Controlled Release Pesticide Formulations Research Articles

Evaluation of Environment Exposure Potential of Atrazine Herbicide and Synthesis of Polymeric Controlled Release Pesticide Formulations

Evaluation of Environment Exposure Potential of Atrazine Herbicide and Synthesis of Polymeric Controlled Release Pesticide Formulations

Coprecipitation-based synchronous chlorantraniliprole encapsulation with chitosan: carrier-pesticide interactions and release behavior.

Controlled-release pesticide formulations have emerged as a promising approach towards sustainable pest control. Herein, an environment-friendly formulation of insecticide chlorantraniliprole (CAP) was fabricated through a simple approach of coprecipitation-based synchronous encapsulation by chitosan (CTS), with carrier-pesticide interaction mechanism and release behavior investigated. The resulting CAP/CTS controlled-release formulation (CCF) showed a good loading content of 28.1% and a high encapsulation efficiency of 75.6%. Instrument determination in combination with molecular dynamics (MD) simulations displayed that the primary interactions between CAP and CTS were physical adsorption and complicated hydrogen (H)-bonds, which formed dominantly between NH in amides [or nitrogen (N) in ring structures] of CAP and hydroxyl (or amino) groups of CTS, as well as oxygen (O) in CAP with hydrogen in CTS or H2 O molecules. The in vitro release tests exhibited obvious pH/temperature sensitivity, with release dynamics following the first-order or Ritger-Peppas model. As the temperature increased, the CAP release process of the Ritger-Peppas model changed from Case-II to anomalous transport, and ultimately to a Fickian diffusion mechanism. The control effect against Plutella xylostella larvae also was evaluated by toxicity tests, where comparable efficacy of CCF to the commercial suspension concentrate was obtained. The innovative, easy-to-prepare CCF can be used as a formulation with obvious pH/temperature sensitivity and good efficacy on target pests. This work contributes to the development of efficient and safe pesticide delivery systems, especially using the natural polymer materials as carriers. © 2023 Society of Chemical Industry.

Evaluation of a Spinosad Controlled-Release Formulation Based on Chitosan Carrier: Insecticidal Activity against Plutella xylostella (L.) Larvae and Dissipation Behavior in Soil.

Controlled-release pesticide formulations using natural polymers as carriers are highly desirable owing to their good biocompatibility, biodegradability, and improved pesticide utilization. In this study, the application potential of our previously prepared spinosad/chitosan controlled-release suspension (SCCS) was evaluated through both toxicity and dissipation tests. A comparison with the spinosad suspension concentrate and the commercial spinosad emulsion in water showed that the insecticidal activity of SCCS against Plutella xylostella larvae displayed the best quick-acting performance as well as long-term efficacy of more than 20 days. The 48 h LC50 for a 20-day efficacy was calculated to be 29.36 mg/L. The dissipation behavior of spinosad in the spinosad/chitosan microparticles in soil was found to follow the first-order kinetics, with a relatively shorter half-life (2.1 days) than that observed for the unformulated spinosad (3.1 days). This work showed the positive effect of chitosan on spinosad in improving insecticidal activity and reducing environmental risks in soil, which provided useful information on the application potential of pesticide–carrier systems based on natural polymer materials in crop protection and food safety.

Advances in Controlled-Release Pesticide Formulations with Improved Efficacy and Targetability.

Pesticides are commonly used in modern agriculture and are important for global food security. However, postapplication losses due to degradation, photolysis, evaporation, leaching, surface runoff, and other processes may substantially reduce their efficacy. Controlled-release formulations can achieve the permeation-regulated transfer of an active ingredient from a reservoir to a target surface. Thus, they can maintain an active ingredient at a predetermined concentration for a specified period. This can reduce degradation and dissipation and other losses and has the potential to improve efficacy. Recent developments in controlled-release technology have adapted the concepts of intelligence and precision from the pharmaceutical industry. In this review, we present recent advances in the development of controlled-release formulations and discuss details of the preparation methods, material improvements, and application technologies.

One-Pot Facile Synthesis of Double-Shelled Mesoporous Silica Microcapsules with an Improved Soft-Template Method for Sustainable Pest Management.

A controlled release formulation based on silica microcapsules is an ideal selection to improve both the effective utilization and duration of pesticides to decrease ecological damage. Herein, a simple and green method for preparing double-shelled microcapsules was developed using a newly prepared quaternary ammonium ionic liquid (IL) as the functional additive to entrap avermectin (Ave) in mesoporous silica nanospheres (MSNs) and tannic acid-Cu (TA-Cu) complex as the sealing agent to form the core-shell structure (Ave-IL@MSN@TA-Cu). The obtained microcapsules with an average size of 538 nm had pH-responsive release property and good stability in soil. The half-life of microcapsules (34.66 days) was 3 times that of Ave emulsifiable concentrate (EC) (11.55 days) in a test soil, which illustrated that microcapsules could protect Ave from rapid degradation by microorganisms by releasing TA, copper, and quaternary ammonium in the soil. Ave-IL@MSN@TA-Cu microcapsules had better nematicidal activity and antibacterial activity than Ave EC due to the synergistic effect of Ave, IL, and copper incorporated in the microcapsules. Pot experiments showed that the control efficacy of microcapsules was 87.10% against Meloidogyne incognita, which is better than that of Ave EC (41.94%) at the concentration of 1.0 mg/plant by the root-irrigation method after 60 days of treatment owing to the extended duration of Ave in microcapsules. The simple and green method for the preparation of double-shelled microcapsules based on natural quaternary ammonium IL would have tremendous potential for the extensive development of controlled release pesticide formulations.

