Water-dispersible Granule Formulation Research Articles

Working conditions and health risks of operators in the application of pesticides based on mancozeb on high horticultural crops

Introduction. The increased interest in viticulture in Russia makes mancozeb-based fungicides in demand. Safety and health of operators during application pesticides is a major concern in agricultural activities. Materials and methods. Field studies to determine the exposure of various formulations of mancozeb in the air of the working area and on the skin of the operators during airblast spraying of orchards were carried out. Margin of safety by exposure (KBtotal) and by absorbed dose (KBabs) were conducted. Exposure assessment included the determination of its probability. Results. Wettable powders compared with water-dispersible granules show a fivefold increase in the average concentrations of mancozeb found in the air of the work area and almost a threefold increase in the skin. Exposure and absorbed dose risk rates for wettable powders are three times higher than for water-dispersible granules. For one of the drugs, the total risk was higher than the tolerable risk. The probability distribution vector of possible danger states for the operator after the sixth hour of work shows the probability of an unacceptable state as the highest. Limitations. The scopes of the study were determined by studying the behaviour of mancozeb in the formulations of the wettable powder and water-dispersible granules during airblast spraying of orchards. Conclusion. For health safety purposes, mancozeb-based preparations should be used in compliance with the regulations and safety measures. Operators, who handle and apply pesticides in orchards, should be forcing to wear protective garments and personal protective equipment. The choice of water-dispersible granules formulation is preferable. Don’t exceed the application rate and spraying time.

The Effects of Formulation on Imidacloprid Dissipation in Grapes and Vine Leaves and on Required Pre-Harvest Intervals under Lebanese Climatic Conditions.

In this study, imidacloprid, a systemic insecticide, currently having a specified European Commission MRL value for vine leaves (2 mg kg−1), was applied on a Lebanese vineyard under different commercial formulations: as a soluble liquid (SL) and water dispersible granules (WDG). In Lebanon, many commercial formulations of imidacloprid are subject to the same critical good agricultural practice (cGAP). It was, therefore, important to verify the variability in dissipation patterns according to matrix nature and formulation type. Random samplings of grapes and vine leaves were performed starting at 2 days until 18 days after treatment. Residue extractions were performed according to the QuEChERS method and the analytical determination using liquid chromatography coupled to tandem mass spectrometry (LC-MS-MS). The SL formulation yielded significantly higher initial deposit than the WDG formulation on grapes and vine leaves. The formulation type did not significantly affect the dissipation rates; the estimated half-lives in grapes and vine leaves were 0.5 days for all imidacloprid formulations. No pre-harvest intervals were necessary on grapes. PHIs of 3.7 days for the SL formulation and 2.8 days for the WDG formulation were estimated on vine leaves. The results showed that the type of formulation and the morphological and physiological characteristics of the matrix had an effect on the initial deposits, and thus residue levels, but not on the dissipation patterns.

Development of a water dispersible granule (WDG) formulation of Bacillus thuringiensis for the management of Spodoptera litura (Fab.)

ABSTRACT The tobacco caterpillar, Spodoptera litura is a key insect pest affecting the crop stand and yield of a wide range of crops, mainly castor. Entomopathogens are known to play a vital role in eco-friendly management of insect pests. The present study was undertaken with the objective of developing a freely flowable WDG formulation of Bacillus thuringiensis (Bt) containing a high percentage of active ingredient coupled with biodegradable adjuvants. Water dispersible granule (WDG) formulation of DOR Bt-127 – a native strain of B. thuringiensis var. kurstaki was prepared by a combination of agglomeration and pan drying method using a binder (guar gum), a wetting agent (Tween-80) and a water-soluble carrier (starch). WDG had good wettability and was effective against S. litura. X-ray diffraction studies revealed semi-crystalline nature of WDG formulation. FTIR spectra of Bt WDG formulation revealed change in transmittance peaks to 1631, 1547 and 1147 cm−1 from 1636, 1534 and 1075 cm−1 of Bt (technical) indicating binding of Bt with starch and guar gum. The formulation has a high protein content of 134.7 mg/g and potency of 74,200 SU/mg against 9 days old S. litura larvae. Pot culture studies and field trials revealed that efficacy of Bt-127 WDG formulation was on par with the commercial Btk formulation against 7 and 9 days old larvae. Bt-127 WDG formulation was promising against early as well as older instar larvae and therefore has a prospective to be used in Bio-intensive Integrated Pest Management programmes to reduce the usage of synthetic chemical insecticides.

