Spray Application Method Research Articles

MODELLING AND TESTING OF SYNCHRONOUS MOTORS WITH PERMANENT MAGNETS

Applying a layer of polymer material to the fabric gives new characteristics to the base fabric. The resulting coated material may have functional properties such as resistance to dirt, liquid penetration, etc., or the finished leather products may have a completely different aesthetic appeal. The choice of the coating method depends on several factors: the type of substrate, the polymer formula and its viscosity for coating, the desired final product and the accuracy of the coating, the economy of the process. In the conditions of modern enterprises, it is advisable to use the spray application method for the application of polymer coatings due to the fact that the roller and brush methods do not provide the opportunity to operate with different forms of parts, and volumetric application is not always economically feasible. Jet application of the material is similar to spraying, but for polymer coatings, the temperature value is important, which in this case is difficult to control. Therefore, it is advisable to use the spraying method for applying polymer coatings The paper presents the results of preliminary research on the breakdown of polymers into droplets. The shape of the flow coming out of the nozzle was determined, and based on this, a model describing this process was developed. It is shown that for a sheet of polymer flow, its thickness is inversely proportional to the distance from the nozzle and K=2sx, calculated knowing the thickness of the sheet at some distance x from the nozzle. For a “hollow cone” spray nozzle with taper angle, θ and orifice diameter, δ and sheet thickness h, at the nozzle exit, an equation for the flow length break was derived. The obtained results of the calculations of the dependence of the droplet diameter on the flow rate. A spray test was carried out in different modes. The ratio of the length of the jet to the length of the gap L serves as the beginning of the decay mode. It was determined that the ratio of the length of the jet to the length of the gap of the canvas when reaching 1 can be a reasonable criterion for evaluating the determination of the limits of the spraying mode. For a good spraying (for example, tearing of the web), small values of the ratio of the length of the jet to the length of the tearing of the web are necessary. This is achieved due to low surface tension, high gas density, high injection pressure (velocity) and large nozzle exit angles. The obtained results can be used for the design of sprayers and their modes of operation.

Cost-Effectiveness of Acaricide Application Methods against Heartwater Disease in South Africa

In an economic sense, heartwater disease is the most important tick-borne disease faced by South African livestock farmers. Methods to control the disease vary among farmers, and the preferred method depends on the prevalence of the disease in a specific area. The cost-effectiveness of different acaricide prevention methods against heartwater disease has not yet been determined amongst South African livestock producers. The study’s objective was to determine the cost-effectiveness of acaricide prevention methods used against heartwater disease in South Africa. Data used for this study were collected through a survey and structured questionnaires from 272 commercial livestock farmers in South Africa. Cost-effectiveness analyses were done on the spray, plunge, and pour-on acaricide application methods. For sheep and cattle, the plunge method proved to be the most cost-effective in all provinces of South Africa. In goats, pour-on acaricide application was the most cost-effective. The study recommends that extension activities provide farmers with information with which to choose the most appropriate acaricide application for the effective and sustainable control of heartwater disease.

Choice response of the olive fruit fly, Bactrocera oleae, to various bait/insecticide combinations: hydrolyzed proteins or ammonium salts?

Key to the success of the ground bait spray application method (‘attract and kill’) against Bactrocera oleae is to effectively suppress its population by inducing good levels of attraction and stimulate flies to ingest a lethal dose of the toxicant. A 2-year long field bioassay (fly captures to sticky panels) was developed to evaluate the exposure and response of olive flies to hydrolyzed protein based and ammonium salt baits in combination with various insecticides. A significantly higher attractive response of fruit flies was recorded in the case of the protein Entomella/phosmet combinations among protein bait/combination. Though next year, an enhanced attractive effect and a longer residual activity of ammonium salts compared to the tested protein to the olive fruit fly was clearly demonstrated. Especially in the case of beta-cyfluthrin mixed with ammonium salts, the mean number of captured flies were at least 3 to 11-fold (depending on the salt) higher compared to the respective protein-containing mixture baits instead of the organophosphate phosmet. Ammonium salts can successfully replace proteins in bait sprays.

