Tank-mix Adjuvants Research Articles

Tank-Mix Adjuvants Enhance Pesticide Efficacy by Improving Physicochemical Properties and Spraying Characteristics for Application to Cotton with Unmanned Aerial Vehicles.

Tank-mix adjuvants have been used to reduce spray drift and facilitate the efficacy of pesticides applied with unmanned aerial vehicles (UAVs). However, the effects of specific adjuvants on pesticide characteristics and the mechanism of action remain unclear. Herein, we analyzed the effects of three different types of tank-mix adjuvants (plant oil; mineral oil; and mixture of alcohol and ester) on the surface tension (ST), contact angle, wetting, permeation, evaporation, spray performance, and aphid-control effects of two types of pesticides. The mineral oil adjuvant Weichi (WCH) was highly effective in reducing the pesticide solution ST, improving the wetting and penetration ability, increasing droplet size, and promoting droplet deposition. The mixed alcohol and ester adjuvant Quanrun (QR) showed excellent wetting and antievaporation properties and promoted droplet deposition. A plant oil adjuvant (Beidatong) moderately improved wetting and penetration ability and reduced droplet drift. Field tests showed that the control efficiencies (CEs) of two pesticides were increased after the addition of adjuvants, even with 20% reductions in pesticide application. When the UAV was operated at 1.5 m, the CEs of two pesticides were increased from 65.39 and 66.63% to 73.11-76.52% and 77.91-88.31%, respectively. When operated at 2.5 m, the CEs were increased from 51.24 and 68.60% to 65.06-75.70% and 77.57-92.59%, respectively. Especially, the CEs of pesticides with WCH and QR increased obviously. Importantly, neither WCH nor QR inhibited hatching of the critical insect natural enemy ladybird beetle at concentrations used in the field. This study provides a framework for assessment of tank-mix adjuvants in aerial sprays and directly demonstrates the value of specific adjuvants in improving pesticide bioavailability and minimizing associated environmental pollution.

Tank-mix adjuvants improved spray performance and biological efficacy in rice insecticide application with unmanned aerial vehicle sprayer.

The use of unmanned aerial vehicles (UAVs) for the application of plant protection products (PPPs) in paddy fields is becoming increasingly prevalent worldwide. Despite its growing usage, UAV spraying for rice pest control faces practical challenges, including limited canopy penetration, uneven deposition, and significant spray drift. This study investigated the impact of two tank-mix adjuvants, Wonderful Rosin (Adjuvant-1) and Tiandun (Adjuvant-2), at six volume concentrations, on the spray liquid's physicochemical properties, spray drift, plant deposition, and the biological efficacy of rice insecticides using a quadrotor UAV sprayer. The physicochemical characteristics of the spray liquid influenced spray performance and biological efficacy. Incorporating Adjuvant-1 and Adjuvant-2 led to a decrease in surface tension and contact angle while increasing the viscosity of the spray solution. These alterations in surface tension and viscosity contributed to an optimized droplet size distribution, reduced spray drift, enhanced deposition uniformity and penetration, and improved control efficacy against the rice planthopper in UAV applications. The highest control efficacy was observed at a concentration of 0.5%, showing an improvement of 35.12% (Adjuvant-1) and 20.23% (Adjuvant-2) over applications without tank-mix adjuvant 7 days after treatment. The judicious selection of tank-mix adjuvants for UAV PPP applications can significantly enhance spray performance and biological efficacy in controlling rice insects. This study's findings offer valuable insights for integrating tank-mix adjuvants into UAV spraying applications. © 2024 Society of Chemical Industry.

Synergistic mechanism and environmental behavior of tank-mix adjuvants to topramezone and atrazine.

