Agricultural Adjuvants Research Articles

Biosurfactants: Promising Biomolecules for Agricultural Applications

Population growth and the need for increased agricultural productivity pose a global problem. Therefore, the development of green compounds to ensure agricultural sustainability is an urgent necessity. Surfactant compounds hold significant commercial importance due to their diverse industrial uses. However, the synthetic origin of these agents limits their commercial application due to their toxicity. As a result, extensive research has focused on the production of microbial-originated green surfactants, known as biosurfactants, over the past fifteen years. These biomolecules not only offer a green alternative for agriculture but also exhibit reduced toxicity and excellent stability under specific environmental conditions. Biosurfactants can lower surface tension more effectively than synthetic surfactants. With properties such as detergency and foam formation, biosurfactants are suitable for various agricultural applications, particularly in pesticide and agrochemical formulations. They can function as biopesticides to manage pests, pathogens, phytopathogenic fungi, and weeds due to their antimicrobial activity. Moreover, plants can benefit from biosurfactant molecules and microorganisms as nutrients. They can also aid efficiently in the distribution of micronutrients and metals in the soil. They also stimulate plant immunity and are utilized for soil hydrophilization to ensure proper moisture levels and uniform fertilizer distribution. This review aims to provide valuable insights into the role and properties of biosurfactants as agricultural adjuvants, fostering the development of sustainable formulations to replace the chemical surfactants used in pesticides. For this purpose, the general aspects of global agricultural activity are initially described, followed by a discussion of pesticides, including herbicides, fungicides, and insecticide products. Next, the properties of chemical surfactants are discussed and the use of green surfactants, with emphasis on microbial biosurfactants, is demonstrated. The application of biosurfactants in the agricultural industry and trends are addressed and prospects for the application of these agents are discussed.

Review: the risks of spray adjuvants to honey bees.

Pesticide applications are often made as tank mixes containing multiple pesticide products and may include spray adjuvants to enhance pesticidal activities. The primary aim of adjuvant products is to increase the spreading and sticking of spray droplets and to increase the penetration of active ingredients through the cuticles of leaves or targeted pests, which can reduce the amount of active ingredient needed for effective pest control. Adjuvants are made up of compounds drawn from the "inert ingredient" list maintained by EPA but are identified as "principal functioning agents" when used in adjuvant products. These inert compounds do not undergo the same testing and risk assessment process that is required of pesticide active ingredients and generally have no mitigation measures that prevent application onto crops during bloom at times of day when bees are foraging. Honey bees (Apis mellifera;Hymenoptera:Apidae) are at an increased risk of exposure to adjuvant tank mixtures while providing agricultural pollination services. Colony losses attributed to pesticide applications thought to have low risk to honey bees have been reported, highlighting the need to better understand the toxicity of adjuvants included in pesticide tank mixtures. This review summarizes current literature on the risks posed to honey bees by agricultural adjuvants and tank mix combinations of adjuvants with pesticides. Based on the current state of knowledge, we make recommendations to pesticide applicators, product manufacturers, regulatory agencies, and researchers regarding adjuvant toxicity to honey bees with the goal of reducing risks that adjuvants pose to honey bees and other beneficial insects.

Preparation, Characterization, and Properties of Alkali-Resistant and Hydrolysis-Resistant Silicone Surfactant

It is a challenge to research and develop silicon surfactants with good acid and alkali stability. In the present paper, methylpropenyl polyether modified nonionic silicone surfactant (MPNTS), an alkali-resistant and hydrolysis-resistant silicone surfactant, was synthesized by hydrosilylation of 1,1,1,3,5,5,5-heptamethyl trisiloxane (MDHM) and methylpropenyl polyether (EO(7)). The polyether segments are grafted onto the main chain of organosilicon heptamethyl trisiloxane at a molar ratio of 1:1.05 (n(Si-H):n(C=C)). To evidence product formation, the MPNTS were analyzed by FT-IR and 1H NMR spectroscopy. The surface tension of NPNTS is 18.68 mN/m, and the CMC value is 78 mg/L by a contact angle tester. MPTNS shows hydrolytic stability and maintains that it could keep surface activity after standing for 60 days at pH = 7–10. The compatibility performance analysis shows that MPNTS has good compatibility and synergy with cationic, anionic, and nonionic surfactants, and it reveals the application prospects in daily chemicals, agricultural adjuvants, and other products.

