Assessing the value and knowledge gains from an online tick identification and tick-borne disease management course for the Southeastern United States.

BACKGROUND: Tick-borne diseases are a growing public health threat in the United States. Despite the prevalence and rising burden of tick-borne diseases, there are major gaps in baseline knowledge and surveillance efforts for tick vectors, even among vector control districts and public health agencies. To address this issue, an online tick training course (OTTC) was developed through the Southeastern Center of Excellence in Vector-Borne Diseases (SECOEVBD) to provide a comprehensive knowledge base on ticks, tick-borne diseases, and their management. METHODS: The OTTC consisted of training modules covering topics including tick biology, tick identification, tick-borne diseases, and public health, personal tick safety, and tick surveillance. The course was largely promoted to vector control specialists and public health employees throughout the Southeastern US. We collected assessment and survey data on participants to gauge learning outcomes, perceptions of the utility of knowledge gained, and barriers and facilitators to applying the knowledge in the field. RESULTS: The OTTC was successful in increasing participants' baseline knowledge across all course subject areas, with the average score on assessment increasing from 62.6% (pre-course) to 86.7% (post-course). More than half of participants (63.6%) indicated that they would definitely use information from the course in their work. Barriers to using information identified in the delayed assessment included lack of opportunities to apply skills (18.5%) and the need for additional specialized training beyond what the OTTC currently offers (18.5%), while the main facilitator (70.4%) for applying knowledge was having opportunities at work, such as an existing tick surveillance program. CONCLUSIONS: Overall, this OTTC demonstrated capacity to improve knowledge in a necessary and underserved public health field, and more than half of participants use or plan to use the information in their work. The geographic reach of this online resource was much larger than simply for the Southeastern region for which it was designed, suggesting a much broader need for this resource. Understanding the utility and penetrance of training programs such as these is important for refining materials and assessing optimal targets for training.

Microbial agents for the control of ticks Rhipicephalus microplus.

Ticks are ectoparasites responsible for the transmission of various pathogens to vertebrates. They represent one of the major threats to livestock production worldwide due to their impact on the health, production and welfare of livestock destined for human consumption. The development of resistance to the main families of ixodicides used for their control has led to the search for new alternatives, where microbial control is an option. The use of microbial control agents against the tick Rhipicephalus microplus is reviewed in this paper. Bacteria such as Bacillus thuringiensis, Serratia marcescens and Staphylococcus spp. the nematodes Steinernema spp. and Heterorhabditis spp. as well as the fungi Metarhizium anisopliae and Beauveria bassiana are the most studied organisms for use as biological control agents against ticks. Laboratory, stable and field trials with free-living and parasitised ticks have shown that microbial agents can control both susceptible and ixodicide-resistant tick populations. However, multidisciplinary studies using novel tools like genomics, transcriptomics and proteomics should be carried out to understand the virulence factors which microbial agents use to induce pathogenesis and virulence in ticks. In addition, applied research will be carried out with the aim of improving techniques for large-scale application, as well as the improvement of cultivation, storage, formulation and application methods.

Strategic control of the cattle tick Rhipicephlaus microplus applied to rotational and silvopastoral grazing systems in subtropical areas.

This work evaluated if strategic control based on no more than three or four annual treatments is useful to control Rhipicephalus microplus infestations on cattle when it is applied to intensive rotational grazing and silvopastoral systems with high stocking rates in subtropical areas. In the intensive rotational grazing system, three annual treatments with chemical acaricides were applied on cattle in two different schemes: between spring and early summer and from late winter and late spring. Strategic control based on three treatments with chemical acaricides from late winter to late spring plus an additional fourth treatment in summer was tested in the silvopastoral system. In the intensive rotational grazing systems, the control schemes allow to reach a significant reduction in the tick load on cattle considering a time interval from spring to autumn. However, the efficacy levels were not high enough in some specific moments, namely, the tick counts of summer and autumn (there were not significant differences between treated and control groups). The scheme evaluated in the silvopastoral grazing system yielded better results than those tested for the intensive rotational system, because significant differences in tick load between treated and control groups were observed in all post-treatment counts and when the analysis was performed for the whole study period. However, values of efficacy in the count-by-count comparison were disparate, ranging from 64.1 to 99.7. Although the efficacy values obtained in the silvopastoral system were better than those of the rotational grazing systems, the total tick load on treated cattle in autumn was not low enough (mean abundance values 25.14 and 38.14). Ticks were more evenly distributed among hosts in late summer and autumn than in spring or early summer, where few hosts carry most of the ticks. Some management strategies as intensive rotational systems or silvopastoral structures can lead to a more efficient forage use, but they imply greater tick challenge than in extensive grazing systems. In these situations, the schemes of strategic control bases on three or four annual treatments should be complemented with additional tactical treatments in late summer or autumn.

