Efficacy of low-dose fipronil bait against blacklegged tick (Ixodes scapularis) larvae feeding on white-footed mice (Peromyscus leucopus) under simulated field conditions.

BACKGROUND: Lyme disease, caused primarily by Borrelia burgdorferi sensu stricto, is the most prevalent vector-borne disease in the United States. Treatment of rodent pathogen reservoirs with an oral acaricide may suppress the production of infected host-seeking ticks posing a risk for human infection. A previous study showed that an oral fipronil bait effectively controlled larval Ixodes scapularis ticks on white-footed mice (Peromyscus leucopus) up to 15 days post-bait exposure. The present study expands upon this finding by exposing group-housed white-footed mice to fipronil bait under simulated field conditions prior to tick infestation. METHODS: Mice (n = 80) were housed in groups of 10 within large enclosures and offered a choice between fipronil bait within a commercial bait station and an alternative diet. The mice were assigned to two treatment groups and two control groups to undergo bait exposure durations of either 24 h (reduced) or 168 h (extended). Groups were further differentiated by the time point post-bait exposure when larval ticks were applied to mice within feeding capsules (reduced day 1, day 15; extended day 21, day 35). For 4 days post-tick introduction, attached larvae were observed by microscopy and replete larvae were recovered. Replete larvae were monitored for molting success. Plasma was collected from all treatment group mice to obtain fipronil plasma concentrations (CP). RESULTS: The fipronil bait (0.005% fipronil) was palatable and controlled larval ticks on white-footed mice when presented under simulated field conditions. Efficacy in preventing attached larvae from feeding to repletion was 100% (day 1), 89.0% (day 15), 85.8% (day 21), and 75.2% (day 35). When also considering molting success, the fipronil bait prevented 100% (day 1), 91.1% (day 15), 91.7% (day 21), and 82.5% (day 35) of larvae attaching to mice from molting. The mean CP per mouse was 191.5 ng/ml (day 1), 29.4 ng/ml (day 15), 10.6 ng/ml (day 21), and 1.0 ng/ml (day 35). CONCLUSIONS: The results suggest that fipronil bait will be consumed by white-footed mice in the presence of an alternative diet, and effectively control larval ticks on treated mice. A field trial is needed to confirm the results of this study. Low-dose fipronil bait may provide a cost-effective means of controlling blacklegged ticks to be integrated into tick management programs.

Integrated Tick Management in South Central Wisconsin: Impact of Invasive Vegetation Removal and Host-Targeted Acaricides on the Density of Questing Ixodes scapularis (Acari: Ixodidae) Nymphs.

As tick-borne disease incidence increases and pathogens expand into new areas, the need for effective tick management strategies is paramount. In this 5-yr study (2014-2018) conducted in south central Wisconsin, we assessed whether an integrated tick management approach, deployed during peak tick activity (May-August), was more effective at reducing black-legged ticks (Ixodes scapularis Say (Ixodida: Ixodidae)), than individual interventions. Using a factorial design, invasive vegetation removal (Amur honeysuckle, Lonicera maackii Ruprecht (Dipsacales: Caprifoliaceae) and common buckthorn, Rhamnus cathartica Linnaeus (Rosales: Rhamnaceae)) was coupled with deployments of permethrin-treated cotton nesting materials (tick tubes) that target the white-footed mouse (Peromyscus leucopus Rafinesque (Rodentia: Cricetidae)). Results show that the probability of encountering a larval tick by drag sampling was unaffected by treatments at the cumulative 5-yr level. However, vegetation removal significantly reduced larval encounters in 2014, 2015, and 2018, by 33%, 57%, and 61% respectively, and reduced the density of questing nymphal (DON) ticks by 45% in 2015 compared to controls. Despite the limited effect on DON, vegetation removal significantly reduced the cumulative 5-yr density of Borrelia burgdorferi sensu stricto infected nymphs (DIN) (70%) compared to controls as a result of decreased nymphal infection prevalence. Sites treated with tick tubes had lower DIN (66%) and DON (54%) across the study and nymphs were reduced every year following the initial year of deployment compared to controls. Combining treatments did not further reduce DIN or DONs. We conclude that long-term integration of tick tubes with invasive vegetation removal does not provide additional benefit over individual treatments alone.

Spray and Pour-On Acaricides Killed Tennessee (United States) Field-Collected Haemaphysalis longicornis Nymphs (Acari: Ixodidae) in Laboratory Bioassays.