Determination of thiamethoxam and its metabolite clothianidin residue and dissipation in cowpea by QuEChERS combining with ultrahigh-performance liquid chromatography-tandem mass spectrometry.

The dissipation and residue levels of thiamethoxam and its metabolite clothianidin in cowpea were investigated under field conditions. Samples of cowpea were analyzed using a QuEChERS technique with ultra-performance liquid chromatography tandem mass spectrometry. The recoveries were 86.5-118.9% for thiamethoxam and 75.6-104.1% for clothianidin, with the coefficient of variation of < 13%. The water dispersible granule formulation of thiamethoxam was applied on cowpea at 30 and 45 g active ingredient ha-1 in accordance with good agricultural practice. The half-life of thiamethoxam in cowpea was 0.8-1.6 days. The cowpea samples were gathered at 3, 7, and 10 days after the last application, and the residues of thiamethoxam in cowpea were < 0.005-0.054 mg kg-1, while those of clothianidin were < 0.005-0.008 mg kg-1. The final residues of thiamethoxam and clothianidin were below the European Union (EU) maximum residue level (0.3 mg kg-1 for thiamethoxam; 0.2 mg kg-1 for clothianidin) in cowpea after a preharvest interval (PHI) of 7 days. This study provided basic data on the use and safety of thiamethoxam and clothianidin in cowpea to help the Chinese government formulate a maximum residue level for thiamethoxam in cowpea.

Performance comparison of dome and basket extrusion granulation

A water dispersible granule (WG) formulation is a dry, solid formulation containing active ingredients intended to be diluted/dispersed in water prior to application. If the co-formulants are properly selected, WGs typically have desirable physical and chemical stability. In addition, storage and transport of dry formulations are inherently easier than liquid formulation types. WG formulations of agricultural products offer the added advantage of low dust and safer handling compared to wettable powders (WP).WG formulations can be prepared via several types of granulation processes, with paste extrusion being the most common in crop protection products. Granules created by paste extrusion generally offer improved resistance to attrition, and higher and more consistent bulk density compared to WP formulations. Rapid and complete dispersion in a variety of water conditions is a key performance parameters used to evaluate WG formulations.Among common paste extrusion methods, basket and dome extrusion are the two widely used techniques. Basket extrusion is thought to be less process sensitive. Historically, products originally designed to be dome extruded can often be basket extruded, but not vice versa. In this work, milled powder premixes of varying water solubility are paste extruded using these two technologies. The paste extrudates are dried using a lab scale vibratory fluidized bed. The products are compared based on measured performance quality criteria including dispersion, bulk density, suspensibility, wet sieve, and moisture sorption. Additionally, microscopic characterizations proved valuable in elucidating certain performance differences.

Augmentation of stimulated Pelomonas aquatica dispersible granules enhances remediation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) contaminated soil

Abstract In this study, we explored the hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) degradation potential of a gram-negative bacterium Pelomonas aquatica strain 12868. The microbe eliminated 80.68% of RDX by utilizing the explosive as a nitrogen source. FTIR study and nitrite assay confirmed the degradation of RDX into non-toxic metabolites in an RDX-succinate aqueous medium. The isolate showed an improved RDX degradation when formulated into water dispersible granules (WDG) using soy flour as a nutrient source. The WDG formulation not only achieved 6.53% enhanced RDX degradation but also stabilized the microbe as only a 24.37% decrease in cfu count was observed after a storage period of six months at 30 oC. During the microcosm experiments, RDX degradation followed first-order kinetics with a half-life of 13.9 and 19.04 days in a soil biostimulated by sucrose and wheat straw, respectively. P. aquatica with sucrose as added carbon source effectively degraded 50.91% more RDX compared to unstimulated control after 30 days of treatment. These data imply that microbial formulation mediated RDX reduction coupled with biostimulation has the potential to become a swift and sustainable clean-up approach for RDX contaminated environments.

Disease Control Attributes of Oxathiapiprolin Fungicides for Management of Cucurbit Downy Mildew.

