bubbles as the surface tension and spray velocity are respectively similar. Low drainage rate of the bubble lamella contributes to high stability of large air bubbles. The decrease of the average size of air bubbles is responsible for small volumetric median diameter of oil-based emulsion spray compared with water spray. Besides the increase of the spray velocity and the decrease of the surface tension, the Marangoni effect caused by dynamics of oil droplets at air-liquid interface also contributes to the decrease of average size of air bubbles. © 2022 Society of Chemical Industry.

Synthesis of polymer suspensions in the presence of organosilicon surfactants of various nature

The colloid-chemical properties of organosilicon surfactants with different solubility in water were studied. The behavior of organosilicon surfactants of various structures in model systems - Langmuir films at the water-air interface has been studied. The results obtained showed that high stability of polymer suspensions is observed only in the presence of insoluble in water organosilicon surfactants.

Smooth scouringrush (Equisetum laevigatum) control with glyphosate in eastern Washington

AbstractSmooth scouringrush has invaded no-till production fields across the US Pacific Northwest. The ability of Equisetum species to take up and accumulate silica on the epidermis and in cell walls may affect herbicide uptake. The objectives of this study were to measure the silica concentration in smooth scouringrush stems over time, and to determine how time of application affects the efficacy of glyphosate for smooth scouringrush control, with and without the addition of an organosilicone surfactant (OSS). Field studies were conducted at three sites in eastern Washington from 2019 to 2021. Three herbicide treatments (no herbicide, glyphosate, and glyphosate + OSS) were applied at four application times (May, June, July, and August) in 2019 fallow. The silica content of smooth scouringrush stems increased over the course of the 2019 growing season at all three sites. In 2020, smooth scouringrush stem densities were reduced when the 2019 herbicide treatments were applied in late June (12% of no herbicide density) compared to late July (24%) or August (30%). Smooth scouringrush stem densities at all three sites, in both 2020 and 2021, were reduced in the glyphosate + OSS treatment compared to glyphosate alone. In 2021, 2 yr after herbicide application, there was no effect of application timing for the glyphosate treatment without OSS, but stem densities were reduced when glyphosate + OSS was applied in late June (1%) compared with applications in late July (26%) or late August (21%). It is not clear if the cause of reduced glyphosate efficacy with late July and late August applications is the result of increased silica content in smooth scouringrush stems over time. Maximum glyphosate efficacy on smooth scouringrush was achieved with an application in late June and with the addition of an OSS. Control of smooth scouringrush with glyphosate + OSS can be sustained for at least 2 yr after application.

Polymer-monomer particles formation and particle size distribution during heterophase polymerization in the presence of water-insoluble organosilicon surfactant

In this work mechanism of polymer particles formation during styrene heterophase polymerization in the presence of waterinsoluble organosilicon surfactant was investigated. Dependency between monomer conversion rate from early stages of polymerization and particle diameters change, molecular weight, particle size and molecular weight distribution was analyzed. The effect of the gel effect and Ostwald maturation on particle diameter and polymer molecular weight was evaluated.

Evaluation of Abamectin as a Potential Chemical Control for the Lychee Erinose Mite (Acari: Eriophyidae), a New Invasive Pest in Florida

The lychee erinose mite, Aceria litchii (Keifer) (Acari: Eriophyidae), is an important pest of lychee (Litchi chinensis Sonn.; Sapindaceae) trees. This minute mite prefers to feed on young, new flush causing the formation of galls called “erinea.” Chemical control to protect the new flush is the primary management approach that has been used to control this mite. Aceria litchii was detected recently in Lee County, Florida, USA, and there is an urgent need to identify an acaricide that can control mite populations. Among the acaricides registered for use on lychee in Florida, abamectin was reported to be effective against A. litchii from other parts of the world. However, it remains unknown whether this acaricide can control the mites inside the erinea effectively and protect the new flush. We investigated whether abamectin alone or in combination with an organosilicone surfactant could control an existing mite infestation. Lychee leaflets that had erinea were sprayed with acaricides, then placed on uninfested plants and monitored for symptom development. One mo after placing treated leaflets on uninfested plants, the same treatment was applied to the whole plants and monitored for erinea development on the new flush. Our results showed that none of the treatments were able to control the mites inside the erinea and protect the new flush. The methods described here can be used for more precise evaluations of other acaricides that are urgently needed to control A. litchii in Florida.

Toxicity and Control Efficacy of an Organosilicone to the Two-Spotted Spider Mite Tetranychus urticae and Its Crop Hosts.

Simple SummaryThe organosilicone is commonly used as surfactant ingredient in agriculture. Some pilot studies showed pesticidal activities of some organosilicone surfactants. This study examined the toxicity of an organosilicone, Silwet 408, to the two-spotted spider mite Tetranychus urticae and explored the field usage of this chemical in pest control. We tested this chemical on eggs, nymphs, and adults of T. urticae. We applied a two-sprays strategy to enhance the field control efficacy based on the high toxicity of Silwet 408 to nymphs and adults and the lack of toxicity to eggs of T. urticae. However, their phytotoxicity should be taken under consideration. Our study improved our understand of the toxicity and safety of organosilicone surfactants. The results provide a basis for the usage of this chemical in mite control.Organosilicone molecules represent important components of surfactants added to pesticides to improve pest control efficiency, but these molecules also have pesticidal properties in their own right. Here, we examined toxicity and control efficacy of Silwet 408, a trisiloxane ethoxylate-based surfactant, to the two-spotted spider mite (TSSM), Tetranychus urticae and its crop hosts. Silwet 408 was toxic to nymphs and adults of TSSM but did not affect eggs. Field trials showed that the control efficacy of 1000 mg/L Silwet 408 aqueous solution reached 96% one day after spraying but declined to 54% 14 days after spraying, comparable to 100 mg/L cyetpyrafen, a novel acaricide. A second spraying of 1000 mg/L Silwet 408 maintained control efficacy at 97% when measured 14 days after spraying. However, Silwet 408 was phytotoxic to eggplant, kidney bean, cucumber, and strawberry plants, although phytotoxicity to strawberry plants was relatively low and declined further seven days after application. Our study showed that while the organosilicone surfactant Silwet 408 could be used to control the TSSM, its phytotoxicity to crops should be considered.

