Ultrafine Oil Research Articles

Destructing surfactant network in nanoemulsions by positively charged magnetic nanorods to enhance oil-water separation

The separation of ultrafine oil droplets from wasted nanoemulsions stabilized with high concentration of surfactants is precondition for oil reuse and the safe discharge of effluent. However, the double barriers of the interfacial film and network structures formed by surfactants in nanoemulsions significantly impede the oil-water separation. To destroy these surfactant protective layers, we proposed a newly-developed polyethyleneimine micelle template approach to achieve simultaneous surface charge manipulation and morphology transformation of magnetic nanospheres to magnetic nanorods. The results revealed that positively charged magnetic nanospheres exhibited limited separation performance of nanoemulsions, with a maximum chemical oxygen demand (COD) removal of 50%, whereas magnetic nanorods achieved more than 95% COD removal in less than 30 s. The magnetic nanorods were also applicable to wasted nanoemulsions from different sources and exhibited excellent resistance to wide pH changes. Owing to their unique one-dimensional structure, the interfacial dispersion of magnetic nanorods was significantly promoted, leading to the efficient capture of surfactants and widespread destruction of both the interfacial film and network structure, which facilitated droplet merging into the oil phase. The easy-to-prepare and easy-to-tune strategy in this study paves a feasible avenue to simultaneously tailor surface charge and morphology of magnetic nanoparticles, and reveals the huge potential of morphology manipulation for producing high-performance nanomaterials to be applied in complex interfacial interaction process. We believe that the newly-developed magnetic-nanorods significantly contribute to hazardous oily waste remediation and advances technology evolution toward problematic oil-pollution control.

Preparation and Characterization of Ultra-Fine Oil Palm Ash Powder by Ultrasonication and Alkaline Treatment for Its Evaluation as Reinforcing Filler in Natural Rubber.

Ultra-fine oil palm ash (OPA) particles were successfully prepared using ultrasonication along with optimal chemical deagglomeration. The influence of chemical treatment by sodium hydroxide (NaOH) solution on the OPA particles was found to be an important factor in enhancing deagglomeration efficiency. The average particle size of the original OPA (41.651 μm) decreased remarkably more than 130 times (0.318 μm) with an obvious increase of Brunauer–Emmet–Teller (BET) surface area after treating the OPA with 3M NaOH, followed by ultrasonication for 30 min. The changes in particle size and surface morphology were investigated using transmission electron microscopy and scanning electron microscopy. Moreover, the chemical functional groups of the untreated and treated OPA showed different patterns of infrared spectra by the presence of sodium carbonate species owing to the effect of NaOH treatment. The incorporation of both untreated and treated OPA in natural rubber by increasing their loading can improve cure characteristics (i.e., reducing optimum cure time and increasing torques) and cure kinetic parameters (i.e., increasing the rate of cure and reducing activation energy). Nevertheless, the strength, degree of reinforcement, and thermal stability of treated OPA as well as wettability between treated OPA particles and NR were greater than that resulting from the untreated OPA.

Development of antimicrobial medical cotton fabrics using synthesized nanoemulsion of reactive cyclodextrin hosted coconut oil inclusion complex