Oxathiapiprolin, a novel oomycete fungicide recently registered by DuPont, was reported to have high intrinsic activity against cucurbit downy mildew (Pseudoperonospora cubensis). The goal of this study was to characterize disease control attributes of oxathiapiprolin-based fungicides critical to effective management of cucurbit downy mildew. In growth chamber and greenhouse studies, oxathiapiprolin-based fungicides were compared with mandipropamid, mefenoxam + mancozeb, fluopicolide + propamocarb, cymoxanil + mancozeb, and ametoctradin + dimethomorph products for pre- and postinfection activity, local systemic movement, and protection of new growth produced after fungicide application. In preventive application, oxathiapiprolin-based fungicides significantly (P < 0.0001) inhibited downy mildew development, with the highest level of disease observed being 0.4% compared with 86.7% observed for mandipropamid. When applied postinfection, oxathiapiprolin-based fungicides significantly (P < 0.0001) suppressed disease development, but disease control was reduced relative to that observed for preventive application. There was a significant effect of formulation on the postinfection activity of oxathiapiprolin, whereby the oil dispersion (OD) formulation was more inhibitory than the water-dispersible granule formulation (0.001 ≤ P ≤ 0.049). Disease severity on the outer half leaf portion protected from spray deposition during fungicide application was lower for oxathiapiprolin-based fungicides (1.6 to 6.6%) than observed for fluopicolide + propamocarb (10.9 to 23.7%), mefenoxam + mancozeb (40.3 to 51.4%), and the nontreated controls (83.3 to 84.9%), which indicates significant acropetal movement within the leaf. Postinfection applications of oxathiapiprolin-based formulations had the greatest effect on lesion growth and sporangia production compared with the other fungicides in the experiment. When applied preventively to rapidly growing plants in a greenhouse, oxathiapiprolin-based fungicides consistently protected new growth that was not present at the time of application, with the OD formulation reducing disease severity by >75% relative to nontreated plants. The practical implications of these observations are discussed.

Preparation, Pre-clinical and Clinical Evaluation of a Novel Rapidly Absorbed Celecoxib Formulation

Celecoxib (Celebrex®) is the only widely used NSAID that selectively inhibits the COX-2 isoenzyme. Celebrex® is absorbed slowly in the fasted state and food intake further delays absorption. In this work, an amorphous water dispersible granule formulation of celecoxib is described with in vitro characterization, preclinical and clinical data. The formulation exhibited very high passive permeability and apparent solubility, significantly outperforming the micronized celecoxib and the drug product Celebrex®. The granule formulation remained stable for at least 1year in stability tests. In dog studies, tmax was 1h with over 50% of Cmax reached within 15min regardless of food intake. A phase 1 clinical trial was conducted with 12 volunteers at 100- and 200-mg doses. Celecoxib plasma concentrations reached 250ng/ml, the effective therapeutic plasma level, in less than 15min regardless of food or dose. The novel celecoxib formulation is rapidly absorbed, demonstrating the potential utility as an acute treatment offering advantages over the currently marketed product.

Small-scale field testing of alpha-cypermethrin water-dispersible granules in comparison with the recommended wettable powder formulation for indoor residual spraying against malaria vectors in Benin

BackgroundPyrethroids are the most common class of insecticide used worldwide for indoor residual spraying (IRS) against malaria vectors. Water-dispersible granules (WG) are a pyrethroid formulation to be applied after disintegration and dispersion in water with less risks of inhalation than using the usual wettable powder (WP) formulation. The objective of this small-scale field study was to evaluate efficacy and duration of insecticidal action of a new alpha-cypermethrin WG (250 g a.i./kg) against susceptible Anopheles gambiae in comparison with the WHO reference product (alpha-cypermethrin WP, 50 g a.i./kg) on the most common indoor surfaces in Benin.MethodsBoth formulations were applied at two target-dose concentrations in houses made of mud and cement in the Tokoli village in southern Benin. We measured the applied dose of insecticide by chemical analysis of filter paper samples collected from the sprayed inner walls. We recorded An. gambiae mortality and knock-down rates every 15 days during 6 months using standard WHO bioassays.ResultsThe alpha-cypermethrin WG formulation did not last as long as the WP formulation on both surfaces. The difference is higher with the 30 mg/m2 concentration for which the WP formulation reached the 80% mortality threshold during 2 months on the mud-plastered walls (3 months on cement) whereas the WG formulation last only one month (2 months on cement).ConclusionsThe new WG formulation has a shorter efficacy than the WHO recommended WP formulation. In this trial, both the WG and WP formulations had low durations of efficacy that would need at least two rounds of spray to cover the entire transmission season.