The use of the Hazard Quotient approach to assess the potential risk to honeybees (Apis mellifera) posed by pesticide residues detected in bee‐relevant matrices is not appropriate

Pesticide residue data for pollen and nectar are valuable for characterizing realistic exposure of pollinators, e.g. from agricultural crops, flowering margins. Interpretation of residues relies on comparing exposure with toxicity and the Hazard Quotient (HQ) is widely utilized. However, the HQ (threshold of concern 50) was only validated for foliar sprays, based on application rate as a proxy for exposure, not measured residues in bee-relevant matrices. A review of the literature showed a range of HQ approaches and thresholds of concern used to assess non-foliar applications and residues detected in bee-relevant matrices, mostly pollen. The use of the HQ thresholds to assess risks associated with residue data or non-foliar spray application methods is not validated, does not reflect realistic exposure and the conclusions reached differ substantially from current risk assessment approaches. Re-evaluation of residue data from the first published use of the concentration-based HQ (2013) and a recent paper (2021) reduced the proportion of pesticides where a conclusion of potential risk was reached from 30 to 7% and 28% to 3-6%, respectively. An understanding of the applicability of the selected risk assessment approach to the available residue data is needed to enable robust conclusions to be drawn on the potential risk to bees. Use of the HQ approach to assess the risk posed by application methods other than foliar sprays or residues in nectar and pollen is likely to result in unreliable conclusions. An alternative approach should be used to assess the significance of measured residues.

A Comparison of Ground-Based Air-Blast Sprayer and Aircraft Application of Fungicides to Manage Scab in Tall Pecan Trees.

Pecan scab (caused by Venturia effusa) is a destructive disease of pecan in the southeastern United States. Susceptible cultivars must be sprayed with fungicide every 10 to 21 days to ensure yield and kernel quality. Fungicide is most often applied using large orchard air-blast sprayers. Pecan trees grow tall, and air-blast sprays result in a gradient in spray deposition and consequently of scab. Aerial fungicide application is also practiced. Disease distribution and spray deposition of the two methods have not been compared but will provide information aiding decisions on spray application methods. We compared air-blast, aerial, and air-blast + aerial applications for efficacy controlling scab at five heights in the canopy of 25-m cultivar Schley pecan trees. There was a negative relationship between scab severity and height in control trees, a positive linear relationship with height in air-blast treated trees, and a generally negative linear relationship between scab severity and height in aerially treated trees. Air-blast + aerial treatments resulted in low severity of scab at all heights. Spray deposition on water-sensitive cards indicated a declining gradient with height using an air-blast sprayer, whereas aerial applications resulted in a low deposition at all sample heights. Air-blast sprays tended to result in less good control at heights >12.5 m, and aerially treated trees at ≤7.5 m. The results provide insight into the efficacy and advantages of these methods for applying fungicide to control scab in tall pecan trees; further research is needed to better understand the impact of frequency and timing of these two methods.

Wide area spray of bacterial larvicide,Bacillus thuringiensis israelensisstrain AM65-52, integrated in the national vector control program impacts dengue transmission in an urban township in Sibu district, Sarawak, Malaysia.