Organosilicon Surfactants as Antitumor Agents

Organosilicon Surfactants as Antitumor Agents

Influence of emulgator nature on dispersity and stability of artificial polymer suspensions based on polycarbonate and polymethyl methacrylate

Objectives. To create stable artificial polymer suspensions with a positive charge of particles based on polycarbonate and polymethyl methacrylate using cationic surfactants and organosilicon surfactants.Methods. The size of droplets and polymer suspension particles was determined by photon correlation spectroscopy (dynamic light scattering) using a Zetasizer NanoZS laser particle analyzer (Malvern, UK).Results. Domestic cationic surfactants Katamin-AB and Azol-129 were found to be capable of producing stable artificial polycarbonate and polymethyl methacrylate suspensions. Based on the polymer, the optimal surfactant concentration was 6 wt %. The effect of polymer concentration in solution on the stability and particle size of final polymer suspensions was shown. It was determined that the polymer concentration in the solution should not exceed 10%. When obtaining a highly dispersed suspension during dispersion, a higher concentration causes an increase in the viscosity of emulsions. As a result of a synergistic effect formation, we used mixtures of cationic surfactants (Katamin-AB/Azol-138 and Azol-129/Azol-138) to enhance the stability of the final polymer suspensions. The optimal surfactant ratio was 9:1. The total concentration of the mixture is 10 wt %, based on the polymer. Polymer suspensions were stabilized with each of 2:1 mixtures of cationic surfactants Katamin-AB and Azol-129 withan organosilicon surfactant U-851. The total mixture concentration was 9 wt %, based on the polymer.Conclusions. New methods of producing artificial polycarbonate and polymethyl methacrylate suspensions in the presence of domestically produced cationic surfactants, as well cationicorganosilicon surfactants mixtures, were proposed. The colloidal-chemical properties of the obtained polymer suspensions were considered. It was found that using a 2:1 mixture of cationic and organosilicon surfactants produces polymer suspensions that are stable during production and storage.

Experimental Treatment of Biopreparation Based on Pseudomonas Syringae pv. Tagetis for Weeds Control

Cirsium arvense is one of the worst weeds in agriculture. As actual herbicides are not very effective and not accepted by organic farming or in order to reduce the cantity of herbicides used, possible biocontrol agents have been investigated since many decades. The work carried out aimed at obtaining and assessing the herbicidal potential of bacterial preparation based on Pseudomonas syringae pv. tagetis (PST) for biological control of Cirsium arvense (L.) Scop. Silibase 2848P, an organosilicone surfactant, was required to facilitate PST penetration into creeping thistle leaves. The experiments were conducted under controlled conditions (growth chamber) to determine the concentration of Silibase 2848P required for the maximum penetration of PST into creeping thistle leaves. As well as to evaluate disease incidence in emerging leaves, and to quantify the effects of inundative foliar application on fresh and dry weights of shoots. In field conditions, efficacy of PST applications was assessed in terms of disease incidence and effect on shoot height, number of flower buds and survival of C. arvense. Maximum disease severity were recorded when PST was applied at a concentration of 10 x 108 cfu/ml + Silibase 0.3%.

Inert agricultural spray adjuvants may increase the adverse effects of selected insecticides on honey bees (Apis mellifera L.) under laboratory conditions

Currently, more than 360 spray adjuvants are registered in Germany (September 2021). Unlike plant protection products (PPPs), adjuvants are not subjected to regulatory risk assessment. In practice, numerous combinations of PPPs and adjuvants are therefore possible. Thus, tank mixtures containing insecticides that are classified as non-hazardous to bees up to the highest approved application rate or concentration may raise pollinator safety concerns when mixed with efficacy increasing adjuvants and applied in bee-attractive crops. This study analyzes whether selected “PPP–adjuvant” combinations result in increased contact mortality and pose an elevated risk to honey bees. To answer this question, we chose six common spray adjuvants of different classes for laboratory screening. These were then tested in a total of 30 tank mixtures, each with a neonicotinoid (acetamiprid), pyrethroid (lambda-cyhalothrin), diamide (chlorantraniliprole), carbamate (pirimicarb), and butenolide (flupyradifurone) formulation. We adapted an acute contact test (OECD Test Guideline 214) to our needs, e.g., by using a professional spray chamber for more realistic exposures. Our results showed that, in total, 50% of all combinations significantly increased the mortality of caged honey bees in comparison with individual application of insecticides. In contrast, none of the adjuvants alone affected bee mortality (Cox proportional hazard model, p > 0.05). With four of the five insecticide formulations, the organosilicone surfactant Break-Thru® S 301 significantly increased bee mortality within 72 h (for all insecticides except chlorantraniliprole). Furthermore, acetamiprid yielded the highest and second highest mortality increases from a tank mixture with the crop oil surfactant LI 700® (hazard ratio = 28.84, p < 0.05) and the organosilicone Break-Thru® S 301 (hazard ratio = 14.66, p < 0.05), respectively. To assess risk in a more field-realistic setting, field trials should be performed to provide a more realistic exposure scenario under colony conditions.