Haemaphysalis longicornis Neumann (Asian longhorned tick) is an exotic and invasive tick species presenting a health and economic threat to the United States (U.S.) cattle industry due to its ability to transmit pathogens and infest hosts in large numbers. The objective of this study was to evaluate available products at causing H. longicornis mortality in a laboratory bioassay. The efficacy of products was evaluated at label rates using H. longicornis nymphs collected from a cattle farm in eastern Tennessee in two different bioassays (spray or dip) against untreated controls. After exposure, ticks were transferred to clean petri dishes and checked for mortality at 0, 1, 2, 3, 4, 21, 24, and 48 h post exposure. No mortality occurred in the untreated controls, whereas all treated ticks were dead within 24 h of exposure (P < 0.0001). These findings support the hypothesis that currently available spray and pour-on products are effective at causing H. longicornis mortality. We conclude that these acaricides can be used as a component to prevent H. longicornis dispersal and for control in the U.S.

Identification of a non-host semiochemical from miniature pinscher, Canis lupus familiaris, that repels Rhipicephalus sanguineus sensu lato (Acari: Ixodidae).

It is already known that the beagle breed of domestic dogs produces semiochemicals capable of repelling the brown dog tick, Rhipicephalus sanguineus sensu lato (s.l.). With a view to discovering new non-host semiochemicals as tick repellents, we compared the semiochemicals produced by a putative tick-resistant breed of dog, miniature pinscher, with known tick-resistant (beagle) and tick-susceptible (English cocker spaniel) breeds. Two non-host compounds produced by beagles, i.e. 2-hexanone and benzaldehyde, were shown to be present in samples collected from all three breeds. Furthermore, two compounds, 6-methyl-5-hepten-2-one and 1,2,4-trimethylbenzene, were found in higher amounts in samples collected from miniature pinscher dogs. The mean amounts of benzaldehyde, 2-hexanone and 1,2,4-trimethylbenzene were similar for beagles and miniature pinschers (P > 0.05) and higher than the means observed for cocker spaniels (P < 0.05), whereas the mean amount of 6-methyl-5-hepten-2-one produced by miniature pinschers was significantly higher (P < 0.05) than for the other breeds of dogs. In Petri-dish assays with adult R. sanguineus s.l., 6-methyl-5-hepten-2-one was repellent for all observation periods evaluated for the two highest concentrations (0.100 and 0.200 mg.cm-2, P < 0.01). The obtained results support our hypothesis that miniature pinschers are a tick-resistant dog breed and agree with previous observations of miniature pinschers being the breed least parasitized by ticks. Furthermore, the non-host semiochemical 6-methyl-5-hepten-2-one has potential to be developed for use as a repellent for the protection of susceptible dogs from R. sanguineus s.l. ticks.

Chitin increases drying survival of encapsulated Metarhizium pemphigi blastospores for Ixodes ricinus control.

Ticks, like Ixodes ricinus, have negative impacts on human and animal health in Germany and worldwide, with almost no specific scientifically proven biological control agent commercially available. Biological control agents containing entomopathogenic fungi present many advantages over chemical acaricides but usually high doses of aerial conidia (1013-1014 conidia/ha) are required to control arthropod pests in the field. A suitable formulation containing nutrients not only makes sensitive blastospores applicable but also functions as a microfermenter to multiply the biomass and thus significantly reduce the required application dosage. For this approach, Metarhizium pemphigi X1c blastospores were encapsulated in calcium alginate beads with granular corn starch or chitin powder as nutrients to ensure formation of aerial conidia on the surface and were then dried. The highest concentration was obtained with moist beads containing chitin (4.68 ±â€¯0.71∙107 conidia∙bead-1). The highest drying survival was also obtained with chitin as the additive (14.7 ±â€¯2.18%). Newly formed aerial conidia of all formulations showed high virulence and caused 100% mortality of I. ricinus nymphs. Altogether, this study paves the way for a lower dose and cost-effective application of blastospores for the control of above ground arthropod pests.

Woodchip borders at the forest ecotone as an environmental control measure to reduce questing tick density along recreational trails in Ottawa, Canada.