Several sites, Z-7L, Z-5 and Z-14, in Sibu district, Sarawak, Malaysia, experienced intense dengue transmission in 2014 that continued into 2015. A pilot study with Bacillus thuringiensis israelensis (Bti) to control Aedes aegypti (L.) and Ae. albopictus (Skuse) was evaluated in Z-7L, a densely populated site of 12 ha. Bti treatments were conducted weekly from epidemiology week (EW) 24/2015 for 4 weeks, followed by fortnight treatments for 2 months, in addition to the routine control activities. Bti was directly introduced into potable containers and the outdoor artificial and natural containers were treated via a wide area spray application method using a backpack mister. Aedes indices significantly reduced during the treatment and post treatment phases, compared to the control site, Z-5 (p<0.05). A 51 fold reduction in the incidence rate per 100,000 population (IR) was observed, with one case in 25 weeks (EW 29–52). In Z-5 and Z-14, control sites, a 6 fold reduction in the IR was observed from EW 29–52. However, almost every week there were dengue cases in Z-14 and until EW 44 in Z-5. In 2016, dengue cases resurfaced in Z-7L from EW 4. Intensive routine control activities were conducted, but the IR continued to escalate. The wide area Bti spray misting of the outdoor containers was then included from EW 27 on fortnight intervals. A 6 fold reduction in IR was observed in the Bti treatment phase (EW 32–52) with no successive weekly cases after EW 37. However, in the control sites, there were dengue cases throughout the year from EW 1–52, particularly in Z-14. We feel that the wide area Bti spray application method is an integral component in the control program, in conjunction with other control measures carried out, to suppress the vector population in outdoor cryptic containers and to interrupt the disease transmission.

Herbicide Resistant Weeds

Herbicide performance is a complex issue that is influenced by many factors. These include spray coverage, application method, herbicide rate, environmental conditions, and weed size, to name a few. Poor or incomplete control may also be due to the ability of a weed to tolerate a particular herbicide. Herbicide tolerance is the inherent ability of a species to survive following a herbicide treatment. There was no selection to make the plant tolerant; it simply possesses a natural tolerance. This document is SS-AGR-243, one of a series of the Agronomy Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date December 2005.

&lt;p class="Body"&gt;Effects of cypermethrin, chlorpyrifos and piperonyl butoxide-based pour-on and spray acaricides on controlling the tick Rhipicephalus microplus

The objective of the study was to investigate the efficacy of cypermethrin, chlorpyrifos and piperonyl butoxide based pour-on and spray acaricides for the control of Rhipicephalus microplus in a naturally infested cattle herd. Fifty eight male Brangus cattle in the rearing phase were divided into treated (28) and untreated (30) groups. The treated group was subdivided in treated with a pour-on acaricide (13) and treated with a spray acaricide (15). Every 18 days, tick counts, acaricide treatment, weighing and clinical observation were performed on the animals, totaling four evaluation time points. The adult immersion tests were used for in vitro analysis of the study population to different chemical bases was assessed for primary results. Tick counts were separately compared between groups at each time point using the Kruskal-Wallis and Wilcoxon tests. Significantly fewer number of ticks were observed on the treated group compared to control group and also on the sprayed subgroup compared to pour-on subgroup (p&lt;0.05). Our results indicate that the chemical treatment evaluated directly affects the number of ticks parasitizing animals and that products employing a spray application method may be more effective in controlling cattle ticks.

Herbicidal control of bridal creeper (Asparagus asparagoides) in an ecologically sensitive environment

Asparagus asparagoides (bridal creeper) is a highly invasive noxious environmental weed in southern Australia. It poses a severe threat to biodiversity and conservation in temperate natural ecosystems. Pterostylis arenicola, a threatened terrestrial orchid endemic to South Australia, is directly imperilled by this weed in most of its remnant populations. The coincident growth phenologies of orchid and weed make for an ecologically sensitive environment when considering methods of weed control or eradication. To minimise impact on the orchid and its ecosystem, this paper examines the efficacy of herbicide application for A. asparagoides control using the weed wiping technique, comparing it to the conventional spray application method. The most prolonged control of A. asparagoides was achieved after a single wipe-application of 1.5 g a.i. (active ingredient) L−1 metsulfuron methyl, either alone or in combination with 120 g a.i. L−1 glyphosate, both treatments giving significantly better weed control five years after treatment than comparable spray applications. An investigation of the effect of glyphosate on cultures of the mycorrhizal fungus isolated from P. arenicola indicated a significant decline in mycelial growth with increasing herbicide concentration over the range 0.5–3.0 kg a.i. ha−1. These results provide further incentive for the use of ecologically sensitive herbicide application techniques, such as weed wiping, in areas of high conservation concern.