Repellent activity of the non-host semiochemical (E)-2-octenal against Amblyomma sculptum and Amblyomma dubitatum ticks under field conditions.

Amblyomma ticks pose a significant public health threat due to their potential to transmit pathogens associated with rickettsial diseases. (E)-2-octenal, a compound found in donkeys (Equus asinus), exhibits strong repellent properties against Amblyomma sculptum nymphs under laboratory conditions. This study assessed the effectiveness of the (E)-2-octenal in wearable slow-release devices for personal human protection against Amblyomma ticks under natural conditions. Slow-release devices treated with (E)-2-octenal and untreated controls were prepared and tested on two volunteers walking through a tick-infested area in Goiania, Brazil. The experiment was conducted twice daily for three series of 10 days, with each volunteer wearing two devices attached to each leg, one on the ankle and one just above the thigh. Volunteers with control and treated devices exchanged them between rounds. Also, the daily release rate of (E)-2-octenal from the slow-release devices was determined in the laboratory, increasing significantly from 0.77 ± 0.14 µg/day on the first day to 9.93 ± 1.92 µg/day on the 4th day and remaining constant until the 16th day. A total of 5409 ticks were collected from both volunteers. Treated devices resulted in recovering fewer ticks (n = 1,666; 31%) compared to untreated devices (control: n = 3,743; 69%). (E)-2-octenal effectively repelled Amblyomma spp. larvae, A. sculptum adults, and exhibited pronounced repellency against A. dubitatum nymphs and adults. These findings suggest the potential of (E)-2-octenal delivered by wearable slow-release devices as a green-based repellent. Further improvements, however, are necessary to provide better protection for humans against A. sculptum and A. dubitatum in field conditions.

What is the optimal timing to initiate strategic control of Rhipicephalus microplus in taurine cattle in a tropical region?

Cattle tick control poses a significant challenge for livestock in tropical and subtropical regions. The objective of this study was to determine the most suitable timing to initiate a strategic tick control program and to identify the ideal number of acaricide treatments for adult taurine cattle (Bos taurus taurus) in a tropical region throughout the year. Three groups with 10 bovines each were performed: T01 (strategic treatment in late autumn/winter/late spring, every 28 days), T02 (strategic treatment to act in the "first tick generation" - early spring/summer/early autumn, every 28 days) and T03 (control). Tick counts (females 4-8 mm) were conducted every 14 days. If the tick burden in any group reached 30 or more during these counts, we applied an additional treatment. Over the course of a year, T02 required significantly fewer (p < 0.05) acaricide treatments than T01, with nine treatments for T02 and eleven for T01. Furthermore, during the tick counts, animals in T02 showed a lower tick burden compared to those in T01. Initiating the strategic tick control program in early spring, corresponding to the first tick generation, proved more effective than starting in autumn. This approach not only required fewer acaricide treatments but also resulted in a reduced tick burden. These benefits are particularly valuable in terms of animal welfare and managing acaricide resistance issues.

Influence of the acaricide emulsion pH on the effectiveness of spray products to control the cattle tick: laboratory and field investigations.

The current work evaluated the efficacy of 10 commercial acaricides in different pHs (4.5, 5.5, and 6.5) in laboratory (adult immersion tests (AIT), pH evaluation over time) and field assays (tick counts and efficacy). In the AIT (n=70), higher efficacies were obtained when the acaricide emulsion had a more acidic pH (4.5), mainly for two combinations of pyrethroids + organophosphate (acaricide 3 and acaricide 9). For amidine, a higher pH (6.5) showed a higher efficacy. Over time, there was a trend in the pH of these emulsions increasing. When the efficacy of chlorpyrifos + cypermethrin + piperonyl butoxide (acaricide 3) at different pHs was evaluated over time (0, 6, 12, and 24h) by AIT, the less acidic pH (6.5) showed a strongly variation in the acaricide efficacy range. The mean pH of the water samples from different regions of Brazil was 6.5. In the field, the association of pyrethroid + organophosphates (acaricide 9) with pH of 4.5 and 5.5 were more effective in tick control than the emulsion prepared with this same spray formulation at pH 6.5. The pH of the acaricide emulsions is an important point of attention and is recommended that the veterinary industry start to develop/share information regarding how the pH can affect the acaricide efficacy.