Reactive cyclodextrin (RCD) based nanoemulsion and loaded with coconut oil in presence of Tween 80 emulsifying agent for development of antimicrobial medical cotton fabrics is the subject of current research. RCD based nanoemulsion was prepared at different stirring duration, viz, 2, 4, 6 and 24 h in presence of Tween 80. This was done in order to induce varieties in size and morphology of the nanoemulsion. The coconut oil encapsulated RCD based nanocomposite was precipitated as powder using centrifugation technique for 60 min at 4500 rpm and the resulted powder was investigated using TEM and SEM techniques. The images that provided by these techniques confirmed the nano-sized scale of the coconut oil loaded RCD nanocomposite. In addition, the entrapment efficiency of coconut oil loaded RCD based nanoemulsion after centrifugation was calculated and was found to more than 93 %; this is a proof for the successful inclusion of the coconut oil inside the cavity of RCD molecules. Moreover, the obtained RCD based nanoemulsions were applied to bleached cotton fabrics as per the pad-dry-cure method. The as treated cotton fabrics were monitored for nitrogen content, add-on, mechanical properties and morphology vis-a-vis those similarly treated fabrics but using the as prepared microemulsion of RCD loaded with coconut oil in absence of Tween 80. The morphological structure of cotton fabrics treated with the nanoemulsion in question was also examined using SEM technique. Moreover, the biological activity of the nanoemulsion finished fabrics before and after being submitted to 20 washing cycles was investigated against different types of bacteria and fungi as per the inhibition zone method. Results obtained signify: (i) deposition on the fabric of coconut oil loaded RCD nanoemulsion; (ii) the add-on of the nanoemulsion on the surface of cotton fabric is a manifestation of the stirring duration, proofing the formation of ultrafine oil nanoemulsion which penetrates the fabric surface; (iii) the finished fabrics display antimicrobial activity with clear excellent inhibition zone even after 20 washing cycles, indicating the protection of these fabrics for human beings from harmful microbes. In conclusion, the cotton fabrics treated with nanoemulsion of RCD loaded coconut oil is considered as an effective super antimicrobial medical textile against pathogenic microorganisms of both bacteria and fungus species.

Influence of the ultrafine oil additives on friction and vibration in journal bearings

In order to study the influence of ultrafine additives on hydrodynamic lubrication in journal bearings, this paper combines experimental and simulative approaches. The lubricants׳ samples were obtained by means of adding the fullerene black, fullerenes, molybdenum disulfide and fluoropolymer in quantity no higher than 0.05% of the mass in base low-viscosity mineral oil. The experiment was made during the run-down of the rotor, and we measured the friction coefficient in the journal bearing and the vibrations of its housing. The simulation model based on the developed methodology of setting and solving of the variational problem, allowed to explain and reproduce the results of the experiment. Ultrafine additives significantly decreased the load-carrying capacity and the friction coefficient in the journal bearing, as well as the vibration level in the bearing. The rate of lowering of friction and vibration directly depended on the level of pseudoplastic properties of the sample. The best results were shown by samples with fullerene black and fluoropolymer.

Synthesis of a Novel Dendrimer-Based Demulsifier and Its Application in the Treatment of Typical Diesel-in-Water Emulsions with Ultrafine Oil Droplets

Waste water resulted from polymer flooding oil recovery generally has a bad impact on the subsequent process of enhanced oil recovery. Separating residual oil from oil/water (O/W) emulsion with suitable kinds of demulsifier is one strategy generally adopted by oil companies. Because of the existence of large amounts of ultrafine oil droplets with the average diameter less than 2 μm, the emulsions can be extremely difficult to break up. To solve this problem, an amine-based dendrimer demulsifier PAMAM (polyamidoamine) was synthesized in this study, and the efficiency of the demulsifier in dealing with O/W emulsions with ultrafine oil droplets was investigated. Because of its strong interfacial activity and relatively good solubility in water, the dendrimer-based demulsifier can easily attach to emulsified oil droplets in a stable diesel-in-water emulsion. The influences of temperature, settling time, and concentration of the demulsifier used on the efficiency of the demulsifier were investigated in detail. The optimal operating condition under which more than 90% oil was removed from the original emulsion by the demulsifier was found. In contrast, less than 2% oil was removed from the emulsion without applying the demulsifier under the same conditions. Micrographs showed that the PAMAM demulsifier could lead to the breakup of diesel-in-water emulsions with ultrafine oil droplets by flocculation and coalescence. The surface tension and interfacial tension at the diesel–water interface were also measured to give a basic understanding of the demulsification mechanism. Though not perfect in dealing with emulsions with the average oil droplets less than 2 μm due to the relatively high demulsifier dosage, its relatively simple synthetic procedure and mild operating conditions showed a great promise in industrial applications with unique advantages over traditional physical methods.