Coacervate-Enhanced Deposition of Sprayed Pesticide on Hydrophobic/Superhydrophobic Abaxial Leaf Surfaces.

Deposition of high-speed droplets on inverted surfaces is important to many fundamental scientific principles and technological applications. For example, in pesticide spraying to target pests and diseases emerging on abaxial side of leaves, the downward rebound and gravity of the droplets make the deposition exceedingly difficult on hydrophobic/superhydrophobic leaf underside, causing serious pesticide waste and environmental pollution. Here, a series of bile salt/cationic surfactant coacervates are developed to attain efficient deposition on the inverted surfaces of diverse hydrophobic/superhydrophobic characteristics. The coacervates have abundant nanoscale hydrophilic/hydrophobic domains and intrinsic network-like microstructures, which endow them with efficient encapsulation of various solutes and strong adhesion to surface micro/nanostructures. Thus, the coacervates with low viscosity achieve high-efficient deposition on superhydrophobic abaxial-side of tomato leaves and inverted artificial surfaces with a water contact angle from 170° to 124°, much better than that of commercial agricultural adjuvants. Intriguingly, the compactness of network-like structures dominantly controls adhesion force and deposition efficiency, and the most crowded one leads to the most efficient deposition. The tunable coacervates can help comprehensively understand the complex dynamic deposition, and provide innovative carriers for depositing sprayed pesticides on abaxial and adaxial sides of leaves, thereby potentially reducing pesticide use and promoting sustainable agriculture.

Functional silicone oils and elastomers: new routes lead to new properties.

Silicones are mostly utilized for their stability to a range of vigorous environmental conditions, which arises, in part, from the lack of functionality in finished products. The commonly used functional groups in silicones, e.g., SiH, SiCHCH2, are mostly consumed during final product synthesis. Organic functional groups may also be found in silicone products, including organic alcohols, amines, polyethers, etc., that deliver functionality not achieved by traditional organic polymers (e.g., aminosilicones, softening of fabrics; silicone polyethers, superwetting agricultural adjuvants). However, relatively little organic chemistry is practiced in commercial silicones, limiting the types of desirable functionality that can be attained. We report the utilization of a series of simple-to-practice organic reactions that take place efficiently on silicone oils to allow the preparation of a wide variety of functional silicones. The silicone oil starting materials typically act as both solvent and educt to allow many of the newer reactions, such as Click processes, to be used to tune the properties of both silicone oil and elastomer products. The review considers the concept of 'functionality' to include: the reactive groups used to enable synthesis of more complicated structures; and separately, the functional properties of the product silicones. One such property that is considered throughout is degradability at end-of-life, which is related to the sustainability of silicones.

Agricultural adjuvants market

Agricultural adjuvants market

Effectiveness of coffee leaf miner control associated with spray deposition in coffee leaves

ABSTRACT Coffee production faces challenges due to the susceptibility of the crop to insects. Owing to the coffee leaf miner Leucoptera coffeella, which is one of the main insect pests, the technology for the application of phytosanitary measures becomes the main challenge for coffee growers. This study aimed to evaluate the effectiveness of coffee leaf miner control using different methods of application. The study was conducted in an experimental site in the municipality of Monte Carmelo - Minas Gerais. Spray depositions in different positions of the plant canopy and the effective control of coffee leaf miner were evaluated using the following application treatments: a hydropneumatic sprayer with varying spray volumes (200 and 400 L ha-1), two hollow-cone spray nozzles with the presence and absence of agricultural adjuvant, and electrostatic application using a spray volume of 200 L ha-1 with and without spray adjuvant. The addition of an adjuvant to the spray did not influence coffee leaf miner control; in contrast, a spray volume of 200 L ha-1 combined with the application of coarse droplets was efficient in the management of insect pest. The reduction in the rate of the application using coarse droplets increased the operational capacity and reduced spray drift potential.