Morphophysiological analysis of the salivary glands of Rhipicephalus sanguineus sensu lato (Acari: Ixodidae) exposed to ozonated water: A control strategy.

The tick Rhipicephalus sanguineus sensu lato has great medical and veterinary importance, mainly because the ability to transmit many diseases, causing harm to pets but also risks to public health. The blood spoliation and transmission of pathogens occur because of the immunosuppressive action of these ticks' saliva, a potent mixture of bioactive substances that is secreted by the salivary glands, one of the organs responsible for their biological success, and hence the target of studies for their control. Ozone has promise for use as an alternative acaricide, due to its proven efficiency in controlling agricultural and food pests, besides posing no risk of environmental contamination or to animal and human health. Therefore, this study evaluated the acaricidal potential of exposure of females of R. sanguineus s.l. to ozonated water at many concentrations and analysed the morphophysiological alterations of the salivary glands, employing histological and light microscopic techniques. The results demonstrated that the ozonated water at the concentrations investigated caused severe alterations in the salivary glands, bringing a new perspective for control of R. sanguineus s.l., through an ecologically correct method due to the absence of harm to non-target organisms and the environment.

Evaluation of Barricade® to enhance survival of entomopathogenic nematodes on cowhide.

Entomopathogenic nematodes (EPNs), Steinernema riobrave and Heterorhabditis floridensis are under evaluation for eradication of the southern cattle fever tick, Rhipicephalus microplus infesting nilgai antelope, in South Texas. Cattle fever ticks are a significant threat to the U.S. livestock industry. Although they have been eradicated in the U.S. they frequently re-invade along the Texas-Mexico border. Remotely operated field sprayers have been developed to directly treat nilgai antelope with EPNs as they transit fence crossings and as they contact wetted foliage and soil from the surrounding area. EPNs are known to be susceptible to mortality from ultraviolet light (UV) and desiccation. A sprayable fire gel, Barricade®, has been reported to protect EPNs from UV and desiccation but has not been tested on animal hides. Barricade® at 1 and 2 percent rates was mixed with the water solution of S. riobrave and H. floridensis and applied to cowhides (to mimic direct treatment of nilgai) and filter paper and then these substrates were placed out of doors in 0, 30, 60 or 120 min of sunlight. Wax moth larvae, Galleria mellonella, were exposed to the cowhides and filter paper to determine efficacy of the EPNs. Efficacy of S. riobrave with 1 and 2% Barricade® gel applied to cowhides was significantly improved at 30 and 60 min as compared to the control. At 120 min mortality of the wax moth larvae was near zero for both the control and the treatments. Similar results were found with the filter paper test. In contrast, efficacy of H. floridensis with Barricade® applied to cowhides or filter paper was not significantly improved at 30, 60 or 120 min as compared to the water only control. Barricade® has the potential to improve the efficacy of S. riobrave and other EPNs by reducing mortality and desiccation, especially when used in the remotely operated sprayer developed for treatment of cattle fever tick infested nilgai.

Integrated control of the cattle tick, Rhipicephalus australis (Acari: Ixodidae), in New Caledonia through the Pasture and Cattle Management method.

Development of the Pasture and Cattle Management (PCM) method is a priority to control the cattle tick, Rhipicephalus australis, in New Caledonia. The PCM method provides the foundation for sustainable integrated tick control because approximately 95% of cattle ticks in infested pastures are off the host in the non-parasitic life stages, and the practice of treating cattle intensely with chemical acaricides is a risk for the emergence of resistance to these active ingredients in commercial acaricidal products available for veterinary use. Here, we report the findings of an assessment survey to document the utility of the PCM method. Analyses of questionnaire data provided by 21 beef cattle producers describing their management of 37 herds informed how to (1) assess the ability of PCM to reduce acaricide use and (2) prioritize best practices and define recommendations to breeders promoting efficient tick control with minimum acaricide use. Boosted regression tree analysis showed a significant (p = 0.002) reduction of ≈33% in the number of acaricide treatments from 7.9 to 5.3 per year by using PCM. Of the 24 factors identified as potentially affecting acaricide use, six factors accounted for ≈86% of the variability in number of acaricide treatments applied annually. The six most influential factors involved farm characteristics as well as pasture and herd management recommendations. These results demonstrated the usefulness of PCM for integrated control of R. australis infestations while reducing acaricide use to improve cattle production in New Caledonia.