Management of Powdery Mildew on Flowering Dogwood with Soybean Oil

Abstract Soybean oil formulations developed in our laboratory were evaluated for control of powdery mildew on flowering dogwood Cornus florida. In a preliminary trial in a field nursery, two formulations, TNsoy1 and TNsoy2 [0, 1 or 2% (v/v)], were applied to field-grown flowering dogwood at 2 wk intervals from June 10 until August 19. Soy oil-treated trees had less powdery mildew, higher net photosynthetic rate and growth rate than unsprayed trees, without apparent phytotoxicity. Leaves sprayed with Banner MAXX had less powdery mildew and higher photosynthetic rates than oil treated leaves. These same treatments applied the next year under more frequent rain showers did not provide satisfactory control. Newer soybean oil formulations using natural or food grade emulsifiers, were compared to three commercial botanical oil formulations and to SunSpray Ultra Fine Oil in greenhouse trials. All oil formulations provided some protective and eradicative control of powdery mildew. Photosynthesis of oil treated leaves was usually depressed, compared to controls, for several days but recovered. In greenhouse trials where the oil was not washed off by rain or irrigation, the oil residue was visible on leaves, reduced powdery mildew severity, and depressed photosynthesis for several weeks. In a second greenhouse trial, soybean oil formulations provided greater control if applied after rather than before initial inoculation.

Effect of Concentration on Electrospinning Oil Sorptive Fiber

Electrospinning is a convenient method used in the preparation of ultrafine oil sorptive fibers based on Ethylene-propylene-diene (EPDM), Electrospun fiber diameter, varying in large from micrometer to nanometer, mainly depends upon the solution concentration, which has great influence on this function fiber’s sorption ability. The non-linear relation between mean fiber diameter (d) and solution concentration (C) was investigated and it follows a simple scaling law in the form . This relationship can be used to predict the target fiber diameter and guide the processing technique. The effects of various C on oil sorption ability were investigated in a batch-sorption technique. A comparison of the kinetic models, showed that the removal rate fit the first order kinetic model well, which suggested the sorption process is rapid, can reach equilibrium within a short time.

Laboratory Evaluation of Products to Reduce Settling of Sweetpotato Whitefly Adults

The impact of trademarked and commercial products on settling of adults of the sweetpotato whitefly, Bemisia tabaci (Gennadius), was studied in the laboratory. A no-choice bioassay using leaf disks of tomato, Solanum esculentum L., was developed to evaluate the impact of concentration series of products on settling of B. tabaci adults. The concentration of each product that would reduce settling by 50% (SC50) was estimated for each product using standard probit analyses, and the values were compared with that of Ultra-Fine Oil, a paraffinic oil product that is known to reduce settling of whitefly adults. Twenty-two trademarked products and 42 other products were evaluated in the laboratory bioassay. Based upon comparisons of fiducial limits of the respective SC50 values, Dawn detergent and E-RASE jojoba oil were the only trademarked products that were as effective as Ultra-Fine Oil in reducing settling of B. tabaci adults. Of the nontrademarked products, 25 were similar to Ultra-Fine Oil, although cedar, geranium, ginger, Hamlin (citrus), patchouli, olive and wintergreen oils, as well as citronellal and limonene, had ratios of respective SC50 values with that of Ultra-Fine Oil of approximately 1.5 or less. Combinations of limonene and citronellal with either olive oil or Ultra-Fine Oil were 15 and 30 times, respectively, more effective than Ultra-Fine Oil alone. Candidate products and combinations of products were further evaluated on tomato seedlings in no-choice screenhouse trials for effects on oviposition and on transmission of Tomato yellow leaf curl virus (family Geminiviridae, genus Begomovirus, TYLCV) by B. tabaci. Ultra-Fine Oil and olive oil reduced oviposition and transmission of TYLCV in the screenhouse trials. Ginger oil and limonene reduced oviposition in at least one screenhouse trial but did reduce transmission of TYLCV. The laboratory bioassay provided a rapid and relatively easy method to compare products for reducing settling of B. tabaci adults. Even though the reduced settling indicated in the laboratory bioassays was not always reflected in reduced oviposition or TYLCV transmission in the screenhouse trials, the bioassay was useful in rapidly identifying products that reduce settling and that could be investigated further.