Synthesis and properties of a glucono-δ-lactone-modified silicone surfactant from high-amine-value amodimethicone

High-amine-value aminopropyl polysiloxanes (APSO) were designed and synthesized via two different methods. APSO was then aminated with glucono-δ-lactone (GL) to produce sugar-modified amodimethicone (GLAP). The properties of GLAP were investigated systematically. GLAP has a low critical aggregation concentration (CAC) and displays low surface tensions at CAC (γCAC). GLAP forms spherical aggregates in solution. Formation of micelles and adsorption at the air-water interface are spontaneous. Moreover, its good solubility and excellent wetting properties make GLAP a potential candidate for application in paints, coatings, and agricultural adjuvants.

Effect of phytosanitary spray solution storage time on the viability of Beauveria bassiana conidia1

ABSTRACT Adverse weather conditions, or mechanical problems and decrease in the application rate, may increase the storage time of the spray solution in the sprayer tank. This study aimed to assess the effect of the phytosanitary spray solution storage on the germination of Beauveria bassiana conidia, with or without agricultural adjuvants. A completely randomized design was used, in a 13 x 5 factorial scheme, consisting of thirteen storage times (0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44 and 48 h) and five compositions for the spray solution (B. bassiana, B. bassiana + Helper Neutrum, B. bassiana + TA-35, B. bassiana + Nimbus and B. bassiana + Orobor). The biological spray solution containing B. bassiana conidia and no adjuvants remained viable for use after preparation and the conidial germination decreased 9.2 times after 48 h when an adjuvant was added.

Parâmetros técnicos da tecnologia de aplicação aplicados à pulverização hidropneumática em diferentes condições operacionais

Brazil is the largest producer and exporter of coffee in the world, and has been facing difficulties due to the cultivar’s susceptibility to the occurrence of insects. This study aimed to evaluate the application parameters using the hydro pneumatic sprayer with different volumes of spray mix and sprayer nozzles, in the presence and in the absence of agricultural adjuvants. The work was carried out in an experimental area in the city of Monte Carmelo / MG, with the evaluation of the hydro pneumatic application efficiency with different volumes of spray mix, 200 and 400 L ha-1, two empty cone sprayer nozzles (JA-01 and TVI -800075), presence / absence of agricultural adjuvant in the application spray mix, Cartape Hydrochloride 500 g i.a ha-1, Cartape Hydrochloride (500 g i.a ha-1) + orange oil at a dose of 75 mL 100 L-1 of syrup. The use of orange oil interfered in parameters of droplet size and relative amplitude. The use of coarse droplets is a viable alternative for the application efficiency in low air humidity times. The higher volume of spray mix resulted in an increase in percentage of coverage and size of droplets.

Agricultural adjuvants market to grow owing to rising need for precision farming

Agricultural adjuvants market to grow owing to rising need for precision farming

Agricultural adjuvants may impair leaf transpiration and photosynthetic activity

Adjuvants such as surfactants are commonly incorporated into agrochemical formulations to enhance the biological efficiency of foliar sprays by improving the wetting behavior of the spray and/or the penetration of the active ingredients into the leaf tissues. Penetration accelerating adjuvants are known to increase the cuticular permeability and may alter the cuticular barrier to water loss. However, none or very little emphasis has been given to the impacts of adjuvants on crop water balance or drought tolerance, a very important factor affecting crop performance under water scarcity. Two model crops with strongly varying leaf traits, kohlrabi (Brassica oleracea) and apple (Malus domestica) seedlings were grown in controlled environments. Three adjuvants with varying solubility in the cuticle, i.e. octanol-water partition coefficients (logKow) were selected: rapeseed methyl ester (RME) and the surfactants alkyl polyglycoside (APG) and polyoxyethylated tallow amine (POEA). The higher the logKow of the adjuvant, the stronger was the increase of minimum epidermal conductance (gmin, an essential parameter describing plant drought tolerance). However, such effects depended on the physio-chemical properties of the leaf surface. In comparison to kohlrabi, the adjuvant effects on gmin of apple leaves were relatively weak. The increase of gmin was associated with a decrease in contact angle and with an alteration of the wax microstructure. Furthermore, POEA affected photochemical efficiency of kohlrabi leaves. Some adjuvants could have a temporal influence on transpirational water loss and gmin. At repeated applications, they might alter the effective water use and possibly reduce drought tolerance of some horticultural crops.