Viscosity, surface tension and droplet size of sprays of different formulations of insecticides and fungicides

The influence of three types of commercial formulation of insecticides and fungicides, emulsifiable concentrate (EC) formulation, suspension concentrate (SC) formulation and water dispersible granule (WG) formulation on the surface tension, viscosity and the droplet size spectra of sprays was evaluated using thirty commercial insecticide and fungicide products. The concentration of sprays was based on application water spray volume of 50 L ha−1 using an XR 8003VS flat fan nozzle, operated at 200 kPa pressure. The lowest surface tensions were obtained with EC formulations, while the SCs had the highest viscosities. Emulsions were the most effective at decreasing the percentage of droplets smaller than 100 μm and relative span, while increasing the DV0.1 and DV0.5 values than the dispersion-type formulations, represented by WG and SC formulations. These factors should be considered for planning spray applications and reducing drift.

Simultaneous detection of sulfoxaflor and its metabolites, X11719474 and X11721061, in lettuce using a modified QuEChERS extraction method and liquid chromatography-tandem mass spectrometry.

An analytical method has been developed to quantify the residual levels of sulfoxaflor and its metabolites (X11719474 and X11721061) in/on cultivated lettuce grown under greenhouse conditions. Samples were extracted and purified using a quick, easy, cheap, effective, rugged, and safe 'QuEChERS' method (original version) following systematic method optimization and were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Good linearity with coefficient of determination ≥0.9930 was obtained and the limits of detection (LOD) and quantification (LOQ) were in the ranges of 0.003-0.006 and 0.01-0.02 mg/kg, respectively. The recovery rates of both the parent compound and its metabolites (fortified at 10 and 50× the LOQ) estimated from six replicates ranged between 81.9 and 115.5% with a relative standard deviation <12%. The validated method was applied to field-incurred samples (collected over 7 days) sprayed once or twice with a water-dispersible granule formulation. Notably, a substantial reduction in rate was observed after 3 days and the half-life was short, only 1.5 days. The developed method is simple and versatile and can be used for various leafy vegetables.

Efficacy of water-dispersible formulations of biological control strains of Aspergillus flavus for aflatoxin management in corn

ABSTRACTField experiments were conducted in 2011 and 2012 to evaluate the efficacy of water-dispersible granule (WDG) formulations of biocontrol strains of Aspergillus flavus in controlling aflatoxin contamination of corn. In 2011, when aflatoxin was present at very high levels, there was no WDG treatment that could provide significant protection against aflatoxin contamination. The following year a new WDG formulation was tested that resulted in 100% reduction in aflatoxin in one field experiment and ≥ 49% reduction in all five WDG treatments with biocontrol strain 21882. Large sampling error, however, limited the resolution of various treatment effects. Corn samples were also subjected to microbial analysis to understand better the mechanisms of successful biocontrol. In the samples examined here, the size of the A. flavus population on the grain was associated with the amount of aflatoxin, but the toxigenic status of that population was a poor predictor of aflatoxin concentration.

Determination and analysis of the dissipation and residue of cyprodinil and fludioxonil in grape and soil using a modified QuEChERS method

A simple and accurate method coupled with a gas chromatography-nitrogen phosphorus detector was developed to detect cyprodinil and fludioxonil in grape and soil. The accuracy and precision of the method in detecting the two fungicides were evaluated by conducting intra- and inter-day recovery experiments. The limits of detection were 0.017 mg/kg for cyprodinil and 0.030 mg/kg for fludioxonil. The limits of quantitation were 0.05 mg/kg for cyprodinil and 0.10 mg/kg for fludioxonil in grape and soil. The recoveries of the fungicides in grape and soil were investigated at three spiked levels and were found to range from 85.81 to 102.94% for cyprodinil and from 92.00 to 106.86% for fludioxonil, with relative standard deviations below 7%. Field experiments were conducted in two experimental locations in China. The half-lives of cyprodinil were 9.6-20.8 days in grape and 5.8-15.6 day in soil, and the half-lives of fludioxonil were 6.2-7.2 days in grape and 6.0-12.1 days in soil. When the cyprodinil and fludioxonil 62% water-dispersible granule formulation was sprayed at a low dosage three times, terminal residues of cyprodinil and fludioxonil were below 1.0 mg/kg in grape 14 days after harvest. This work may serve as a reference to establish the maximum residue limits for cyprodinil and fludioxonil in grape and promote the proper and safe use of these two fungicides.