Synthetic and Biorational Fungicides Compared for the Control of Three Foliar Diseases of Flowering Dogwood

Abstract The biorational fungicides Neem Concentrate, SunSpray Ultra Fine Oil®, Rhapsody® were compared with the synthetic fungicides Eagle® 40W, Immunox®, Liquid Systemic Fungicide®, and 3336™ 50W for the control of spot anthracnose, Cercospora leaf spot, and powdery mildew on ‘Rubra’ flowering dogwood. In 2003, 2004, and 2005, fungicide treatments were applied at label rates at 1- and/or 2-week intervals over a period that coincided with the onset spot anthracnose and powdery mildew but before the appearance of Cercospora leaf spot. With few exceptions, the synthetic fungicides gave better control of the above diseases than biorational fungicides. Eagle 40W, Immunox, Liquid Systemic Fungicide, and 3336 50W gave equal control of the bract and leaf spot phases of spot anthracnose. Most notable was the carryover of control of the bract spot phase of spot anthracnose into the spring of the following year with the synthetic fungicides. While some control of spot anthracnose was seen in at least one year with the biorational fungicides, none was as effective as the synthetic fungicides. In 2003 and 2004, Neem Concentrate, SunSpray Ultra Fine Oil, and Rhapsody, when applied weekly controlled powdery mildew as effectively as the synthetic fungicides. Efficacy of the biorational fungicides declined under severe powdery mildew pressure in 2005. While Cercospora leaf spot development was slowed by the Eagle 40W, Liquid Systemic Fungicide, and 3336 50W, the biorational fungicides as well as the retail product Immunox also gave some control. An objectionable mottling of the leaves was noted on the flowering dogwood treated with SunSpray Ultra Fine Oil. Control of these diseases with the synthetic or biorational fungicides did not result in an increase in tree height or trunk diameter. While the biorational fungicides demonstrated sufficient efficacy for controlling powdery mildew on flowering dogwood in the landscape, they often failed to provide the level of control of this disease as well as spot anthracnose and Cercospora leaf spot needed to produce quality container- and field-grown nursery stock.

Comparison of Fungicides for the Control of Powdery Mildew on Dogwood

Abstract Efficacy of selected registered fungicides and trifloxystrobin, was evaluated for the control of powdery mildew (Erysiphe pulchra) on container-grown flowering dogwood (Cornus florida). Bare-root trees were transplanted into a pine bark/peat moss substrate and maintained under a 47% shade cloth. All fungicide treatments significantly reduced the incidence of powdery mildew compared with the untreated control. During the trial period, the most consistent control of powdery mildew was given by azoxystrobin [Heritage® 50W] at 0.16 g ai/liter or propiconazole [Banner MAXX®] at 0.07 g ai/liter, respectively. In two of three years, myclobutanil [Eagle® 40W] at 0.24 g ai/liter was equally effective in controlling this disease as the above fungicides. Copper sulfate pentahydrate [Phyton 27®] at 0.74 g ai/liter gave similar control of powdery mildew in three of four years as propiconazole but was not quite as effective in controlling this disease as azoxystrobin. Paraffinic oil at 1% v/v [Sunspray Ultrafine Oil®] was slightly less effective in controlling powdery mildew than azoxystrobin or myclobutanil. However, no more than 6% leaves on the paraffinic oil-treated dogwood were colonized in any year by E. pulchra, compared with 75% colonization for the untreated controls. Although thiophanate methyl [3336™ 4.5F] at 0.84 g ai/liter and triadimefon [Bayleton® WSP] at 0.16 g ai/liter reduced powdery mildew incidence compared with the untreated control, the level of leaf colonization in three of four years was significantly higher than other fungicides. Trifloxystrobin [Compass™ 50W] at the 0.04 g ai/liter rate gave better control of powdery mildew when applied at 1- and 2-week intervals than on a monthly schedule. In contrast, the 0.08 and 0.16 g ai/liter rate of this fungicide were almost equally effective in controlling this disease at 1-, 2-, and 4-week intervals. When applied on the same schedule, myclobutanil (0.24 g ai/liter) gave the same level of powdery mildew control as all three rates of trifloxystrobin. In 1999, moderate to excellent control of powdery mildew with trifloxystrobin, propiconazole, and azoxystrobin resulted in a significant gains in tree dimensions and trunk caliper over those recorded for the untreated flowering dogwood. No symptoms of phytotoxicity were associated with the use of any of the fungicides screened.