Low-temperature storage of the poultry red mite, Dermanyssus gallinae, facilitates laboratory colony maintenance and population growth.

The poultry red mite, Dermanyssus gallinae, is currently the most common ectoparasite affecting egg-laying hens. Since continuous culture of D. gallinae on birds is a biologically and economically costly endeavour, storage techniques for mites are urgently needed. Effects of temperature on adult and nymph survival were first studied to optimize storage conditions. Then, fecundity of D. gallinae was studied after mites were stored at optimal storage conditions. Results showed the survival rates of protonymphs (42.11%), deutonymphs (8.19%) and females (19.78%) at 5°C after 84 days were higher than those at 0, 25 and 30°C. Thereafter the fecundity and the capability of re-establishing colonies of D. gallinae were evaluated after they were stored for 40 and 80 days at 5°C. After storage, the mean number of eggs showed no statistical difference between treated (5°C for 40 or 80 days) and control groups (25°C for 7 days), while the hatching rates of eggs were in all cases above 97%. The dynamic changes of mite populations and egg numbers showed similar trends to the control group after the stored adult or nymph mites were fed on chicks. Dermanyssus gallinae can be successfully stored at 5°C for 80 days with no interference with the fecundity of mites, and the stored mites could re-establish colonies successfully. Adults and nymphs were two main stages with capability for low temperature storage. These results suggest that low temperature storage is a viable option for colony maintenance of D. gallinae under laboratory conditions.

Management strategies to minimize the use of synthetic chemical acaricides in the control of the cattle tick Rhipicephalus (Boophilus) microplus (Canestrini, 1888) in an area highly favourable for its development in Argentina.

The aim of this work was to test the efficacy of winter-spring control strategies against Rhipicephalus (Boophilus) microplus (Canestrini, 1888) (Ixodida: Ixodidae) in an area highly favourable for its development in Argentina. Control schemes using three or four annual applications of synthetic acaricides were evaluated. Furthermore, the dynamics of the non-parasitic phases of R. microplus were analysed to provide a framework for the application of pasture spelling as a tool for tick control. The treatment schemes provided appropriate levels of efficacy against R. microplus and also prevented the occurrence of the major peak in abundance of this tick in autumn. A significant overall effect against R. microplus can be achieved when the control strategies tested in this study are applied within the area most ecologically favourable for this tick in Argentina. Analysis of the dynamics of the non-parasitic phase of R. microplus indicates that the spelling period required to achieve a significant reduction of larvae in pastures fluctuates between 12 and 17 weeks if spelling is initiated in spring or early summer, but between 20 and 28 weeks if spelling is started in late summer, autumn or winter.

Metarhizium anisopliae sensu lato (s.l.) oil-in-water emulsions drastically reduced Rhipicephalus microplus larvae outbreak population on artificially infested grass.

Rhipicephalus microplus Canestrini, 1887 (Arachnida: Ixodidae) is a mandatory bloodsucking ectoparasite, and it is considered one of the main sanitary problems in livestock. In the development of new technologies for controlling ticks, Metarhizium anisopliae complex (M. anisopliae s. l.) Sorokin, 1883 (Ascomycota: Clavicipitaceae) have been shown to be an effective and safe alternative. However, when applied in the field, abiotic factors may directly influence their microbial activity, and different oily adjuvants enhance fungal efficacy, stability and viability under environmental conditions. Here, the efficacy of two Metarhizium anisopliae s.l. isolates (CG 148 and CG 347) were compared in mineral oil (MO) or vegetable oil (VO) emulsions to control cattle ticks under semi-natural conditions, as well as their persistence in the soil over time. Engorged female ticks were placed on the soil of grass pots previously treated or not with conidial oil-in-water emulsions. Both M. anisopliae s.l. oil-in-water emulsions tested were able to control R. microplus, achieving up to 100% daily efficacy, and remained viable in the soil for up to 60 days after treatment. These results show the prospective applicability of Metarhizium spp. to control the cattle tick and a real possibility for its control in the environment.