An effective way to reduce herbicide quantity is to use adjuvants in order to optimize the amount of herbicide and improve its control efficiency. In order to screen for efficient herbicide tank-mix adjuvants, improve the control of weeds in maize fields, reduce the amount of effective ingredients, and improve the adsorption and digestion behavior of herbicides in soil, this study evaluated the synergistic effects and soil behavior of four types of tank-mix adjuvants combined with herbicides. Different types of adjuvants can enhance herbicide production. Surface tension was significantly reduced by 13% after the pesticide solution was applied with AgroSpred™ Prime. The contact angle with the foliar surface was significantly reduced and solution wettability improved using Atp Lus 245-LQ-(TH). The permeability of topramezone and atrazine in leaves of Amaranthus retroflexus L. and Digitaria sanguinalis (L.) Scop. was increased by 22-96% after adding either tank-mix adjuvant. The solution drying time and maximum retention on leaves were not affected by the tank-mix adjuvants. Ethyl and methylated vegetable oils can reduce the adsorption of topramezone in the soil, thus reducing its half-life in soil. The tank-mix adjuvants had no significant effect on soil dissipation or adsorption of atrazine. AgroSpred™ Prime and Atp Lus 245-LQ-(TH) have the best synergistic effect on topramezone and atrazine in the control of A. retroflexus L. and D. sanguinalis (L.) Scop. in maize fields.

Enhanced dosage delivery of pesticide under unmanned aerial vehicle condition for peanut plant protection: tank-mix adjuvants and formulation improvement.

Suspension concentrate (SC) is one of the most widely used formulations for agricultural plant protection. With the rapid development of unmanned aerial vehicle (UAV) plant protection, the problems of spray drift, droplet rebound and poor wettability in the application of SC from UAVs have attracted wide attention. Although some tank-mix adjuvants have been used to enhance dosage delivery for UAV, their effects and mechanisms are not fully clear, and few formulations are specifically designed for UAV. The type and concentration of tank-mix adjuvant affect the dosage delivery of SC. MO501 can significantly reduce DV<100μm , and inhibit droplet rebound on peanut leaves at concentrations ≥0.5%. Silwet 408 can achieve complete wetting and superspreading after adding ≥0.2% concentrations, but only ≥0.5% can inhibit rebound. XL-70 shows excellent regulation ability even at low concentration, and 0.2% concentration can simultaneously suppress impact and promote spreading. Besides, the formulation oil dispersion (OD) can significantly reduce the driftable fine fraction and inhibit rebound at dilution ratios of ≤250-fold, thus enhancing dosage delivery. SC is prone to rebound on hydrophobic leaf surfaces and shows poor wetting and spreading properties. Appropriate types and concentrations of tank-mix adjuvants and formulation improvement are two effective strategies for improving the dosage delivery of pesticides, whereas the addition of inappropriate adjuvants may cause potential risks instead. These findings provide guidance for the rational selection of tank-mix adjuvants and potential applications of OD for UAV plant protection. © 2023 Society of Chemical Industry.

How tank-mix adjuvant type and concentration influence the contact angle on wheat leaf surface.

Currently, the utilization of unmanned aerial vehicles (UAVs) for spraying pesticides is a prevalent issue in Asian countries. Improving the pesticide efficiency of UAV spraying is a major challenge for researchers. One of the factors that affect the efficiency is the wetting property of the spraying solutions on crop leaves. Tank-mix adjuvants, which can modify the wetting ability of the solutions, are often used for foliar application. However, different types and concentrations of tank-mix adjuvants may have different impacts on the wetting properties of droplets. In this article, we investigated the effects of four tank-mix adjuvants, Beidatong (BDT), Velezia Pro (VP), Nongjianfei (NJF), and Lieying (LY), on the dynamic contact angle (CA) values of droplets on the adaxial surface of wheat leaves. We measured the dynamic CA values of various concentrations of each adjuvant solution and determined the optimal concentrations based on the CA values, droplet spreading time, and cost. The results showed that adding any of the four adjuvants decreased the CA values, but the patterns of decrease varied among them. The CAs of BDT and VP solutions decreased slowly during the observation time (0-8.13 s), while those of NJF and LY solutions decreased rapidly throughout the observation period. According to the dynamic CA values of different concentrations, the optimal concentrations of BDT, VP, NJF, and LY for wheat field application were 12%, 16%, 6‰, and 0.3‰, respectively. Alkoxy-modified polytrisiloxane adjuvant (LY) could be recommended as an appropriate tank-mix adjuvant for wheat field application, considering spreading efficiency and cost. This study provides theoretical and practical guidance for selecting and optimizing tank-mix adjuvants for UAV spraying.