EVALUATION OF THE EFFICACY OF BIOLOGICAL AND SHORT RESIDUAL INSECTICIDES FOR CONTROL OF CITRUS MEALYBUG IN A GREENHOUSE, 2002

Treatments were made on 6 May (first application) and subsequent treatments at 7-day intervals. The BotaniGard + Ultra-Fine Oil received a second treatment three days later on 9 May and a third treatment 7 days later on 16 May. Subsequent treatments to all blocks were applied at 7-day intervals on 14 and 21 May. Plants were grown with substrate of Promix-DX consisting of pine bark, peat moss and perlite with a pH of 6.3. The water used in the trials had a pH of 6.2 and 60 ppm alkalinity. Treatments were made in the afternoon between 1:00 and 3:00 p.m. Sampling was conducted by examining leaves under a dissecting microscope and probing all nymphs and adults. If the CMB moved when probed they were determined to be alive. Prior to analysis data for pre and post-sampling dates were tested for homogeneity. Precount data met the rules of homogeneity and therefore were tested for statistical differences using ANOVA. The post-count data did not meet the rules of homogeneity. To normalized data, data for post counts were log10 transformed, transformed data were analyzed using ANOVA, and a Bonferroni t-test was used to separate treatment means (P ≤ 0.05). Untransformed means are presented in the table.

Soybean Oil as a Summer Spray for Apple: European Red Mite Control, Net CO2 Assimilation, and Phytotoxicity

Soybean [Glycine max (L.) Merrill] oil was applied to apple trees [Malus sylvestris (L.) Mill var. domestica (Borkh.) Mansf.] as a summer spray in six studies to determine if it controls European red mites [Panonychus ulmi (Koch.)], how it affects net CO2 assimilation (A), and if it causes phytotoxicity. Sprays of 0.5%, 1.0%, and 1.5% soybean oil {TNsoy1 formulation [soybean oil premixed with Latron B-1956 (LAT) spreader-sticker at 10 oil: 1 LAT (v/v)]} reduced mite populations by 94%. Sprays of 1% and 2% soybean oil reduced mite populations to three and four mites per leaf, respectively, compared to 25 per leaf on water-sprayed plants. Soybean oil concentrations of 1.0% and 1.5% applied to whole trees reduced A for less than 7 days. Phytotoxicity did not occur when soybean oil was applied with an airblast sprayer at concentrations of 1.0% and 1.5% or with a mist bottle at 2%. Phytotoxicity occurred when soybean oil was applied with a mist bottle at 4% and 6%, which left soybean oil leaf residues of 0.22 to 0.50 mg·cm-2. No phytotoxicity occurred with 4% SunSpray, which resulted in a mean leaf residue of only 0.13 mg·cm-2. Spraying 1% soybean oil tended to give better mite control than 1% SunSpray Ultra-Fine oil, but caused greater oil residues and a greater reduction in A.

Effects of biorational pesticides on four coccinellid species (Coleoptera: Coccinellidae) having potential as biological control agents in interiorscapes.

The direct toxicity of insecticidal soap, horticultural oil, Azatin, an extract from the Neem tree containing azadiractin, and BotainiGard, a commercial formulation of the entomopathogenic fungus Beauveria bassiana, was assessed on adults of four species of coccinellids--Hippodamia convergens (Guérin-Ménéville), Coleomegilla maculata (DeGeer), Harmonia axyridis Pallas, and Cryptolaemus montrouzieri Mulsant. All biorationals caused less mortality than a conventional pesticide, carbaryl (Sevin). Horticultural oil (Sunspray ultrafine oil) consistently had no effect on beetle survivorship. Insecticidal soap (M-Pede) significantly reduced survival in all replicates for C. maculata and in at least one of the three replicates for the other three coccinellid species. Beauveria bassiana (BotaniGard) significantly reduced survival of C. montrouzieri at 72 h after spray in all three replicates. Azatin reduced survivorship in only one species, C. maculata, in only one of the three replicates.