Ultrasound-assisted extraction extracts from Stemona japonica (Blume) Miq. and Cnidium monnieri (L.) Cuss. could be used as potential Rhipicephalus sanguineus control agents.

Nicotiana tabacum, Stemona japonica, and Cnidium monnieri are common plants that are widely used for their anti-parasitic properties. The purpose of this study was to evaluate the acaricidal activity of extracts from these plants against the brown dog tick, Rhipicephalus sanguineus. A composition analysis of crude extracts by GC-MS was conducted to discover compounds with acaricidal effects. The toxicity of extraction against the engorged nymphs of R. sanguineus was evaluated by an immersion test. The results showed that the crude extracts of S. japonica and C. monnieri in varying ratios, concentrations, and from different extraction methods, had a killing effect on R. sanguineus. Lethality reached 76.67% ± 0.04410 when using a 1:1 extract of S. japonica:C. monnieri in 75% ethanol with ultrasonic extraction; the crude extract was determined at a concentration of 0.5 g/mL. GC-MS results showed that osthole and 5-hydroxymethylfurfural (5-HMF) are the main components of the extract. These results suggested that ultrasound-assisted extraction (UAE) extracts contained acaricidal components acting against R. sanguineus, which may result in the development of effective extracts of S. japonica and C. monnieri as a source of low-toxicity, plant-based, natural acaricidal drugs.

Repellency effect of Pilocarpus spicatus A. St.-Hil essential oil and nanoemulsion against Rhipicephalus microplus larvae.

Rhipicephalus microplus, the cattle tick, is a major cause of economic losses in bovine production. Due to the widespread acaricidal resistance to commercially available products, as well as their toxicity and environmental impact, alternative control methods are required. Nanoformulations produced from plant extracts as bioactive substances are very promising as innovative acaricidal agents. Thus, the aim of this study was to evaluate the in vitro repellent activity of Pilocarpus spicatus essential oil and its nanoemulsion against R. microplus, using larval repellent test (RT). The essential oil was extracted by hydrodistillation, using a Clevenger-type apparatus. The nanoemulsion was prepared with 5% essential oil, 5% tween 80, and 90% water, using the phase inversion method (50 mg/mL). Limonene was the major component (46.8%) of the essential oil, as determined by gas chromatography-mass spectrometry (GC/MS) and confirmed by flame ionization detection (GC/FID). According to the RT results, the essential oil had a repellent activity greater than 69%, from concentrations of 3.12 mg/mL (69.81 ± 10%) to 50 mg/mL (98.10 ± 0.6%), whereas the nanoemulsion at 50 mg/mL presented repellent activities of 97.14 ± 1.37% and 97.89 ± 0.52% 6 and 10 h after treatment, respectively. These values regarding to total repellency were very close to those calculated for mortality corrected by Abbott's formula. The phase inversion method preserved the chemical and physical characteristics of the essential oil since both reached an equal repellent effect at the same concentration. Therefore, P. spicatus essential oil and nanoemulsion had excellent repellent activities against R. microplus larvae, demonstrating its potential for future use as an alternative for tick control.

Effectiveness of control strategies for Varroa jacobsoni and Tropilaelaps mercedesae in Papua New Guinea.

Apiculture in the Pacific island country of Papua New Guinea (PNG) is under significant pressure from emerging parasitic mites, Varroa jacobsoni and Tropilaelaps mercedesae. Although numerous mite control products exist, beekeepers in PNG have limited resources and access to these products and their effectiveness under local conditions is untested. Here we determined the effectiveness of two brood manipulation strategies-queen caging and queen removal-for managing V. jacobsoni and T. mercedesae in comparison to the chemical miticide Bayvarol®. Our results found Bayvarol was the most effective control strategy for V. jacobsoni, maintaining high efficacy (> 90%) over 4 months with significantly reduced levels of V. jacobsoni compared to untreated control hives. In contrast, T. mercedesae were significantly reduced by the brood manipulation strategies over 2 months, but not significantly by Bayvarol compared to the controls. These results highlight that a combination of strategies is likely needed to effectively manage both mite pests in PNG. We discuss how these findings are relevant to informing best practice for honey bee biosecurity and how these strategies can be implemented to improve the effectiveness of mite management for PNG beekeepers.