Recent studies have highlighted the occurrence and distribution of Ixodes scapularis ticks infected with Borrelia burgdorferi sensu stricto (s.s.) around the city of Ottawa, Ontario, Canada, and the need for strategies to mitigate the risk of human exposure and infection. We conducted a field study from July to October 2018 to examine the effectiveness of ecotonal woodchip borders as an environmental control method to suppress the density of host-seeking ticks along recreational trails in Ottawa. We used an experimental design with ten 100-m trail replicates randomized to intervention or control groups, and monitored questing tick density at weekly intervals in mid-summer and early fall. We compared questing tick density between woodchip-treated and untreated trails using a mixed-effects Poisson regression model. Of the 138 I. scapularis ticks collected, there were 86 adult and nymphal ticks, 37 (43 %) of which were positive for B. burgdorferi s.s. A total of 58 Haemaphysalis leporispalustris were also collected. Mean combined adult and nymphal I. scapularis density was 1.15 (1.40 standard deviation; SD) per 100 m in the control group compared to 0.28 (0.56 SD) per 100 m in the intervention group, reflecting a 75 % reduction in questing tick density on trail replicates treated with woodchip borders (p < 0.001). An effect of the intervention was observed in both sampling periods. This study indicates that woodchip borders may be an effective strategy to suppress questing tick density along trail margins where recreational trail users are more active, thereby reducing the likelihood of tick encounters.

Innovative way to dispense pheromones for off-host control of Rhipicephalus sanguineus sensu lato ticks.

Vapour patches dispensing pheromones were evaluated as lures to increase the attractiveness of sticky tick traps for Rhipicephalus sanguineus sensu lato (s.l.). Sex pheromone (SP), assembly pheromone (AP) and a combination of SP + AP at optimal concentrations were impregnated in vapour patches. The responses of the different stages of R. sanguineus s.l. (i.e. larvae, nymphs and adults) to the pheromones were evaluated using a Petri dish bioassay. The impregnated vapour patches were retained as such for a period of two mo and their efficacy was reassessed. In a subsequent field trial, pheromone impregnated vapour patches were placed as lures in bamboo (Bambusa vulgaris) sticky traps designed for the control of ticks in dog kennels. In vitro AP impregnated vapour patches were effective in attracting the different life stages of R. sanguineus s.l. whereas SP was effective in attracting the unfed and fed male stages of R. sanguineus s.l. The field trial revealed that questing and engorged larvae, nymphs and females of R. sanguineus s.l. were attracted more towards AP impregnated vapour patches than SP and AP + SP impregnated vapour patches. Fed and unfed male ticks were lured effectively by SP alone. The combination of SP + AP revealed no potent additive or synergistic effect.

Ability of Two Commercially Available Host-Targeted Technologies to Reduce Abundance of Ixodes scapularis (Acari: Ixodidae) in a Residential Landscape.

Host-targeted technologies provide an alternative to the use of conventional pesticide applications to reduce the abundance of Ixodes scapularis Say, the vector for an array of tick-associated human diseases. We compared the ability of Damminx Tick Tubes (Damminix) and SELECT Tick Control System (Select TCS) bait boxes to control host-seeking I. scapularis nymphs in a wooded residential environment. Small mammals accepted and used Select TCS bait boxes with greater frequency compared to Damminix tubes over the course of the 2-yr trial. Nymphal tick infestation prevalence and intensity on captured mice and chipmunks provided no conclusive evidence of a treatment effect during May-June of both years. However, both treatments had a measurable effect on larval tick burdens in July-August and the magnitude of the effect was greater at the Select TCS-treated area and reflected the fact that Select TCS effectively treated chipmunks, while Damminix did not. Deployment of Damminix resulted in 27.6 and 20.3% control of questing nymphs in treated areas at 1 yr and 2 yr postintervention, while Select TCS bait boxes provided 84.0 and 79.1% control, respectively. The economics of residential tick control using these products in wooded residential landscapes is discussed.

Season-long control of flea and tick infestations in a population of cats in the Aeolian archipelago using a collar containing 10% imidacloprid and 4.5% flumethrin.