Experimental hut and bioassay evaluation of the residual activity of a polymer-enhanced suspension concentrate (SC-PE) formulation of deltamethrin for IRS use in the control of Anopheles arabiensis.

BackgroundThe Stockholm Convention on Persistent Organic Pollutants (POPs) came into effect in 2004; the use of DDT for malaria control has been allowed to continue under exemption since then due to a perceived absence of equally effective and efficient alternatives. Alternative classes of insecticide for indoor residual spraying (IRS) have a relatively short residual duration of action (2-6 months according to WHO). In areas of year-round transmission multiple spray cycles are required, resulting in significantly higher costs for malaria control programs and user fatigue. This study evaluated performance of a new formulation of deltamethrin (pyrethroid) with polymer (SC-PE) to prolong the effective residual action to >6 months.MethodsDeltamethrin SC-PE was evaluated alongside an existing water dispersible granule (WG) formulation and DDT water dispersible powder (WP) in laboratory and hut bioassays on mud, concrete, palm thatch and plywood substrates. An experimental hut trial was conducted in Lower Moshi Rice Irrigation Zone, Tanzania from 2008-2009 against wild, free-flying, pyrethroid susceptible An. arabiensis. Performance was measured in terms of insecticide-induced mortality, and blood-feeding inhibition. Bioassays were carried out monthly on sprayed substrates to assess residual activity.ResultsBioassays in simple huts (designed for bioassay testing only) and experimental huts (designed for testing free flying mosquitoes) showed evidence that SC-PE improved longevity on mud and concrete over the WG formulation. Both deltamethrin SC-PE and WG outperformed DDT in bioassays on all substrates tested in the laboratory and simple huts. In experimental hut trials SC-PE, WG and DDT produced high levels of An. arabiensis mortality and the treatments were equivalent over nine months’ duration. Marked seasonal changes in mortality were recorded for DDT and deltamethrin treatments, and may have been partly influenced by outdoor temperature affecting indoor resting duration of mosquitoes on sprayed surfaces, although no clear correlation was demonstrated.ConclusionsThere is a limited range of alternative insecticides for IRS, and deltamethrin SC-PE is likely to have an important role as part of a rotation strategy with one or more different insecticide classes rotated annually, particularly in areas that currently have low levels of pyrethroid resistance or low LLIN coverage and year-round malaria transmission.

Effect of two formulations on the decline curves and residue levels of rotenone in cabbage and soil under field conditions

The dissipation and residue levels of rotenone with suspension concentrate (SC) as well as water dispersible granule (WDG) formulations in cabbage and soil were investigated under field conditions. The decline curves of rotenone residues in cabbage and soil corresponded with first-order kinetics. The dissipation rate of rotenone in cabbage was faster than that in soil. The half-lives of the SC formulations in cabbage and soil were 1.14d to 1.85d and 2.26d to 3.98d, respectively. For the WDG formulation, the values were 1.33d to 1.96d and 2.41d to 3.38d. Less spraying, lower dosage, and longer pre-harvest intervals could reduce terminal residue levels. Terminal residues below the MRL (0.5mgkg−1) were achieved after pre-harvest intervals of 3d at either once (45ga.i.ha−1) or twice (90ga.i.ha−1) the recommended dosage. The different dissipation processes of rotenone in cabbage and soil under field conditions could be attributed to the different climate and soil properties, and the types of formulation had no apparent effect on half-life. Formulation type affected the initial concentrations and finally led to different terminal residues. Prolonged pre-harvest intervals are necessary to ensure that the products are sufficiently safe for consumption.

Experimental hut and bioassay evaluation of the residual activity of a polymer-enhanced suspension concentrate (SC-PE) formulation of deltamethrin for IRS use in the control of Anopheles arabiensis