A review on nanocomposites and their role in insecticide delivery

The extensive application of conventional chemical pesticides may result into several public health concerns as well as enviornmental hazards. To ensure food safety, use of alternative ecofriendly pesticide formulations is need of the hour. Nanocomposites, a special class of nanomaterials, having improved stability and barrier properties may be a viable option to develop environmentally benign slow/ controlled release pesticide formulations. Presently, the use of nanocomposites in preparation of insecticidal formulations is in early stage of research and development. Application of different nanocomposite materials as vector for chemical insecticides have been summarized in this review with major emphasis on application arenas in crop protection, along with addressing limitations and prospects of this domain.

A new temperature-responsive controlled-release pesticide formulation – poly(N-isopropylacrylamide) modified graphene oxide as the nanocarrier for lambda-cyhalothrin delivery and their application in pesticide transportation

In recent years, stimuli-responsive controlled-release pesticide formulations have drawn extensive as they show huge potential in the practical application of agriculture. Herein, a multifunctional composite nanocarrier was prepared by our group, Poly(N-isopropylacrylamide) modified graphene oxide (PNIPAm-GO), this is a temperature-responsive release pesticide formulation that can regulate pesticide release based on the temperature change. Lambda-cyhalothrin (LC) was loaded on PNIPAm-GO nanocomposite carrier via a simple physisorption process and LC@PNIPAm-GO exhibited temperature-responsive controlled release performance leading to release of LC at a specified temperature and extended its persisted release time. In addition, the LC@PNIPAm-GO controlled-release pesticide formulations showed both good water solubility and dispersion stability while its anti-UV property. Furthermore, we also assessed the biological safety of LC@PNIPAm-GO and proved that PNIPAm-GO is non-toxic. The study of this temperature-responsive pesticide formulation has promoted the development of intelligent pesticide formulations to great extent.

Use of bentonite and humic acid as modifying agents in alginate-based controlled-release formulations of imidacloprid

In order to prepare a formulation to be used for controlled release, imidacloprid was incorporated into alginate granules by using calcium chloride as gellant. The formulation prepared (alginate–imidacloprid–water) was modified by the addition of different sorbents. The effects on release rate of the addition of natural bentonite desiccated at 105 °C, untreated, acid-treated with sulfuric acid solutions over a concentration range between 0.5 mol dm−3 and 2.5 mol dm−3, and a commercial humic acid, were studied by immersion of the granules in water under static conditions. The time taken for 50% of the active ingredient to be released into water, (T50), was calculated from the data obtained. On the other hand, the sorption–desorption processes of imidacloprid from a 0.01 M aqueous calcium chloride solution at 25 °C, by natural, acid-treated bentonite samples, and humic acid, have been studied by using batch experiments in order to evaluate the potential of these materials for their application in controlled-release formulations of pesticides. The experimental data have been fitted to the Freundlich equation in order to calculate the adsorption capacities (Kf). Kf values ranged from 1.76 mg kg−1 for the untreated bentonite up to 126.9 mg kg−1 for the humic acid. A correlation study was performed with T50, the surface area (S) and the Freundlich parameter (Kf) of the bentonite samples in order to know the factors that affect release rate of imidacloprid from bentonite granules. A linear correlation of the T50 values and both S and Kf parameters was observed. © 1999 Society of Chemical Industry

Use of bentonite and humic acid as modifying agents in alginate‐based controlled‐release formulations of imidacloprid

In order to prepare a formulation to be used for controlled release, imidacloprid was incorporated into alginate granules by using calcium chloride as gellant. The formulation prepared (alginate–imidacloprid–water) was modified by the addition of different sorbents. The effects on release rate of the addition of natural bentonite desiccated at 105 °C, untreated, acid-treated with sulfuric acid solutions over a concentration range between 0.5 mol dm−3 and 2.5 mol dm−3, and a commercial humic acid, were studied by immersion of the granules in water under static conditions. The time taken for 50% of the active ingredient to be released into water, (T50), was calculated from the data obtained. On the other hand, the sorption–desorption processes of imidacloprid from a 0.01 M aqueous calcium chloride solution at 25 °C, by natural, acid-treated bentonite samples, and humic acid, have been studied by using batch experiments in order to evaluate the potential of these materials for their application in controlled-release formulations of pesticides. The experimental data have been fitted to the Freundlich equation in order to calculate the adsorption capacities (Kf). Kf values ranged from 1.76 mg kg−1 for the untreated bentonite up to 126.9 mg kg−1 for the humic acid. A correlation study was performed with T50, the surface area (S) and the Freundlich parameter (Kf) of the bentonite samples in order to know the factors that affect release rate of imidacloprid from bentonite granules. A linear correlation of the T50 values and both S and Kf parameters was observed. © 1999 Society of Chemical Industry

Lignins as formulating agents for controlled release in agriculture

AbstractThe use of naturally‐occurring polymers, and in particular, kraft lignin, for controlled release pesticide formulations is reviewed. A matrix of kraft lignin containing polar pesticides can be prepared in granular form and the release rates of the active ingredient from this formulation are described. Successful applications of this type of formulation include herbicides for weed control in conifer plantation and insecticides in tropical flooded rice.

Pestizide polymere IV Untersuchung pestizider controlled release formulierungen mit LDPE und EVA

Polymeric controlled release pesticide formulations of some selected pesticides in LDPE und EVA were drawn in cable. The migration of the active agents from the polymer matrix into the water were detected and the diffusion coefficients D O were calculated. The values of D o = 10 −8 − 10 −12 [cm 2 · s −1] were in the same order of magnitude as other common polymer additives. The duration of the migrations were extrapolated to two months up to several years and it depended on the chemical structure of the active agents, the polymer matrix and the surface area of the formulations. By changing one or all the mentioned parameters the migration rate can be accordingly increased or decreased. To avoid the increase of stable polymers in ecosystem a removable application technique should be developed.