Effects of pesticide-adjuvant combinations used in almond orchards on olfactory responses to social signals in honey bees (Apis mellifera)

Exposure to agrochemical sprays containing pesticides and tank-mix adjuvants has been implicated in post-bloom mortality, particularly of brood, in honey bee colonies brought into California almond orchards for pollination. Although adjuvants are generally considered to be biologically inert, some adjuvants have exhibited toxicity and sublethal effects, including decreasing survival rates of next-generation queens. Honey bees have a highly developed olfactory system to detect and discriminate among social signals. To investigate the impact of pesticide-adjuvant combinations on honey bee signal perception, we performed electroantennography assays to assess alterations in their olfactory responsiveness to the brood ester pheromone (BEP), the volatile larval pheromone β-ocimene, and the alarm pheromone 2-heptanone. These assays aimed to uncover potential mechanisms underlying changes in social behaviors and reduced brood survival after pesticide exposure. We found that combining the adjuvant Dyne-Amic with the fungicide Tilt (propiconazole) and the insecticide Altacor (chlorantraniliprole) synergistically enhanced olfactory responses to three concentrations of BEP and as well exerted dampening and compensatory effects on responses to 2-heptanone and β-ocimene, respectively. In contrast, exposure to adjuvant alone or the combination of fungicide and insecticide had no effect on olfactory responses to BEP at most concentrations but altered responses to β-ocimene and 2-heptanone. Exposure to Dyne-Amic, Altacor, and Tilt increased BEP signal amplitude, indicating potential changes in olfactory receptor sensitivity or sensilla permeability to odorants. Given that, in a previous study, next-generation queens raised by nurses exposed to the same treated pollen experienced reduced survival, these new findings highlight the potential disruption of social signaling in honey bees and its implications for colony reproductive success.

Efficacy of Two Tank-Mix Adjuvants to Control Mango Thrips Using a UAV Sprayer

Thrips have become some of the most challenging pests to control in mango production due to their short developmental time, hidden locations and resistance to pesticides, in the tropical regions of China. To improve pesticides efficacy, the tank-mix adjuvants Qi Gong (QG) and the thrips attractant Lv Dian (LD) were added when using an unmanned aerial vehicle (UAV) to control thrips. The surface tension, contact angle on mango leaves, droplet size, spreading rate, and drying time of the two tank-mix adjuvants were determined. The effects of the two tank-mix adjuvants using a UAV sprayer on the droplet coverage and control efficacy against thrips on mango inflorescences were tested through field trials. The results showed that both QG and LD could reduce the surface tension of the liquid and the contact angle on mango leaves and could increase the spreading performance. The droplet coverage in the upper layer of the canopy was about 2% higher than that in the lower layer, and the coverage at the top of the panicle was 5% higher than that at the bottom. QG improved the deposition coverage of mango inflorescences by about 31.5%. The addition of QG increased the efficacy by 18.24% and 8.03%, respectively, at florescence and the young fruit stage. The addition of the LD increased the efficacy by 24.56% and 14.38%, respectively, at florescence and the young fruit stage. These test results can provide a scientific basis for the control of mango thrips with UAVs.

Combined Application of Tank-mix Adjuvants, Mist Sprayer and Nano-selenium Promoted Pesticide Reduction and Enhanced Strawberry Quality.