Cats that have outdoor access are highly exposed to ticks, fleas, mites and flying insects, though the risk to become infested by arthropods is less perceived in cats than in dogs. This has resulted in fewer treatment and prevention options being available for cats than for dogs. A collar containing a combination of 10% imidacloprid and 4.5% flumethrin (Seresto®, Bayer Animal Health) is available for cats and licensed with claims against ticks and fleas for 7-8 months. Following the assessment of the efficacy of the collar against Leishmania infantum infection in privately owned cats living in the Aeolian archipelago, herein we report the efficacy of the collar in the treatment and prevention of tick and flea infestations in the same population of cats over a period of one year of observation. At the inclusion day (Study Day 0, SD 0), cats were visited and examined for ectoparasites (i.e., flea combing and tick thumb counts) and allocated to group 1 (G1; n=104; cats treated with Seresto® collar) or group 2 (G2; n=100; untreated controls) and further checked at SDs 210, 270 and 360 (study closure). At SD 0, G1 and G2 had a comparable percentage of cats infested by fleas (45.2% and 49.0%; χ2=0.164; P=0.6859) and ticks (6.7% and 14.0%; χ2=2.946; P=0.0861). The number of cats infested by fleas was reduced in G1, being 8.3%, 0% and 3.8% on SDs 210, 270 and 360, respectively, resulting in efficacies against fleas of 79.4%, 100% and 93.6% on SDs 210, 270 and 360. None of the cats in G1 was found infested by ticks after the application of the collar, whereas in G2 ticks were observed on 15.7%, 4.8%, 17.5% of the cats at the different follow up visits, leading to an overall efficacy against ticks of 100%. A total of 375 ectoparasites were collected from cats, being 249 fleas (six Ctenocephalides canis, 240 Ctenocephalides felis and three Nosopsyllus fasciatus) and 126 ticks (87 Ixodes ventalloi and 39 Rhipicephalus pusillus). Field data gathered herein confirm a high efficacy of the collar in the prevention of tick and flea infestations on cats. This is of great importance both for the primary role of fleas and ticks as blood feeding parasites and, more importantly, because of their role as vectors of pathogens causing diseases of veterinary and medical importance.

Nanoparticles as effective acaricides against ticks-A review.

Ticks serve as vectors of a wide range of infectious agents deleterious to humans and animals. Tick bite prevention is based to a large extent on the use of chemical repellents and acaricides. However, development of resistance in targeted ticks, environmental pollution, and contamination of livestock meat and milk are major concerns. Recently, metal, metal oxide and carbon nanoparticles, particularly those obtained through green fabrication routes, were found to be highly effective against a wide array of arthropod pests and vectors. We summarize current knowledge on the toxicity of nanoparticles against tick vectors of medical and veterinary importance. We also discuss the toxicity of products from botanical- and bacterial-based as well as classic chemical nanosynthesis routes, showing differences in bioactivity against ticks based on the products used for the fabrication of nanoparticles. Further research is needed, to validate the efficacy of nanoparticle-based acaricides in the field and clarify mechanisms of action of nanoparticles against ticks. From a technical point of view, the literature analyzed here showed little standardization of size and weight of tested ticks, a lack of uniform methods to assess toxicity and concerns related to data analysis. Finally, an important challenge for future research is the need for ecotoxicology studies to evaluate potential negative effects on non-target organisms and site contamination arising from nanoparticle-based treatments in close proximity of livestock and farmers.

Evaluation of Doxycycline-Laden Oral Bait and Topical Fipronil Delivered in a Single Bait Box to Control Ixodes scapularis (Acari: Ixodidae) and Reduce Borrelia burgdorferi and Anaplasma phagocytophilum Infection in Small Mammal Reservoirs and Host-Seeking Ticks.

A field trial was conducted on residential properties in a Lyme disease endemic area of New Jersey to determine the efficacy of Maxforce Tick Management System (TMS) bait boxes modified with doxycycline hyclate-laden bait to reduce the acarological risk of Lyme disease and the utility of galvanized steel shrouds to protect the bait boxes from squirrel depredation and ability to routinely service these devices. The strategy began with a 9-wk deployment against larvae followed by a 17-wk deployment against nymphs and larvae the second year. Passive application of fipronil reduced nymphal and larval tick burdens on small mammals by 76 and 77%, respectively, and nymphal tick abundance by 81% on treated properties. In addition, the percentage of infected small mammals recovered from intervention areas following treatment was reduced by 96% for Borrelia burgdorferi and 93% for Anaplasma phagocytophilum. Infection prevalence in host-seeking nymphal ticks for both B. burgdorferi and A. phagocytophilum were reduced by 93 and 61%, respectively. Results indicate that Maxforce TMS bait boxes fitted with doxycycline-impregnated bait is an effective means of reducing ticks and infection prevalence for B. burgdorferi and A. phagocytophilum in both rodent reservoirs and questing Ixodes scapularis Say ticks. The protective shroud allows the device to be routinely serviced and protect against squirrel depredation.