252 Oil Emulsions Enhance Transcuticular Movement of Captan into Apple Leaves

Oil sprays increase the phytotoxicity of captan to apple foliage. The purpose of this study was to determine if oils increase the penetration of captan through leaf cuticles. Enzymatically isolated apple leaf cuticles were used as a model system to study captan penetration. A bioassay was developed using the inhibition of growth of Penicillium cyclopium on potato-dextrose agar as a measure of captan penetration through the cuticle. Captan penetrated through both surfaces, but significantly more penetrated through the abaxial cuticles than the adaxial cuticles. Increasing the captan concentration increased the captan penetration through the abaxial cuticle in a linear relationship. Captan penetration through the cuticle was increased by 63% when cuticles were treated with captan plus 1% emulsified soybean oil. Abaxial cuticles treated with captan plus emulsified soybean oil or with captan plus SunSpray Ultra-Fine oil had >125% greater captan penetration than cuticles treated with only captan. Cuticles treated with captan plus dormant oil (petroleum oil) had 220% more captan penetration than the captan only treatment.

Soybean Oil Used as an Alternative Pesticide on Nursery Stock

Research was conducted to determine if soybean oil sprays may substitute for petroleum oil for control of insects on nursery crops. Dormant field-grown `Globe' arborvitae shrubs infested with Fletcher scale were sprayed on 9 Mar. 1997 with 0%, 2%, 3%, or 4% soybean oil. One hundred scales per plant were evaluated on 4 Apr. 1997. Spraying 2% to 4% soybean oil on dormant arborvitae caused ≥97% mortality of Fletcher scale compared to only 7% mortality on untreated plants. of white pine, viburnum, `Anthony Waterer' spirea, `Green Beauty' boxwood, western red cedar, `Blue Star' juniper, `Blue Pacific' juniper, `Japanese Garden' juniper, and arborvitae plants in trade gallon pots and `Densiformus' yew and dwarf `Alberta' spruce in trade quart pots were sprayed with 0% (water control), 1%, or 2% soybean oil (emulsified with Latron B-1956) or 2% SunSpray Ultra-Fine Spray oil on 26 Aug. 1997 for phytotoxicity evaluation. No phytotoxicity occurred on western cedar, spirea, boxwood, yew, arborvitae, or viburnum. Spraying Sunspray or soybean oil caused initial loss of blue color on blue junipers and white pine. Spraying 1 or 2% soybean oil or 2% SunSpray caused phytotoxicity to `Blue Star' juniper. The `Blue Pacific' juniper, `Japanese Garden' juniper, and Alberta spruce were slightly damaged by 2% but not by 1% soybean oil.

An Evaluation of Repetitive Summer Horticultural Oil Sprays on Selected Woody Landscape Plants

Abstract In order to evaluate the effect of repetitive verdant horticultural oil sprays on plant growth and appearance, 32 different species/cultivars of shade trees, evergreens, and woody shrubs were sprayed three times during the 1994 growing season with 2% SunSpray Ultra-Fine spray oil. Visual phytotoxicity ratings were assigned to treated plants and growth affects were measured by measuring leaf area and incremental twig growth following the last spray application. No phytotoxicity was observed on any of the 32 species/cultivars of woody plants using three repetitive verdant horticultural oil sprays. Collectively, repetitive oil sprays did not significantly affect incremental twig growth or leaf area of treated plants. Results from this study show that repetitive sprays of 2% SunSpray Ultra-Fine spray oil can be used safely on shade trees, evergreens, and deciduous landscape shrubs commonly grown in the upper mid-west.