In this paper, several technologies suitable for strawberry crops, such as armyworm boards, tank-mix adjuvants, mist sprayers combined with pesticide reduction, and biostimulant nano-selenium, were comprehensively applied and evaluated. The combined use of 60% etoxazole and bifenazate, bucket mixing additives, nano-selenium, and mist sprayers achieved an 86% prevention effect on red spiders. The prevention effect of pesticides according to the recommended dosage was 91%. Similarly, the disease index of strawberry powdery mildew in the green control group (60% carbendazim, bucket mixing additives, nano-selenium, and mist sprayer) decreased from 33.16 to 11.11, with a decrease of 22.05. The disease index of the control group decreased from 29.69 to 8.06, with a decrease of 21.63. Additionally, the combination of pesticide reduction and nano-selenium significantly improved the antioxidant activity and soluble sugar level of strawberry fruit and reduced water loss during storage. Therefore, the integrated application of green control technologies is beneficial for reducing the amount of chemical pesticides and improving their effectiveness, while enhancing the quality of strawberry fruits in disease and pest control.

Effect of tank-mixed adjuvant on the behavior of chlorantraniliprole and difenoconazole in soil

In this study, both laboratory and field studies were performed to analyze the effect of the presence of tank-mixed methylated plant oil adjuvant on the adsorption and degradation of chlorantraniliprole (CAP) and difenoconazole (DIF) in soil. Adsorption kinetics and isotherms experiments were conducted according to the equilibrium oscillation method. Fourier transform infrared spectroscopy (FT-IR) analysis, soil contact angle, and zeta potential were used to research the interaction mechanism of adsorption. Fluorescence excitation emission matrix (FEEM) measurements were conducted to characterize soil dissolved organic matter. Field experiment was conducted to investigate the degradation of CAP and DIF combined with adjuvant. DIF exhibited a significantly higher Freundlich maximum adsorption capacity than CAP, which is consistent with the higher octanol–water partition coefficient of DIF. The sorption of CAP and DIF under laboratory conditions was significantly increased with the presence of adjuvant. Soils with high humic acids have strong adsorption capacity and contribute to significant adsorption of CAP and DIF. The half-lives of CAP and DIF tested in fluvo-aquic soil under field conditions were slightly reduced by the adjuvant. Adjuvant reduced the Groundwater Ubiquity Score (GUS) indices of CAP from 1.51 to 1.31, whereas that of DIF from 0.39 to 0.25. Combination between the pesticides and soil molecules can be enhanced, thereby promoting the adsorption and degradation of CAP and DIF in soil, and further reducing their potential to leach into groundwater when 0.1% methylated plant oil adjuvant was mixed and applied.

Machine Learning to Predict the Interfacial Behavior of Pesticide Droplets on Hydrophobic Surfaces for Minimizing Environmental Risk

Achieving accurate and efficient target deposition of pesticide droplets is the principal factor in minimizing environmental risk. For hydrophobic surfaces, adding tank-mix adjuvants containing surfactants to modulate interfacial behavior is warranted, which lacks common laws to guide practical applications directly. Machine learning is developing rapidly and makes many data-based decisions in various industrial processes. Hence, according to machine learning-based analysis of fundamental physical quantities, proposing quantitative sustainability metrics to improve interface behavior is essential. Comparing the interfacial behavior of five adjuvants, the common denominator is that droplets in the Wenzel state with higher adhesion tension and lower contact angles can generate the pinning force that causes energy dissipation, reduces pesticide losses, and weakens environmental pollution. Simultaneously, the interfacial behavior of pesticide droplets including adjuvants on citrus leaves is verified, while the phytotoxicity experiment under high temperature and the laboratory bioassay are carried out. The results show that the eco-friendly alkyl polyglycoside (APG) as the glycosidic surfactant has nontarget biosafety and better mite control, which can be exploited as a commercial tank-mix adjuvant for promotion. This study provides a new insight into guiding adjuvants added to pesticides on account of quantitative sustainability metrics, which has important implications for food safety and agricultural green development.