Performance of Precision Mobile Drip Irrigation in the Texas High Plains Region

Mobile drip irrigation (MDI) technology adapts driplines to the drop hoses of moving sprinkler systems to apply water as the drip lines are pulled across the field. There is interest in this technology among farmers in the Texas High Plains region to help sustain irrigated agriculture. However, information on the performance of this system and its benefits relative to common sprinkler application technologies in the region are limited. A two-year study was conducted in 2015 and 2016 to compare grain yields, crop water use (ETc) and water use efficiency (WUE) of corn (Zea Mays L.) irrigated with MDI, low elevation spray application (LESA) and low energy precision application (LEPA) methods. Irrigation amounts for each application method were based on weekly neutron probe readings. In both years, grain yield and yield components were similar among application treatment methods. Although WUE was similar for the MDI treatment plots compared with LEPA and LESA during the wet growing season (2015), MDI demonstrated improved WUE during the drier year of 2016. Additional studies using crops with less than full canopy cover at maturity (sorghum and cotton) are needed to document the performance of MDI in the Texas High Plains region.

Improved demethylation in ecological epigenetic experiments: Testing a simple and harmless foliar demethylation application

AbstractExperimental demethylation of plantDNAenables testing for epigenetic effects in a simple and straightforward way without the use of expensive and laboriousDNAsequencing. Plants are commonly demethylated during their germination with the application of agents such as 5‐azacytidine (5‐azaC). However, this approach can cause unwanted effects such as underdeveloped root systems and high mortality of treated plants, hindering a full comparison with untreated plants, and can be applied only on plant reproducing by seeds. Here we test a simple alternative method of plant demethylation designed to overcome the shortcomings of the germinating method.We compared a novel method of demethylating plants, based on periodical spraying of 5‐azaC aqueous solution on established seedlings, with the previous method in which seeds were germinated directly in 5‐azaC solution. We quantified the amount of methylatedDNAand measured various aspects of plant performance. Also, we demonstrated its applicability in ecological epigenetic experiments by testing transgenerational effects of plant–plant competition.We found that the spray application had similarDNA‐demethylating efficiency than the germination method, particularly in the earlier phases of plant development, but without unwanted effects. The spray application method did not reduce plant growth and performance compared to untreated plants, as opposed to the traditional method which showed reduced growth. Also, the spray application method equalized the epigenetically modified plant features of seedlings coming from plants grown under competition and plants growing without competition, demonstrating its application in ecological epigenetic experiments.We conclude that regular spraying of 5‐azaC solution onto established seedlings surpassed the germination‐in‐solution method in terms of vigour and fitness of treated plants. This novel method could thus be better suited for experimental studies seeking valuable insights into ecological epigenetics. Furthermore, the spray method can be suitable for clonal species reproducing asexually, and most importantly, it opens the possibility of community‐level experimental demethylation of plants.

Aerial electrostatic spray deposition and canopy penetration in cotton

Daylight visible fluorescent dye (10% v/v) mixed with water was aerially applied on mature field cotton with electrostatic and rotary atomizer nozzles. The spray rates for the electrostatic and rotary atomizer nozzles were 9.4 and 28 L/ha, respectively. Images of spray droplets on cotton leaves were digitally analyzed with ImageJ software. Charged spray cloud increased deposition nearly two to three times on adaxial and abaxial surfaces, respectively, of top canopy leaves compared to uncharged spray. Canopy penetration of the spray into the lower layers of the plant foliage was unaffected by spray application method.