Insecticidal Effects of Vegetable Oil on Silverleaf Whitefly, 1996

Abstract All but the top 3-4 fully expanded leaves were removed from 45-50 cm tomato plant with 7-9 leaves and 35 to 40 cm collard with 6-7 leaves. Plants were exposed for 72 h (Test 1) or 24 h (Test 2) to a greenhouse colony of silverleaf whitefly for oviposition. The plants were then incubated 10 d. Second instars predominated in both tests. The 3 vegetable oils labeled “A”, “B”, and “C” (Integrated Biocentrol Systems, Inc., Lawrenceburg, IN), 20 ml each, were measured into plastic vials with 5 ml of the non-ionic surfactant APSA 80 and mixed using a Vortex mixer for about 1 min. Dilutions of 0.5 and 1.0% were made by adding the correct amount of each mixture drop by drop to a 500 ml beaker filled with R.O. purified water while stirring on a magnetic stirring plate. The dilutions were stirred for an additional 2-3 min for a total stirring time of 5-10 minutes. All mixtures emulsified well. APSA 80 [0.04%(AI)] and Sunspray Ultra Fine Oil (Sun Refining & Marketing Co., Philadelphia, PA), were also tested and water was used the check. Leaves bearing an average of 120 whitefly nymphs (range: 70-179) were removed from the plant and placed abaxial side up at the bottom of a Potter Spray Tower. The tower was operated at 10 psi to deliver a volume of 3 ml. Treated leaves were placed, petiole down, in water-filled 20ml vials and incubated in an insectary 25 ± 2°C, 55-60%RH and a photoperiod of 14:10 (L:D) h for 5-7 days. Because of non-uniform age distribution in the first test, only dead 2nd instars and live 3rd and 4th instars were recorded. Pupae (dead or alive) were not recorded because they would have been 3rd or 4th instars when treated. For the second test, all dead and live whitefly nymphs were counted under a stereoscopic microscope.

Leaf-Dip Contact Toxicity Bioassays of Biorational Insecticides to Sweetpotato Whitefly Immature Stages, 1993

Abstract Three biorationals used were: M-Pede, an insecticidal soap (Mycogen Corp., San Diego, CA); Sunspray® Ultra-fine Spray Oil (Safer Incorporated, Newton, MA) and Nicotiana gossei extract (Phytochemistry Res. Lab., USDA-ARS). Acetone was used to dissolve the extract. Bifenthrin 10 WP (Brigade*) (FMC Corp., Middleport, NY) and water were used as controls. A colony of Bemisia tabaci was maintained in greenhouse cultures on tomato plants. Test plants were placed in the whitefly infested greenhouse for 24 h, after which adults were removed and excluded. Plants were caged for 7 d or 14 d until the appropriate stages were ready for bioassay. For bioassays of eggs, egg-bearing leaves were dipped in insecticide solution and at 7 d, numbers of hatched and unhatched eggs was recorded. Leaves infested with 7-day old nymphs were dipped in dilutions of insecticides, placed individually in 20 ml glass vials filled with water and kept inside clear plastic cages for 4 d, when dead and live nymphs were examined. Plants infested with 14-day old nymphs were sprayed to runoff and caged for 10 d, when dead nymphs were recorded. Experiments were conducted at 25 ± 2°C, RH 70% ± 5%, and L:D 14:10.

Controlling Powdery Mildew in Euonymus with Polymer Coatings and Bicarbonate Solutions

Powdery mildew in euonymus (Euonymus japonica Thunh.) plants, caused by Oidium euonymi-japonica (Arcang.) Sacc., was controlled by applying various polymer coatings or an aqueous solution of sodium or potassium bicarbonate plus horticultural Sun Spray (SS) Ultra Fine Oil 1% (v/v) to plant foliage. The combined treatment (bicarbonate + oil) was more effective than either of the two materials alone. The results indicate that sodium or potassium (but not ammonium) bicarbonate solutions mixed with SS seems to be a useful biocompatible fungicide for controlling powdery mildew in euonymus plants. Some of the polymer coatings effectively reduced disease levels when applied immediately after the symptoms first appeared.

Phytotoxicity of Sunspray Ultra-Fine Spray Oil and Safer Insecticidal Concentrate Soap on Selected Ornamental Plants in Summer in North Florida and South Georgia

Two percent Sunspray Ultra-fine SprayR oil and Safer Insecticidal ConcentrateR soap were applied 5 times in separate treatments to 30 species of trees and shrubs growing in containers under commercial nursery conditions in north Florida. A similar test was conducted on 17 species of container-grown ornamentals in south Georgia. Horticultural oil and soap were applied at 10 day intervals beginning July 16, 1990. Plants were visually rated for phytotoxicity prior to the second through fifth application and 10 days after the fifth application. A third test of only thre* applications of horticultural oil or soap on 9 species of plants was conducted at Monticello, Florida beginning August 28, 1990. All the treatments were applied from 9:30 - 11:00 A.M. and daily temperatures were above 35° each day. No phytotoxicity was observed on any of the plants tested.