Tank-Mix Adjuvants Regulate the Deposition, Absorption, and Permeation Behavior of Pesticide Solutions on Rice Plant

Pesticide foliage treatment is used in agricultural production to protect plants from diseases, pests, or weeds. Tank-mix adjuvants added to the barrel can improve the effective utilization rate of pesticides. Herein, a comparative study was conducted to investigate the effect of three kinds of tank-mix adjuvant on the deposition, absorption, and permeation behavior of epoxiconazole and chlorantraniliprole solutions. Surface tension and contact angle results indicate that polyether-modified trisiloxane may be the best surface-active agent for pesticides, whereas methyl oleate and green-peel orange essential oil were found to be more suitable for improving pesticide deposition, absorption, and permeation in some cases. These findings indicate that various tank-mix adjuvants had different effects on pesticide application on plants. Appropriate tank-mix adjuvants need to be selected for comprehensive practical application.

Using tank-mix adjuvant improves the physicochemical properties and dosage delivery to reduce the use of pesticides in unmanned aerial vehicles for plant protection in wheat.

Unmanned aerial vehicles (UAVs) are widely used to improve the efficiency of pesticide applications. Low-volume spraying operations require more efficient deposition of droplets on the target surface. Therefore, pesticide deposition and retention on plant surfaces is a serious challenge for modern precision agriculture. Tank-mix adjuvants have been used to improve spray dilutions performance; however, their effects on the physicochemical properties of spray dilutions, dosage delivery, and pesticide dosage are unclear. Tank-mix adjuvant 8860 significantly improved the physicochemical properties of spray dilutions, inhibited spray droplets rebound, improved the wetting and spreading performance of spray dilutions on wheat leaves, and increased the effective deposition of tebuconazole on wheat leaves. Even when its dosage was reduced by one-third, the spray solution still showed excellent disease control and effective deposition of the active ingredient on wheat leaves. The use of appropriate tank-mix adjuvants in UAV-based plant protection for wheat can significantly improve the performance of spray dilutions, increase the efficiency of pesticide dosage delivery, and improve disease control. These adjuvants can also help reduce the pesticide use while ensuring their effectiveness. © 2022 Society of Chemical Industry.

UAV spraying on citrus crop: impact of tank-mix adjuvant on the contact angle and droplet distribution.

Adding tank-mix adjuvants into the spray mixture is a common practice to improve droplet distribution for field crops (e.g., rice, wheat, corn, etc.) when using Unmanned Aerial Vehicle (UAV) sprayers. However, the effectiveness of tank-mix adjuvant for UAV spraying in orchard crops is still an open problem, considering their special canopy structure and leaf features. This study aims to evaluate the effects of a typical tank-mix adjuvant concentrations (i.e., Nong Jian Fei (NJF)) on Contact Angle (CA) and droplet distribution in the citrus tree canopy. Three commonly used parameters, namely dynamic CA, droplet coverage, and Volume Median Diameter (VMD), are adopted for performance evaluation. The dynamic CAs on the adaxial surface of citrus leaves, for water-only and NJF-presence sprays, respectively, are measured with five concentration levels, where three replications are performed for each concentration. The sprays with 0.5‰ NJF are adopted in the field experiment for evaluating droplet distributions, where Water Sensitive Papers (WSPs) are used as collectors. Two multi-rotor UAVs (DJI T20 and T30) which consist of different sizes of pesticide tanks and rotor diameters are used as the spraying platforms. Both water-only and NJF-presence treatments are conducted for the two UAVs, respectively. The results of the CA experiment show that NJF addition can significantly reduce the CAs of the sprays. The sprays with 0.5‰ NJF obtain the lowest CA within the observing time, suggesting a better spread ability on solid surface (e.g., WSPs or/and leaves). With respect to the effects of NJF addition on individual UAVs, the field trial results indicate that NJF addition can remarkably increase both the droplet coverage and VMD at three canopy layers, except for T30 droplet coverage of the inside and bottom layers. Comparing the difference of droplet coverage between two UAVs, while significant difference is found in the same layer before NJF addition, there is no notable difference appearing in the outside and bottom layers after NJF addition. The difference of VMD in the same layer between two UAVs is not affected by NJF addition except for the bottom layer. These results imply that the differences of droplet coverage among different UAVs might be mitigated, thus the droplet distribution of some UAVs could be improved by adding a tank-mix adjuvant into the sprays. This hypothesis is verified by investigating the droplet penetration and the correlation coefficient (CC) of droplet coverage and VMD. After NJF addition, the total percentage of T20 droplet coverage in the bottom and inside layers is increased by 5%. For both UAVs, the CCs indicate that both droplet coverage and VMD increase at the same time in most cases after NJF addition. In conclusion, the addition of a tank-mix adjuvant with the ability to reduce CA of the sprays, can effectively improve droplet distribution using UAV spraying in the citrus canopy by increasing droplet coverage and VMD.