Development of essential oil-based phyto-formulations to control the cattle tick Rhipicephalus microplus using a mixture design approach.

The cattle tick Rhipicephalus (Boophilus) microplus is one of the most important ectoparasites for livestock in tropical and subtropical areas around the world. This tick economically impacts cattle production by reducing weight gain and milk production. Moreover, it is a vector of pathogens causing diseases such as babesiosis and anaplasmosis. Conventional tick control relies mainly on the use of chemical acaricides; however, their intensive use has led to the rapid appearance of resistant tick populations. It is therefore necessary to look for alternative tick control products. In that sense, plant extracts might represent a promising source of new acaricides. Previously, we reported a significant acaricide effect of essential oils from selected plant species. In the present study, we used a mixture design approach to develop phyto-formulations by combining individual essential oils. We produced several mixtures at 10% containing different proportions of individual essential oils (ranging from 0 to 1) from cinnamon (Cinnamomum zeylanicum), cumin (Cuminum cyminum) and allspice (Pimenta dioica) and tested their acaricidal activity against R. microplus ticks by means of larval packet test (LPT) and adult immersion test (AIT) assays. The optimal mixture predicted against R. microplus was composed of 66%, 17% and 17% of essential oils from C. zeylanicum, C. cyminum and P. dioica, respectively. We generated an estimated response surface contour plot that estimates 80%-100% acaricidal efficacy. In the optimal mixture 34 compounds were identified, which represent 98.65% of the total composition, with cinnamaldehyde (37.77%), ß-caryophyllene (13.92%), methyl eugenol (12.27%) and cuminaldehyde (8.99%) being the major components. Next, we developed emulsions by combining the optimal mixture with several surfactants and determined particle size, Zeta potential, stability and bioactivity. Emulsions containing 2% and 5% Tween 20 or Tween 80 remain stable after 14 days at 54 °C. Finally, optimized emulsion retained a high acaricidal activity against larval and adult R. microplus ticks. Taken together, our findings showed the usefulness of mixture design method for the development of essential oil mixtures with potent acaricidal activity. These formulations have the potential to successfully control tick infestations.

Molecular, histological and ultrastructural characterization of cytotoxic effects of amitraz on the ovaries of engorged females of Rhipicephalus (Boophilus) annulatus.

In the present study, the cytotoxic effects of amitraz, an octopamine receptor agonist on the reproductive system of engorged adult females of Rhipicephalus (Boophilus) annulatus were assessed using histology, electron microscopy and octopamine beta (OCTß) receptor transcriptional expression analysis. Adult immersion test (AIT) was performed by immersing the fully engorged female ticks for 2 min in different concentrations of amitraz (200, 250, 300, 350 ppm). Amitraz at the dose of 300 ppm, caused an adult tick mortality of 16.66 ±â€¯6.80 per cent, inhibition of fecundity of 75.80 per cent and hatching of 50 per cent of ova laid by treated ticks. Histological changes in the ovaries of ticks collected after 24 h of treatment with amitraz (300 ppm), in comparison with controls (distilled water/methanol) were identified by microscopical examination of sections (4  µm) stained using haematoxylin and eosin. These changes included reduction in size and basophilia of stage I oocytes, presence of cytoplasmic vacuoles of various sizes around germinal vesicle of stage II oocytes, wavy basement membrane of stage III oocytes and reduction in size and number of mature stage IV and V oocytes. Electron microscopy was employed for understanding the structural changes in the ultrathin sections (60 nm) of ovaries. Ticks treated with amitraz showed major ultrastructural changes such as irregular nuclear membrane, crystolysis of mitochondria and detachment of external and internal layers of basal lamina of oocytes. The cDNA synthesized from the total RNA of whole ticks and ovaries of ticks treated with amitraz along with controls were used for relative quantification of Octopamine ß receptor (OCTß-R) expression based on the 2-ΔΔCT method by quantitative real time PCR (qRT PCR). Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was used as endogenous control. Down regulation of expression of OCTß-R mRNA in the ovaries of amitraz treated ticks was observed compared to controls. Thus, the inhibition of fecundity observed in the ticks treated with amitraz can be attributed to the major structural changes and decreased expression of OCT ß receptor mRNA induced by it in the ovary.