Comparison of novel and conventional methods of trapping ixodid ticks in the southeastern U.S.A.

Tick-borne disease surveillance and research rely on resource-effective methods for tick collection. This study compared the respective performances of several trapping methods in a mixed grassland-forest habitat in western Tennessee. To test for temporal differences in effectiveness, sites were sampled monthly (April-August 2013) using dry ice, dragging, flagging, sweep netting, carbon dioxide (CO2 ) dragging and CO2 flagging methods. To evaluate the effect of habitat on method effectiveness, four methods (dragging, CO2 dragging, CO2 flagging and dry ice) were compared in four habitat types (bottomland deciduous, upland deciduous, coniferous and grassland) in June 2014. In the temporal comparison, ticks were found to be most abundant in April and May, and there was a significant sampling period and method interaction, such that method effectiveness varied across sampling period. Sweep netting was significantly less effective than the other methods. In the habitat comparison, dry ice trap collections represented the most effective method in upland deciduous and coniferous habitats. Flagging using CO2 was significantly less effective than CO2 dragging and dragging in bottomland deciduous habitats. The success of the various collection methods did not differ significantly within grassland habitats. Overall, dry ice trapping and dragging were the most effective methods for tick collection across time and habitat.

Evaluation of a brushing machine for estimating density of spider mites on grape leaves.

Direct visual inspection and enumeration for estimating field population density of economically important arthropods, such as spider mites, provide more information than alternative methods, such as binomial sampling, but is laborious and time consuming. A brushing machine can reduce sampling time and perhaps improve accuracy. Although brushing technology has been investigated and recommended as a useful tool for researchers and integrated pest management practitioners, little work to demonstrate the validity of this technique has been performed since the 1950's. We investigated the brushing machine manufactured by Leedom Enterprises (Mi-Wuk Village, CA, USA) for studies on spider mites. We evaluated (1) the mite recovery efficiency relative to the number of passes of a leaf through the brushes, (2) mite counts as generated by the machine compared to visual counts under a microscope, (3) the lateral distribution of mites on the collection plate and (4) the accuracy and precision of a 10% sub-sample using a double-transect counting grid. We found that about 95% of mites on a leaf were recovered after five passes, and 99% after nine passes, and mite counts from brushing were consistently higher than those from visual inspection. Lateral distribution of mites was not uniform, being highest in concentration at the center and lowest at the periphery. The 10% double-transect pattern did not result in a significant correlation with the total plate count at low mite density, but accuracy and precision improved at medium and high density. We suggest that a more accurate and precise sample may be achieved using a modified pattern which concentrates on the center plus some of the adjacent area.

Evaluation of Four Bed Bug Traps for Surveillance of the Brown Dog Tick (Acari: Ixodidae).

The brown dog tick, Rhipicephalus sanguineus (Latrielle), can be a serious residential pest due to its unique ability, among ticks, to complete its lifecycle indoors. A single engorged and fertilized female tick can oviposit around 4,000 eggs, allowing indoor establishment to be rapid and easy to miss in early-stage infestations. Acaricide treatment is currently the primary method of control, but can be costly and can lead to the development of acaricide resistance in tick populations. Traps of various designs can be used to help monitor and manage populations of indoor pests, such as cockroaches and bed bugs, but there are currently no commercially available traps for use with brown dog tick infestations. This study included a comparison of four commercially available bed bug traps (NightWatch [BioSensory Inc., Putnam, CT], Bed Bug Beacon [PackTite, Fort Collins, CO], ClimbUp [Susan McKnight Inc., Memphis, TN], and Verify [FMC Corporation, Philadelphia, PA]) with regard to their efficacy in capturing brown dog ticks, and also compared tick attraction to ClimbUp traps baited with several stimuli including CO2. Significantly more ticks were captured and attracted to the NightWatch and CO2-baited ClimbUp traps than the other two trap models. The results suggest that bed bug traps may be useful in brown dog tick monitoring, and CO2 will likely be an important component of a trapping system employed in the future.

TickBot: a novel robotic device for controlling tick populations in the natural environment.