Effects of tank-mix adjuvants on physicochemical properties and dosage delivery at low dilution ratios for unmanned aerial vehicle application in paddy fields.

Unmanned aerial vehicles (UAVs) have been developed to improve the efficiency of pesticide applications, and they are now widely utilized in Asia. The deposition and retention periods of pesticides on plant surfaces present serious challenges for modern precision agriculture, as these factors directly affect pesticide bioavailability, efficacy, and loss. Tank-mix adjuvants have been utilized to improve pesticide performance, but their effects on physicochemical properties and dosage delivery at low dilutions are not well understood. We found that different tank-mix adjuvants affected droplet impact behavior, the wetting and spreading of spray dilutions, and pesticide deposition on rice leaves by changing the physicochemical properties of spray dilutions. The adjuvant methyl oxirane polymer with oxirane, mono (3,5,5-trimethylhexyl) ether (adjuvant c) significantly reduced the dynamic surface tension of the spray dilution and inhibited the rebound of large droplets (D0 =2 ± 0.2 mm) and spray droplets (0.2MPa with a LU-01 nozzle) on rice leaves, and improved the wetting and spreading performance of the spray dilution on rice leaves. Field tests showed that adjuvant c could significantly increase the deposition of chlorantraniliprole on rice leaves. Overall, the use of appropriate tank-mix adjuvants at low dilution ratios for UAV application in paddy fields can improve the performance of spray dilutions, increase the effective deposition and wetting spread of pesticides on rice leaves, further reduce the dosage of pesticide products and improve pesticide utilization. © 2022 Society of Chemical Industry.

Effects of Adjuvants on Spraying Characteristics and Control Efficacy in Unmanned Aerial Application

Pesticide application by unmanned agricultural aerial vehicles (UAVs) has rapidly developed in China and other Asian counties. Currently, tank-mix spray adjuvants are usually added into pesticide solutions to reduce spray drift and facilitate droplet deposition and control efficacy. The currently used tank-mix adjuvants are all derived from conventional ground sprays, and their mechanisms of action in aerial applications are still unclear. In order to clarify the spraying characteristics and control efficacy of those adjuvants in aerial sprays, the performances of various types of tank-mix adjuvants were compared by analyzing droplet spectrum, drift potential index (DIX) in a wind tunnel, field deposition and control efficacy on wheat rust and aphids. The atomization results showed that the addition of adjuvants could change the droplet spectrum of liquid, and the results suggest that droplet size is an effective indicator of spray drift potential. In the field application, the meteorological conditions are complex and uncontrollable, and the effects of adjuvants on droplet deposition and distribution were not significant. Compared with the control solution, there was no significant difference in the deposition amount of each adjuvant solution, and the CVs of deposition were higher than 30%. Adding adjuvants to the spray solution can significantly improve the control efficacy of pesticides on wheat aphids and rust and also prolong the duration of the pesticide. Our results suggest that tank-mix adjuvants should be added when UAVs are used for aerial application. This study can be used as a reference to the research and development or selection of adjuvants in aerial sprays of UAVs.