BackgroundThe Stockholm Convention on Persistent Organic Pollutants (POPs) came into effect in 2004; the use of DDT for malaria control has been allowed to continue under exemption since then due to a perceived absence of equally effective and efficient alternatives. Alternative classes of insecticide for indoor residual spraying (IRS) have a relatively short residual duration of action (2-6 months according to WHO). In areas of year-round transmission multiple spray cycles are required, resulting in significantly higher costs for malaria control programs and user fatigue. This study evaluated performance of a new formulation of deltamethrin (pyrethroid) with polymer (SC-PE) to prolong the effective residual action to >6 months.MethodsDeltamethrin SC-PE was evaluated alongside an existing water dispersible granule (WG) formulation and DDT water dispersible powder (WP) in laboratory and hut bioassays on mud, concrete, palm thatch and plywood substrates. An experimental hut trial was conducted in Lower Moshi Rice Irrigation Zone, Tanzania from 2008-2009 against wild, free-flying, pyrethroid susceptible An. arabiensis. Performance was measured in terms of insecticide-induced mortality, and blood-feeding inhibition. Bioassays were carried out monthly on sprayed substrates to assess residual activity.ResultsBioassays in simple huts (designed for bioassay testing only) and experimental huts (designed for testing free flying mosquitoes) showed evidence that SC-PE improved longevity on mud and concrete over the WG formulation. Both deltamethrin SC-PE and WG outperformed DDT in bioassays on all substrates tested in the laboratory and simple huts. In experimental hut trials SC-PE, WG and DDT produced high levels of An. arabiensis mortality and the treatments were equivalent over nine months’ duration. Marked seasonal changes in mortality were recorded for DDT and deltamethrin treatments, and may have been partly influenced by outdoor temperature affecting indoor resting duration of mosquitoes on sprayed surfaces, although no clear correlation was demonstrated.ConclusionsThere is a limited range of alternative insecticides for IRS, and deltamethrin SC-PE is likely to have an important role as part of a rotation strategy with one or more different insecticide classes rotated annually, particularly in areas that currently have low levels of pyrethroid resistance or low LLIN coverage and year-round malaria transmission.

Efficacy of Bacillus thuringiensis var. israelensis against malaria mosquitoes in northwestern Burkina Faso.

BackgroundIn Sub Saharan Africa malaria remains one of the major health problems and its control represents an important public health measure. Integrated malaria control comprises the use of impregnated mosquito nets and indoor residual spraying. The use of drugs to treat patients can create additional pressure on the equation of malaria transmission. Vector control may target the adult mosquitoes or their aquatic larval stages. Biological larvicides such as Bacillus thuringiensis israelensis (Bti) represent a promising approach to support malaria control programs by creating additional pressure on the equation of malaria transmission.MethodsIn this study we examined the efficacy of a water-dispersible granule formulation (WDG) of the biological larvicide Bti (VectoBac®) against wild Anopheles spp. larvae. Different concentrations of the larvicide were tested in standardized plastic tubs in the field against untreated controls. In weekly intervals tubs were treated with fixed concentrations of larvicide and the percentage reduction of larvae and pupae was calculated.ResultsAll used concentrations successfully killed 100 percent of the larvae within 24 hours, while the higher concentrations showed a slightly prolonged residual effect. Natural reconolization of larvae took place after two and three days respectively, late instar larvae were not found before 5 days after treatment. For the higher concentrations, up to three days no new larvae were found, implicating that the residual effect of WDG in tropical conditions is approximately one to two days. The overall pupae reduction in treated tubs was 98.5%.ConclusionsBiological larviciding with Bti can be a promising, additional tool in the fight against malaria in Africa. Environmental particularities in tropical Africa, first and foremost the rapid development of mosquitoes from oviposition to imago have to be taken into account before implementing such counter measures in national or international vector control programs. Nonetheless biological larviciding seems to be an appropriate measure for selected conditions, offering a significant contribution to the future of malaria control.

WG and WP Formulations of Captan with Polymeric Surfactants

Abstract Water-dispersible Granules (WGs) and Wettable Powder (WP) are two important types of agrochemical formulations. The combined shares of WG and WP formulations by volume were 30 % among all the agrochemical formulation types in 2007. WG formulation is continuously increasing in share as a safer and greener formulation type. Both formulation compositions and formulation process affect the performance of WG and WP. This research demonstrated a concise and systematic approach to develop WG via low pressure extrusion process and WP blade-mixer blending process in the laboratory. Specifically, Captan technical as a model active ingredient was formulated together with polymeric dispersants, alkyl sodium sulfosuccinate wetting agents, and Kaolin clay diluents under controlled process conditions. The formulated samples were investigated in suspension stability, disintegration behavior, particle size, and granule morphology, and their composition-structure-performance relationships were discussed.