Use of Metarhizum aniopliae s.l. to control soil-dwelling longhorned tick, Haemaphysalis longicornis.

The longhorned tick (bush tick),Haemaphysalis longicornis (Ixodida: Ixodidae), is a serious pest; it transmits the severe fever with thrombocytopenia syndrome (SFTS) virus to humans and has a wide distribution. The use of chemical control is not favored for environmental and health reasons, so more environmentally sound management methods need to be developed. Herein, we describe the use of an entomopathogenic fungal library to develop a fungus-mediated tick management system. Field-collected nymphs were assayed for their susceptibility to entomopathogenic fungi belonging to genera Beauveria, Metarhizium, Cordyceps, and Akanthomyces. Three M. anisopliae s.l. isolates, JEF-214, -279, and -290 showed high virulence in a dose-dependent manner. One Cordyceps isolate was pathogenic but virulence was much lower than the M. anisopliae isolates. Beauveria isolates were not pathogenic to the tick. Because the longhorned tick dwells on the soil surface except for blood-feeding periods, the soil surface was sprayed with conidial suspensions of the isolates after the release of longhorned ticks. The treatments resulted in 60-90% mortality after 30 days. M. anisopliae s.l. isolates were highly virulent against longhorned tick, and the application of fungus-based biopesticides on the soil surface could be an effective control strategy to reduce the tick population for long-term tick management.

Aerial application methods control spider mites on corn in Kansas, USA.

The Banks grass mite, Oligonychus pratensis (Banks), and two-spotted spider mite, Tetranychus urticae Koch, are important chelicerae herbivores on irrigated corn in Kansas, USA. They cause loss of foliage, stalk breakage, kernel shrinkage and yield loss. Aerial application methods were evaluated to control spider mites in a commercial corn field in August, 2017, near Hoxie, Kansas. Dimethoate (0.56 kg active ingredient/ha) and Lorsban Advanced (1.05 kg active ingredient/ha) mixed with a nonionic surfactant, Traverse (0.25% v/v), were aerially applied using conventional flat-fan hydraulic nozzles at 28.1 L/ha and aerial electrostatic nozzles at 9.3 L/ha. To assess spray droplet spectra of the aerial application methods, water sensitive paper samplers were deployed at the whorl of husk leaves at the tip of the ear before aerial spray treatments were applied. Spray droplet spectra were quantified using commercial image analysis software. Treatment efficacy was assessed both objectively and subjectively. Objective efficacy evaluation incorporated the use of an active multispectral optical sensor via spectral analysis of the midrib regions of corn leaves on the abaxial surface where spider mites reside. Subjective damage ratings based upon in-field spider mite movement observations were scored by professional crop scouting consultants. Results of objective spectral analysis and subjective damage ratings indicated that both the conventional and electrostatic nozzles with 283 and 210-µm spray droplet 'volume median diameter' (VMD) at 28.1 and 9.3 L/ha, respectively, controlled spider mites compared to an untreated check.

Thus far but no further: predatory mites do not migrate effectively into strawberry plantations.

Enhancing the performance of predatory mites is often regarded as the best biological control approach towards the spider mite Tetranychus urticae, the main pest of strawberry plantations. Optimizing the colonization of plantations by predators from adjacent areas such as field margins is seen as an important component of conservation biocontrol. We have investigated the factors contributing to enhancing the numbers of predatory mites (Acari: Phytoseidae), such as management of the field margins, vegetation composition and the effect of the presence of woody species. We also tested the penetration of the phytoseiids from the field margins into the crop. In a study carried out in 14 open-field extensively managed strawberry plantations in Poland we found phytoseiids to be abundant in field margins; 14 taxa were discovered. However, only two species Amblyseius andersoni and Euseius finlandicus dispersed a modest distance into the crop. We found that the diversity and densities of the predatory mites were enhanced somewhat by the management type of the field margins; especially the spontaneous vegetation favoured the presence of phytoseiids. However, despite the predatory mites being rather retained in the field margins also significant reduction in numbers of their prey T. urticae was recorded over the course of the year. The low penetration of predatory mites into the main part of the field, indicates that conservation biological control measures in the field margin might not be sufficient on their own to enhance the impact of predatory mites within the main part of the fields.