Tank-mix adjuvants to reduce the adverse effect of muddy rain on the activity of paraquat against winter wild oat

This study was designed to determine the adverse effect of soil settling on a weed through a simulated muddy rain on the activity of a bipyridylium herbicide and to compare the efficacy of three adjuvants to decrease this adverse effect. In a greenhouse experiment, a 0.04-mm muddy rain containing 0, 1, 2, 4 and 8 kg soil ha−1 was rained on winter wild oat before the doses of 0, 75, 150, 300, 600, and 1200 g paraquat ha−1 were sprayed on. In a companion experiment, a 0.04-mm muddy rain containing 0 and 8 kg soil ha−1 were rained on winter wild oat before the aforementioned doses of paraquat were sprayed with or without acriflavine chloride, chlormequat chloride, and mepiquat chloride at 0.2% (w/v). Based on the dose giving 90% dehydration of the plant, the muddy rain containing 1, 2, 4, and 8 kg soil ha−1 decreased the activity of paraquat against winter wild oat in run 1 by 1.2-, 1.6-, 2.5-, and 7.0-fold and in run 2 by 1.4-, 3.0-, and 6.4-fold in comparison with control, respectively. All adjuvants were effective in significantly decreasing the adverse effect of muddy rain on the activity of paraquat against winter wild oat. In this regard, chlormequat chloride was the most effective, following by acriflavine chloride and mepiquat chloride.

Surface tension and spreading coefficient of single-and mix-pesticide solutions with aerial spraying organosilicone adjuvant

Abstract: Recently, unmanned aerial vehicles (UAVs) have been widely used to spray pesticides to control diseases and pests of many crops. During the process of pesticide application by UAV spraying, aerial spraying tank-mix adjuvants are usually mixed with pesticide solution to improve the efficiency of pesticides. Preventing pesticides depositing in off-target area is important in enhancing pesticide utilization. Improving the wetting and spreading of pesticides is one of the most important ways to reduce pesticide droplets running off from the target. This study is focusing on the effects of aerial spraying tank-mix organosilicone adjuvant (OA) on surface tension and spreading coefficient of pesticide solutions. Six pesticide solutions used alone and mixed together of different concentrations are prepared under field application conditions. Surface tension and spreading coefficient of the solution with and without OA were measured, respectively. The results show that OA could significantly lower surface tension and increase spreading coefficient of pesticide solutions regardless of solution concentrations. OA with concentration higher than critical micelle concentration (CMC) could not further decrease surface tension, but still could significantly increase spreading coefficient of the solution. For solutions with single pesticide belongs to different formulations, the minimum needed concentration of OA is different due to formulation type. The minimum concentration of OA for solution of suspension concentrate and aqueous solution (0.5‰-0.7‰) is lower than that of solutions of emulsifiable concentrate (EC) (2.0‰-5.0‰). For solutions of several pesticides mixed together, the minimum concentration of OA is related to the number of EC formulation in the solution. For pesticide solutions containing one EC formulation, the minimum concentration of OA is 2.0‰; for pesticide solutions containing two or three EC formulation, the minimum concentration of OA is recommended to be 5.0‰-10.0‰. These results suggest that the concentration of OA needed for pesticide solution should be evaluated before field application considering pesticide belonging to different formulations mixing together for application. Keywords: aerial spraying adjuvant, organosilicone, surface tension, spreading coefficient DOI: 10.33440/j.ijpaa.20210401.159 Citation: Meng Y H, Wang M M, Wang Z G, Hu H Y, Ma Y. Surface tension and spreading coefficient of single-and mix-pesticide solutions with aerial spraying organosilicone adjuvant. Int J Precis Agric Aviat, 2021; 4(1): 6–13.