Refreshing bait spots in an olive orchard for the control of Bactrocera oleae (Diptera: Tephritidae)

Key to the success of the ground bait spray application method (‘attract and kill’) against Bactrocera oleae (Gmelin) is the long-term maintenance of the attractiveness of the trophic attractant as well as the toxicity of the active ingredient included in a bait spot. Large-scale field trials were conducted in olive orchards on Crete to estimate the quantity of alpha-cypermethrin applied as a bait spot on olive leaves as well as lab experiments to evaluate its residual effectiveness against the fly over time. Alpha-cypermethrin remained effective in olive tree canopies for at least 2 months (residues of alpha-cypermethrin on olive leaves were detected 7 days after the first and second bait spray applications and ranged from 5 to 7 and 16 to 19 mg/kg, respectively, as indicated by GC-MS/MS analysis, while the recorded adult mortality was >55% for at least 20 weeks following spray application). Moreover, additional protein-only sprays to specific parts of the olive canopy that had been previously sprayed with a bait spraying solution (alpha-cypermethrin plus hydrolysed protein at 75% w/w) significantly reduced olive fruit fly captures in treated plots compared to the captures recorded in plots with the classical bait spray. The percentages of live infestation of B. oleae were very low (<2%) and did not differ significantly between the two tested practices. The benefits of the reduced use of pesticides in the management of this pest are discussed.

Evaluation of spray application methods for navel orangeworm control in almonds.

Gear Up/Throttle Down (GUTD) and Inward Only strategies represent potential alternatives to conventional airblast applications to reduce spray drift. This study evaluates Inward Only and a modified version of GUTD in almonds, the largest US tree crop, at the recommended hull split treatment timing for control of navel orangeworm (NOW), the key almond insect pest. Conventional treatment produced the most drift (15.6% of total bifenthrin load), while the GUTD and Inward Only treatments produced only 7.6 and 9.7% respectively. For all methods, 92-94% of the drift was found in the first 15.2 m downwind of the orchard. NOW control was lower for the Inward Only treatment compared with the GUTD and conventional treatments. NOW control was consistently lower at 4.88 m height relative to 2.44 m in all treatments, reflecting the reduced deposition higher in the tree canopy recorded in deposition samples. While Inward Only treatments reduced spray drift relative to the conventional application method, poorer control of NOW, the key insect pest of almonds, in the Inward Only treatment would likely limit its voluntary use by growers. However, GUTD holds promise for use at the hull split treatment timing to address spray drift. © 2016 Society of Chemical Industry.

In vitro growth-inhibitory effect of Brazilian plants extracts against Paenibacillus larvae and toxicity in bees.

American foulbrood (AFB) is a serious worldwide spreading disease in bees caused by Paenibacillus larvae. Plants extracts are known to decrease or inhibit the growth of these bacteria. The purpose of this study was to evaluate the antimicrobial activity of Calendula. officinalis, Cariniana domestica, and Nasturtium officinale extracts against the P. larvae and to evaluate the toxicity of the extracts in bees. In vitro activity against P. larvae of the extracts was evaluated by micro dilution method and the minimal inhibitory concentrations (MICs) were also determined. The concentrations used in the toxicity test were established based on the MIC values and by the spraying application method. The P. larvae was susceptible to the evaluated crude extract of C. officinalis and N. officinale. To C. domestica, only the ethyl acetate (EtAc) fraction and n-butanol (BuOH) fractions had activity against P. larvae. Toxicity analysis in bees showed no toxicity for N. officinale crude extract and for C. domestica BuOH fraction during 15 days of treatment, however, some deaths of bees occurred during the first three days of treatment with C. officinalis and C. domestica EtAc fraction. The results with these species were firstly described and showed that N. officinale crude extract and C. domestica BuOH fraction both presented not toxic effects in the concentration tested by the spraying application method, and can be a useful alternative for treatment or prevention of AFB.

The Effect of Sample Height on Spray Coverage in Mature Pecan Trees.