Agricultural adjuvants market worth $4.04 bn by 2023

Agricultural adjuvants market worth $4.04 bn by 2023

Mobility of a Polyether Trisiloxane Surfactant in Soil: Soil/Water Distribution Coefficients and Leaching in a Soil Column

Polyether trisiloxane surfactants are widespread used as agricultural adjuvants because they increase the activity and the rainfastness of pesticides. On the contrary to pesticides, the environmental fate of agricultural adjuvants has not been much investigated, yet. Especially for trisiloxane surfactants, the knowledge on their environmental fate is scarce. To fill this gap, the mobility of a polyether trisiloxane surfactant on soil was studied. With a sorption batch equilibrium method, distribution coefficients between water and soil (Kd, Koc, and Kclay) were estimated for two standard soils (loam and sandy loam) and for every homologue of the trisiloxane surfactant. The obtained values for Kd were between 15 and 135 cm3 g−1, indicating that the trisiloxane surfactant is only slightly mobile in soil. The leaching in soil column was studied in a worst case scenario where the application of the trisiloxane surfactant was done on quartz sand and was immediately followed by a heavy rainfall. Less than 0.01 % of the initially applied trisiloxane surfactant had leached through 20 cm of quartz sand. Based on the Kd values and the leaching in a soil column, the studied trisiloxane surfactant seems to be unlikely to leach through soil after application as agricultural adjuvant.

The Influence of the Water Quality on the Droplet Spectrum Produced by Agricultural Nozzles

Abstract The aim of the studies was to check if the quality of water, which was taken from different sources, to plant protection treatments influences the change of the droplet size generated by an agricultural nozzle. For the study water taken from 3 different sources was used and demineralized water was used as a reference. The water quality was evaluated as far as its hardness was concerned. Water hardness was measured with a droplet test. One of the most frequently used by farmers type of agricultural nozzle TeeJet VP of the size 110/02 was used in the study. The study was performed in two combinations. One of them was carried out for the pure water and the second one for water with addition of agricultural spray adjuvant Superam 10AL. The measurements were done with three pressure values: 2 bar, 3 bar and 4 bar in three repetitions. The droplet size was measured with a laser diffractometer HELOS/R by Sympatec. The study showed that water hardness did not have any significant influence on the droplet size formed by agricultural nozzles. Adding of agricultural spray adjuvant to the water did not cause any significant change in the droplet size, however, the difference in water hardness caused the decrease of a diameter of formed droplets. The results were compared in a tabular and graphic form. In the next phase of the study for individual types of waters agricultural spray adjuvant was added to check how it influences the change of the size of droplets produced by the nozzles with sliding pressure in the whole range of the stream sprayed by the nozzle.

The Effects of Polyethylene Glycol (PEG-600) On the Acute Neurotoxicity of Different Types of Pesticides

Pesticides intoxication has been implicated in many toxic diseases, and agricultural adjuvants including polyethylene glycols are used in a variety of applications including industrial manufacturing. The aim of this study was to analyze the effect of PEG-600 on the biochemical toxic effects of malathion, imiprothrin and imidacloprid on the basis of the determined LD50 values on the quails (Coturnix coturnix). In the present study the toxic effect of the tested pesticides was characterized by a clear disturbances in the activity ofplasma alkaline phosphatase (ALP), transaminases (AST, ALT), acetylcholinesterase ( AChE) and total contents , as well the concentrations of brain glutamate, aspartate, GABA, glycine, norepinephrine and dopamine concentrations. PEG-600 treatment did not change blood biochemical parameters but significantly increases the concentrations of whole brain studied amino acids and catecholamines In addition, the combination of PEG-600 with the tested pesticides acts synergistically on reducing the recorded LD50 values of malathion, imidacloprid and imiprothin in Coturnix coturnix by -32.247, -41.529 and -11.026 ; attenuates more toxic symptoms, modulates more changes in the activity of plasma AChE, ALP ,AST, and ALT and attenuates more decreased effect in the concentration of the brain dopamine and norepinephrine, and potentiate more toxic effects of the studied pesticides on the concentration of the free studied amino acids. .These results could indicate the toxic effect of polyethylene glycol to birds and is also potentiate the neuronal toxic effect of pesticides exposure.