A semi-autonomous 4-wheeled robot (TickBot) was fitted with a denim cloth treated with an acaricide (permethrin™) and tested for its ability to control ticks in a tick-infested natural environment in Portsmouth, Virginia. The robot's sensors detect a magnetic field signal from a guide wire encased in 80m polyethylene tubing, enabling the robot to follow the trails, open areas and other terrain where the tubing was located. To attract ticks to the treated area, CO2 was distributed through the same tubing, fitted with evenly spaced pores and flow control valves, which permitted uniform CO2 distribution. Tests were done to determine the optimum frequency for TickBot to traverse the wire-guided treatment site as well as the duration of operation that could be accomplished on a single battery charge. Prior to treatment, dragging was done to determine the natural abundance of ticks in the test site. Controls were done without CO2 and without permethrin. TickBot proved highly effective in reducing the overall tick densities to nearly zero with the treatment that included both carbon dioxide pretreatment and the permethrin treated cloth. Following a 60min traverse of the treatment areas, adult tick numbers, almost entirely Amblyomma americanum, was reduced to zero within 1h and remained at or near zero for 24h. Treatments without CO2 also showed reduction of ticks to near zero within 1h, but the populations were no different than the control sections at 4h. This study demonstrates the efficacy of TickBot as a tick control device to significantly reduce the risk of tick bites and disease transmission to humans and companion animals visiting a previously tick-infested natural environment. Continued deployment of TickBot for additional days or weeks can assure a relatively tick-safe environment for enjoyment by the public.

Efficacy of slow-release tags impregnated with aggregation-attachment pheromone and deltamethrin for control of Amblyomma variegatum on St. Kitts, West Indies.

BACKGROUND: Amblyomma variegatum is an important cause of morbidity, mortality and economic losses in Africa and the West Indies. Attempts to control and/or eradicate the tick from the Caribbean have largely been unsuccessful because of difficulties relating to the biology of the three-host tick and problems with applying acaricides on a regular basis to free-ranging domestic ruminants. While plastic collars impregnated with insecticides are widely and effectively used in companion animals to control external parasites there is little information on this technology in ruminants. METHODS: Over 21 months we tested the efficacy of slow-release plastic tags impregnated with deltamethrin (7%) and aggregation-attachment pheromones (DPITs) in controlling A. variegatum on free-ranging cattle on two farms on St. Kitts. The tags were replaced every three months or when found to be lost. RESULTS: On sentinel animals fitted with tags containing only aggregation-attachment pheromones there were an average of 23.1 ticks per semi-monthly visit although this number varied considerably, peaking in the dry season around May and being lowest in August to October during the wet season. Significantly fewer ticks (3.5 on average) were found on cattle with DPITs at each visit (P < 0.001). Although the DIPTs provided good control (92% on average), they did not significantly reduce A. variegatum in the environment with tick numbers on sentinels being higher in the second year of the study, despite up to 44% of animals being fitted with DPITs. The tags were economical, costing 0.2% of the 1% flumethrin pour-on treatment widely recommended for A. variegatum control in the Caribbean. The major problem encountered was that 38% of tail tags were lost before they were due for replacement every three months. CONCLUSIONS: Our study has shown that DPITs are cheap to produce, easy to place, only require handling of animals every three months, and are very effective in protecting cattle from A. variegatum. Before DPITs can be considered for eradication programs the problems needing to be addressed include loss of tail tags, particularly in thick vegetation, and the optimum number of animals that must be treated to reduce numbers of ticks in the environment.

Efeito do óleo de capim limão (Cymbopogon flexuosus Stapf) no controle do carrapato dos bovinos / Effect of lemongrass (Cymbopogon flexuosus Stapf) oil on the control of cattle ticks

Esta pesquisa foi conduzida com o objetivo de avaliar o efeito in vitro e in vivo do óleo essencial de capim limão (Cymbopogon flexuosus Stapf) sobre o carrapato dos bovinos [Rhipicephalus (Boophilus) microplus]. Na experimentação in vitro foi utilizado o grupo controle negativo e oito concentrações do óleo de capim-limão (0,5; 1; 2; 5; 10; 20; 50; 100%), em fêmeas ingurgitadas do carrapato. A eficácia de controle foi de 0; 20; 39; 99,5; 100; 100; 100; 100 e 100%, respectivamente. Para a experimentação in vivo foram constituídos três grupos (controle negativo, óleo de capim limão a 2,0% - nível estimado mediante análise de regressão, correspondendo a 95% de eficácia de controle do carrapato da pesquisa in vitro e amitraz a 0,025%), com dezoito vacas da raça Holandesa. Antes (média dos dias -3, -2, -1) e após a aplicação do produto (1, 2, 3, 5, 7, 10, 14 e 21 dias), foram contadas fêmeas ingurgitadas do carrapato. A eficácia de controle foi de 0; 54 e 74,5%, respectivamente, 21dias após o tratamento. Após a aplicação dos tratamentos (controle negativo x tratamento fitoterápico), foram avaliadas as variáveis fisiológicas: frequência cardíaca, respiratória, temperatura do globo ocular e temperatura da pele; os resultados foram similares entre os tratamentos.