Winter Annual Broadleaf Weeds and Winter Wheat Response to Postemergence Application of Two Saflufenacil Formulations

Field experiments in winter wheat were initiated at two locations in the fall of 2006 and 2007 to evaluate winter annual broadleaf weeds and winter wheat response to POST applications of two saflufenacil formulations applied alone and in combination with 2,4-D amine. Emulsifiable concentrate (EC) and water-dispersible granule (WG) formulations of saflufenacil at 13, 25, and 50 g ai ha−1were applied with 1.0% (v/v) crop oil concentrate (COC) and mixed with 2,4-D amine at 533 g ae ha−1without adjuvant. Regardless of rate or formulation, saflufenacil plus COC and saflufenacil plus 2,4-D amine controlled blue mustard ≥ 91% at 17 to 20 d after treatment (DAT) compared with ≤ 50% control with 2,4-D amine alone. At least 25 g ha−1of saflufenacil EC was necessary to control flixweed &gt; 90%. Excluding COC from saflufenacil plus 2,4-D amine reduced flixweed control from the saflufenacil WG formulation more than the EC formulation. Most saflufenacil treatments did not control henbit satisfactorily (≤ 80%). Wheat foliar necrosis increased with increasing saflufenacil rate to as high as 30% at 3 to 6 DAT, but declined to &lt; 15% at 10 to 20 DAT and was not evident at 30 DAT. Saflufenacil rate, formulation, and mixing with 2,4-D amine also influenced wheat stunting, but to a lesser extent than foliar necrosis. Saflufenacil EC consistently caused greater foliar necrosis and stunting on wheat than saflufenacil WG. Leaf necrosis and stunting were reduced by tank-mixing saflufenacil formulations with 2,4-D amine without COC. Grain yields of most saflufenacil treatments were similar to 2,4-D amine under weedy conditions and herbicide treatments had no effect on grain yield in weed-free experiments. Saflufenacil formulations at 25 to 50 g ha−1with 2,4-D amine and saflufenacil WG at 25 to 50 g ha−1with COC can control winter annual broadleaf weeds with minimal injury (&lt; 15%) and no grain yield reductions. The addition of saflufenacil as a POST-applied herbicide would give wheat growers another useful tool to control annual broadleaf weeds, including herbicide-resistant weed species.

Application of New Solid Polymeric Dispersant, Easy-Sperse® P-20 (Spray-Dried Polymer Composites) in Suspension Concentrates and Water Dispersible Granule Formulations—Improvement in Suspensibility and Rain-fastnesss

Abstract Easy-Sperse® P-20 [ES P-20] is a synergistic, spray-dried composite of polyvinyl pyrrolidone (PVP) and partially neutralized methyl vinyl ether maleic acid butyl/ethyl half ester polymer. In this work, ES P-20 was used as an additive in water-based suspension concentrate (SC) and water dispersible granule (WDG) for improving the suspensibility and rain-fastness performance of those samples. SC samples with 40 % Diuron, 30 % Isoproturon, and 40 % Imidacloprid were prepared. The suspensibility, rain-fastness, viscosity, pH, heat-aged stability, and particle size distribution were measured and compared. Our data showed that the use of ES P-20 could improve the SC suspensibility. The majority of the samples tested reached&amp;gt;70 % suspensibility at 0.2 %, 0.5 %, and 1 % active ingredients after dilution with water and after 4 h standing at room temperature. For some samples, the suspensibility was found to be&amp;gt;90 %, while the formulations without ES P-20 showed a suspensibility of &amp;lt;50 % in most cases. After adding ES P-20, the SC sample with 40 % Diuron also demonstrated better rain-fastness. This indicates that ES P-20 can enhance water resistance during water rinsing. WDG samples with 90 % Atrazine, 80 % Diuron, and 75 % Nicosulfuron were also made successfully using ES P-20 as one of the polymeric dispersants via a laboratory basket extruder. Performance data including friability/hardness, disintegration, wetting time, and suspensibility were evaluated. The data provided illustrate the advantage of using ES P-20 for improving the suspensibility in water. In conclusion, ES P-20 shows synergy with anionic dispersants in dispersing AIs. It also improves heat-aged stability and reduces settling of the AI with time. The formulations with ES P-20 showed increased resistance to water wash in our laboratory tests. The results demonstrated that ES P-20 can be used effectively in formulating zero volatile organic compound compositions like SC and WDG.