The study of the molecular ecology of bacteria involved in a life cycle impact assessment of agricultural adjuvants

The study of the molecular ecology of bacteria involved in a life cycle impact assessment of agricultural adjuvants

The study of the molecular ecology of bacteria involved in a life cycle impact assessment of agricultural adjuvants<sup>#</sup>

The study of the molecular ecology of bacteria involved in a life cycle impact assessment of agricultural adjuvants<sup>#</sup>

Toxicity Ranking and Toxic Mode of Action Evaluation of Commonly Used Agricultural Adjuvants on the Basis of Bacterial Gene Expression Profiles

The omnipresent group of pesticide adjuvants are often referred to as “inert” ingredients, a rather misleading term since consumers associate this term with “safe”. The upcoming new EU regulation concerning the introduction of plant protection products on the market (EC1107/2009) includes for the first time the demand for information on the possible negative effects of not only the active ingredients but also the used adjuvants. This new regulation requires basic toxicological information that allows decisions on the use/ban or preference of use of available adjuvants. In this study we obtained toxicological relevant information through a multiple endpoint reporter assay for a broad selection of commonly used adjuvants including several solvents (e.g. isophorone) and non-ionic surfactants (e.g. ethoxylated alcohols). The used assay allows the toxicity screening in a mechanistic way, with direct measurement of specific toxicological responses (e.g. oxidative stress, DNA damage, membrane damage and general cell lesions). The results show that the selected solvents are less toxic than the surfactants, suggesting that solvents may have a preference of use, but further research on more compounds is needed to confirm this observation. The gene expression profiles of the selected surfactants reveal that a phenol (ethoxylated tristyrylphenol) and an organosilicone surfactant (ethoxylated trisiloxane) show little or no inductions at EC20 concentrations, making them preferred surfactants for use in different applications. The organosilicone surfactant shows little or no toxicity and good adjuvant properties. However, this study also illustrates possible genotoxicity (induction of the bacterial SOS response) for several surfactants (POEA, AE, tri-EO, EO FA and EO NP) and one solvent (gamma-butyrolactone). Although the number of compounds that were evaluated is rather limited (13), the results show that the used reporter assay is a promising tool to rank commonly used agricultural adjuvants based on toxicity and toxic mode of action data.

Population-level toxicity of the insecticide, spinosad and the nonylphenol polyethoxylate, R-11, to the cladoceran species Ceriodaphnia dubia Richard

The effects of the natural insecticide, spinosad, and the agricultural adjuvant, R-11, were evaluated on populations of the water flea, Ceriodaphnia dubia after chronic 8-day exposures. The number of individuals used to start the chronic exposure studies (founders) and the number of offspring/surviving female were significantly reduced after exposure to spinosad concentrations ⩾ 2.5 μg/L. The final number of individuals was significantly reduced after exposure to spinosad concentrations ⩾ 1.0 μg/L. Population growth rate was significantly reduced after exposure to spinosad concentrations ⩾ 1 μg/L. Extinction occurred (defined as negative population growth rate) after exposure to spinosad concentrations of 10 μg/L. Therefore, negative effects were observed in C. dubia after exposure to spinosad at a concentration near the chronic expected environmental concentration (EEC) of 2.3 μg/L. R-11 was much less toxic to C. dubia than spinosad. The number of founders was not significantly reduced until C. dubia were exposed to 12,000 μg/L. The number of offspring/surviving female, final number of individuals, and population growth rate were significantly reduced after exposure to R-11 concentrations ⩾ 5,000 μg/L. Extinction occurred after exposure to R-11 concentrations of 12,000 μg/L which was above the EEC of 790 μg/L. These results indicate that spinosad and R-11 both have lethal and sublethal effects on C. dubia. However, spinosad appears to affect C. dubia at or near the EEC while R-11 does not negatively affect this species until concentrations are much higher than the EEC.