Pecan scab (caused by Fusicladium effusum) is the most damaging disease of pecan in the southeastern United States. Large air-blast sprayers for orchards are used to apply fungicide to control the disease but little quantitative information exists on the spray coverage achieved in the canopy of these trees. A series of experiments using water-sensitive spray cards to record spray coverage (percent area) at different heights and locations up to 15 m in the canopy of pecan trees showed a significantly greater percentage of card area covered at the lowest sample height when compared with the highest sample height. At the lowest height (5 m), spray coverage on individual cards ranged from 4.7 to 73.5% and, at the highest sample height (15 m), spray coverage ranged from 0.02 to 9.5%. In general, there was little significant difference in spray card coverage up to at least 10 m but, at 12.5 and 15 m, there was significantly less spray coverage compared with the coverage at 5 m. Regression analysis indicated a consistent linear relationship between sample height in the tree and the percent area covered. When spray cards were positioned at different heights without possible interference from pecan limbs and foliage, similar effects of sample height on spray coverage were noted. Wind speed measurements showed that air movement declined rapidly with distance from the sprayer fan. Whereas, at 2 m from the fan, wind speeds were approximately 26 m s-1, by 10 m, speeds had declined to 2 to 4 m s-1. At distances >12 m, wind speed was approaching ambient air movement of about 1 to 3 m s-1. Although aerial application resulted in numerically greater spray coverage at sample heights >10 m, it was not significant even though a weak linear relationship (R2 = 0.21 to 0.25) suggested an effect of height. Characterizing and understanding pesticide spray coverage in pecan will allow us to discern limits imposed by existing technology, and provide the basis for improving spray application methods (or tree management) for more efficacious disease control.

Development of a new method to predict the maximum spread factor for shear thinning drops

Drop impact on a solid surface has obtained attention for a variety of industrial processes, such as application of edible coatings by spray application method. In the present work, drop impact behavior of edible coating formulations (ECF) based on gelatin, glycerol and cellulose nanofiber on banana and eggplant epicarps was studied. Drops of ECF were generated from a syringe pump system-controlled, for images a high speed camera was used and the maximum spread diameter was determined with ImageJ program. The models reported in the literature do not predict experimental data of maximum spread factor, because the EFC behave as non-Newtonian fluid, so it was necessary to modify these models by introducing an apparent viscosity at average shear rate (effective viscosity). The inclusion of an effective viscosity significantly improves the prediction of the evaluated models.

Use of Selected Herbicides and Application Methods for Tolerance to Tifton 85 Bermudagrass [Cynodon dactylon (L.) Pers.

Aims: To evaluate forage tolerance of Tifton 85 bermudagrass to selected pasture herbicides using two application methods: broadcast (BRD) and individual plant treatments (IPT). Study Design: A randomized complete block design was employed with four replications. Place and Duration of Study: Trials were conducted during the 2006 and 2007 growing seasons near Thrall, Texas, (30.35 o N, 97.17 o W). Methodology: Two spray application methods (BRD and IPT) were compared when using selected herbicides for bermudagrass tolerance. Herbicides evaluated by BRD included picloram plus fluroxypyr, picloram plus fluroxypyr plus metsulfuron-methyl, triclopyr, triclopyr plus fluroxypyr, triclopyr plus metsulfuron-methyl, triclopyr plus fluroxypyr plus metsulfuron-methyl, and metsulfuron-methyl plus dicamba plus 2,4-D. Herbicides evaluated by IPT included triclopyr, triclopyr plus fluroxypyr, and picloram plus fluroxypyr. Bermudagrass injury, yield, and crude Original Research Article Janak et al.; AJEA, 8(5): 289-298, 2015; Article no.AJEA.2015.172 290 protein content were evaluated for application method and herbicide. Results: Rainfall after herbicide application in 2006 was 67% below normal while in 2007 rainfall was 350% above normal. No bermudagrass necrosis or growth reduction were noted in 2006. Triclopyr plus fluroxypyr applied IPT was the only treatment to decrease Tifton 85 dry matter yield at the first harvest, with no effect observed at the second. In 2007, necrosis was greatest with triclopyr plus fluroxypyr applied BRD while triclopyr plus fluroxypyr and triclopyr plus fluroxypyr plus metsulfuron-methyl applied BRD and triclopyr applied IPT caused the greatest growth reduction. Triclopyr and triclopyr plus fluroxypyr applied BRD or IPT and triclopyr plus fluroxypyr plus metsulfuron-methyl applied BRD decreased dry matter yield at the first harvest while only triclopyr alone applied IPT reduced yield at the second. Conclusions: The recurring bermudagrass stunting and yield reduction with triclopyr is consistent with previous forage tolerance research. Metsulfuron methyl plus dicamba plus 2,4-D was the only treatment that exhibited little or no injury, growth reduction, or yield reduction at any time. Producers need to be aware of potential injury issues with triclopyr.