This research was aimed at evaluating in vitro and in vivo effects of lemongrass (Cymbopogon flexuosus Stapf) oil on cattle ticks (Rhipicephalus (Boophilus) microplus). Negative control group and eight concentrations of lemongrass oil (0.5; 1; 2; 5; 10; 20; 50; 100%), were used on in vitro trials with engorged female ticks. The efficacy of control ticks was 0; 20; 39; 99.5; 100; 100; 100; 100 and 100%, respectively. For the in vivo trial, eighteen Holstein cows were allocated to three groups (negative control, lemongrass oil at 2.0% - level estimated by regression analysis, accounting for 95% efficacy of control ticks on in vitro trial, and amitraz at 0.025%). Engorged female ticks were counted before (mean of days -3, -2, -1) and after treatment (1, 2, 3, 5, 7, 10, 14 and 21 days). The efficacy of control ticks was 0; 54 and 74.5%, respectively, at 21 days after treatment. Physiologic variables were evaluated after treatments (negative control x phytotherapic treatment). Similar results were found between the treatments for physiological variables.

[Fungal bio-control agents against ixodid tick--a review].

Entomopathogenic fungi as potential agents for bio-control have been widely applied in the control of insect pests in agriculture. However, the application remains in laboratory scale for the control of ectoparasites. Owing to the need to combat the short lasting period of chemical acaricides and reduction of pollution, it is urgent to develop sufficient, stable and safe measures for tick control. We reviewed the primary scientific achievements in utilization of environmental microbes for controlling of ticks. Studies conducted in this field may benefit to sustainable development, environmental protection, maintaining ecological balance and production of green products.

Efeito do extrato aquoso do algodão de seda (Calotropis procera Aiton) sobre a eficiência reprodutiva do carrapato bovino / Effect of aqueous extract of silk cotton (Calotropis procera Ait. R.Br.) on the reproductive performance of Rhipicephalus microplus

O carrapato Rhipicephalus microplus é um dos principais parasitos dos rebanhos bovinos. Diferentes grupos de carrapaticidas sintéticos têm sido empregados para o controle desse ácaro, contudo, o uso constante desses produtos tem selecionado populações resistentes. Na tentativa de minimizar esses impactos tem-se buscado avaliar fitoterápicos para o controle desse parasito. Assim, objetivou-se analisar a eficácia in vitro do extrato aquoso do algodão de seda em diferentes concentrações no controle da postura e eclodibilidade dos ovos do R. microplus. Foram avaliados os efeitos das concentrações 1, 5, 10, 25, 50, 75 e 100% do extrato aquoso obtido juntamente com controles com água destilada ou com cipermetrina, 12,5 mg L-1, associada a organofosforado, 150 mg L-1, sobre a eficiência reprodutiva do carrapato. Foi realizado o biocarrapaticidograma sendo que a eficácia acaricida das concentrações 5, 25 e 100% foram superiores àquela observada para o produto comercial utilizado, que correspondeu a 93,98%, indicando a importância de futuras pesquisas para avaliar o potencial toxigênico e a eficácia in vivo dessa planta para o controle do R. microplus .

The tick Rhipicephalus microplus is one of the main parasites of bovine herds. Different groups of synthetic acaricides have been used to control this mite; however, the constant use of these products has selected resistant populations. In an attempt to minimize these impacts, researchers have tried to evaluate herbal remedies to control this parasite. Therefore, the aim of this study was to analyze the in vitro efficacy of aqueous extract of silk cotton at different concentrations to control the hatchability of R. microplus eggs. The effects of the concentrations 1, 5, 10, 25, 50, 75 and 100% aqueous extract together with controls with distilled water or with cypermethrin, 12.5 mg L-1, associated with organophosphate, 150 mg L-1, were assessed on the reproductive efficiency of the tick. Immersion test was performed and the acaricide efficacy of the 5, 25 and 100% concentrations were higher than that obtained for the commercial product, which corresponded to 93.98%, indicating the importance of further research to assess the toxigenic potential and the in vivo efficacy of this plant to control R. microplus .