PP 1/291 (1) Evaluation of the influence of tank mix adjuvants on the efficacy of plant protection products

Specific scopeFor countries with national requirements for efficacy data to support claims on adjuvants marketed for use with plant protection products this Standard provides advice on how to generate the data. It may also be of use to manufacturers of adjuvants during development of their products and to manufacturers of plant protection products to support label claims. Differentiation is made between voluntary recommendations and requirements of mandatory mixtures on label claims of plant protection products, as this latter case should be considered as a plant protection product use covered by the relevant EPPO Standards (PP 1).Specific approval and amendmentFirst approved in 2016‐09

Two tank-mix adjuvants effect on yield and quality attributes of wheat treated with growth retardants

ABSTRACT: The objective of this study was to evaluate the quality of seeds and yield of winter wheat under different retardants application. The two years field trials on winter wheat were carried out in the Institute of Plant Protection - National Research Institute in Poznan (Poland). Treatments consisted of trinexapac-ethyl, chlormequat and prohexadione calcium applied in mixtures with paraffin oil adjuvant or organosilicone surfactant in BBCH 31 growth stage of winter wheat. No lodging occurred in any experimental year. The retardants had varying effect on the quality parameters of wheat grain. The highest fluctuations in the content of protein, gluten and the Zeleny value were observed after the application of chlormequat chloride. Starch content in wheat grain, regardless of the retardant application method, was negatively correlated with others grain quality parameters evaluated in the experiment. Depending on the year of study and weather conditions, increased or decreased wheat quality.

Impact of tank-mix adjuvants on deposit formation, cuticular penetration and rain-induced removal of chlorantraniliprole

Off-target deposits of agrochemicals impose a general risk for the environment while environmental factors such as rainfall might cause significant pesticide removal from agricultural crops and contribute to a requirement for a higher rate and frequency of applications in intensive agricultural systems. In the present study, we analyzed the impact of five tank-mix adjuvants (three organosilicones – one superspreader, one penetrating agent and one spreader-sticker – as well as one paraffinic oil and one vegetable oil with non-ionic surfactants) on the amount of active ingredient (AI) deposited, deposit characteristics at the microscale, and rain-induced removal of chlorantraniliprole from the hydrophobic leaf surfaces of wheat and maize. In addition, the cuticular penetration of the AI was determined on astomatous cuticles from the adaxial side of apple leaves. The tank-mix adjuvants with lower surface tension (organosilicone superspreader and organosilicone-based penetrating agent) caused a lower contact angle of sessile droplets, larger surface coverage, and higher AI amount on wheat and maize leaves. Heavy rain (5 mm h−1) removed zero to 60% of the chlorantraniliprole from wheat leaves, and 20–60% from maize leaves, the losses being more pronounced in those treatments with higher initial AI amount. Moreover, in wheat we observed a pronounced effect of the rain amount (5 mm or 10 mm) on the AI removal. Environmental scanning electron micrographs indicated the rain-induced displacement of the AI and adjuvants and their partial re-allocation within the droplet footprint. Moreover, the micrographs showed no residues in adjacent areas outside the primary droplet footprint. Cuticular penetration of chlorantraniliprole, which was demonstrated here for the first time, ranged from 15 to 30%, but no statistical differences (p ≤ 0.05) were found between the experimental groups. In summary, the evaluated tank-mix adjuvants positively influenced the AI amount and deposit formation of chlorantraniliprole on hydrophobic leaves. In the case of rain, the add-on value of adjuvants on retention and AI amount might be partially lost, since the highest wash-off was associated with the highest deposition; nevertheless, the AI concentration on the leaves after rain remained significantly higher, or in worst-case similar to, the control group. In specific cases, the cuticular penetration might be improved, while no information on stomatal infiltration and bio-efficacy is provided. Finally, we point to the need for further optimization of adjuvant-AI systems to increase both penetration and rainfastness, and in this way constrain AI losses and unnecessary environmental contamination.