Potential Use of Buddleja Thyrsoides for the Control and Prevention of American Foulbrood Disease in Honey Bees

Abstract Paenibacillus larvae is the causative agent of American Foulbrood (AFB ), a severe disease that affects the larvae of the honeybees. The use of plant extracts are considered to be an alternative way of controlling the disease. In this study, the in vitro antimicrobial activity of Buddleja thyrsoides Lam. against the Paenibacillus species, including P. larvae, was evaluated. In Mueller-Hinton broth, the minimal inhibitory concentration (MI C) was assessed using the microdilution method. All Paenibacillus species were sensitive to the crude extract and the fractions of B. thyrsoides. The ethyl acetate (EA ) fraction showed a better result with MI C values of 1.68 - 3.36 mg/mL, followed by butanolic (BU) (MI C = 2.18 - 6.54 mg/mL), dichloromethane (DCM) (7.40 - 14.80 mg/mL), and crude extract (CE) (7.51 - 16.90 mg/mL). The toxic effect of the CE and fractions of B. thyrsoides against bees were also evaluated using the spraying application method with the same concentrations of MI Cs. Bee mortality was evident in treatment with DCM fractions only, while CE, EA , and BU extracts showed no toxic effects after 15 days of observation. Furthermore, phenolic acids, tannins, and flavonoids were identified and quantified by highperformance liquid chromatography (HPLC), and may be partially responsible for the antimicrobial properties observed. These results show, for the first time, that B. thyrsoides might be a natural alternative for the prevention/control of AFB .

Antimicrobial activity of tea tree oil nanoparticles against American and European foulbrood diseases agents

Paenibacillus larvae and Melissococcus plutonius are the primary bacterial pathogens of honeybees and the causative agents of American and European foulbrood disease (AFB and EFB) respectively. Such diseases have been gaining importance since there are few therapeutic options beyond the reporting of microorganisms resistant to conventional antibiotics. Due to the inefficiency and/or low efficacy of some antibiotics, researches with nanotechnology represent, possibly, new therapeutic strategies. Nanostructured drugs have presented some advantages over the conventional medicines, such as slow, gradual and controlled release, increased bioavailability, and reduced side-effects, among others. In this study, in vitro antimicrobial activity of tea tree oil (TTO) nanoparticles against Paenibacillus species, including P. larvae and M. plutonius strains was evaluated. Minimal inhibitory concentration (MIC) in Mueller–Hinton or KSBHI broth by the microdilution method was assessed. TTO registered MIC values of 0.18–6.25%, while the MIC values obtained for the TTO nanoparticle were of 0.01–0.93%. The possible toxic effect of TTO and TTO nanoparticle has been assessed by the spraying application method in the concentrations higher than the MICs. Bee mortality was evident only in treatment with TTO and the TTO nanoparticles show no toxic effects after 7days of observation. Our results showed for the first time that TTO nanoencapsulation presented a high activity against Paenibacillus species and M. plutonius strains showing that the use of nanotechnology may represent one alternative way for the treatment or prevention of AFB and EFB.