Acaricidal Efficacy Research Articles

DURATION OF ACARICIDAL ACTION OF THE DRUG «KENEM» AND ECONOMIC JUSTIFICATION FOR THE PROTECTION OF CATTLE FROM IXODIC MITES

The scientific article presents the duration of acaricidal effect of «Kenem» drug, and its economic feasibility for protecting cattle against ixodic ticks. As a result of the study, the acaricidal efficacy and the duration of the residual acaricidal effect of drugs are important components in the planning of anti-tick measures. From a practical point of view, the economic feasibility of treating cattle against ixodic ticks in the presented conditions of acaricides in the southern regions is considered important. Despite the fact that the cost of the drug per 100 head exceeds the cost of a similar drug by 1 788.15 tenge, the frequency of its use is less, and additional installations are not required. This is due to the long duration of residual acaricidal effect of Kenem, which is 30 days, which allows to reduce the number of therapeutic measures.When calculating the economic feasibility for the use of acaricides to protect cattle against ixodic ticks, the most convenient way to prevent the sucking of ixodic ticks to animals is the local application of Kenem, which does not require special equipment and special skills of technical staff. Drug duration is 30 days, therefore the cost of its use for the entire season of active ticks per 1 animal is 44% cheaper, compared to veteran, i.e. 1,421.4 tenge.

Residual Activity of Acaricides for Controlling Spider Mites in Watermelon and Their Impacts on Resident Predatory Mites.

Twospotted spider mite, Tetranychus urticae Koch (Trombidiformes: Tetranychidae), is an important, worldwide pest of watermelon, Citrullus lanatus L. (Thunb.) Matsum. & Nakai (Cucurbitales: Cucurbitaceae). Feeding results in chlorotic spots and leaf necrosis, which can substantially reduce yields. In watermelon, T. urticae is managed solely with acaricides. Issues with acaricide resistance and pesticide label restrictions on number of applications per season require research-based recommendations on products with effective, long-lasting residues. To improve recommendations for T. urticae management in watermelon and to measure possible effects on non-target beneficial mites, we conducted acaricide efficacy trials in two locations in South Carolina, United States. The adulticidal products abamectin, bifenazate, fenpyroximate, and tolfenpyrad and the ovicidal products spiromesifen and etoxazole were tested. We also conducted two bioassays to better determine duration of acaricide residues. In the field trials, all acaricides except tolfenpyrad reduced T. urticae abundance, but all acaricides also reduced abundance of the most common predatory mite, Neoseiulus fallacis (Garman) (Mesostigmata: Phytoseiidae). In the bioassays, abamectin and bifenazate residues caused high adult T. urticae mortality at up to 21 d after treatment, performing better than fenpyroximate and tolfenpyrad. Etoxazole and spiromesifen were longer lasting, with <1 offspring per treated female in the etoxazole treatment at 28 d after treatment. Based on efficacy, abamectin or bifenazate should be rotated with etoxazole for fast knockdown of active stages while reducing reproduction, respectively. However, development and registration of more selective acaricides in watermelon is needed to preserve biological control of T. urticae by predatory mites.

An update on amitraz efficacy against Rhipicephalus microplus after 15 years of disuse.

Amitraz is an acaricide that is widely used in veterinary medicine to control the cattle tick Rhipicephalus microplus. However, controversy exists in the literature regarding the resistance of R. microplus to this product. The present work provides an update on the acaricidal efficacy of amitraz (Triatox®, 12.5 % amitraz) after 15 years without its use on a property. Two in vivo (bovines treated with amitraz and submitted to tick counts, n = 20 animals) and one in vitro (adult immersion test, n = 40 ticks) assays were performed to determine product efficacy. The efficacy of the commercial formulation tested in the first in vivo trial ranged from 14.1 to 47.0%, and in the second from 3.6 to 35.1%, for the 28 days of the experiments. Efficacy for the in vitro trial was 47.38%. The dose recommended by the manufacturer of the product did not cause mortality to most of the ticks of this strain, and efficacy/resistance was not reverted or modified after 15 years (estimated 60 tick generations).

Comparative Efficacy of Synthetic Acaricides Against Tick Infestations in Goats

Comparative Efficacy of Synthetic Acaricides Against Tick Infestations in Goats

Mogućnost primene bifenazata i piridabena u suzbijanju šljivine rđaste grinje (Aculus fockeui) na višnji

In the field trial conducted in 2020 at the locality of Mačvanski Metković (municipality of Bogatić, Serbia), the efficacy of products based on bifenazate and pyridaben in the control of the plum rust mite (Aculus fockeui) on sour cherry was examined. Product Acramite 480 SC (bifenazate) was tested in two application rates, 0.375 l/ha and 0.75 l/ha, while Sanmite 20 WP (pyridaben) was applied in an amount of 500 g/ha. The experiment was performed according to the standard, partially adapted EPPO method for testing the efficacy of acaricides in the control of spider mites in fruit orchards. Based on trial results, it can be concluded that the efficacy of bifenazate was different depending on the application rate of the product. The efficacy of this compound applied in the amount of 0.75 l/ha of the product Acramite 480 SC was very high and ranged between 94.85% and 98.96%, respectively. The same product in the amount of 0.375 l/ha showed low efficacy, which ranged from 55.27% to 88.22%, respectively. The efficacy of pyridaben was high in all evaluations (90.43% - 95.25%).

Acaricidal activity of different fractions of Spilanthes acmella against Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) in Middle gangetic region and toxic compound identified by GCMS-MS

The acaricidal efficacy of fractions (hexane, ethyl acetate & chloroform) of crude methanolic extract of Spilanthes acmella (aerial part) was studied on adult connected to the cattle tick Rhipicephalus (Boophilus) microplus using the Adult Immersion Test (AIT). Crude methanolic extract fractions of (aerial part) Spilanthes acmella showed 100% mortality on every stage at 24 h and 15 days of exposure period of different fractions and concentrations respectively. Mortality % of fractions calculated by LC50 and LC90 values in mg/ml units against Rhipicephalus microplus. Chloroform fraction brings about bioefficacy against tick. GCMS-MS demonstrated that the chemical compression of the active compound was mainly found of Spilanthol (C14 H23 NO, 221.34 g/ mol), N-Isobutyle-2(E), 6(Z), 8E Decatrienamide, accountable for the acaricidal activity of Spilanthes acmella.

Synthesis of Nanocomposites Layered Double Hydroxide via Ocimum basilicum and Its Acaricidal Efficacy Against Multi-Resistance Rhipicephalus annulatus Tick.

A layered double hydroxide (LDH) incorporated with Ocimum basilicum essential oil (OB) was prepared and its acaricide efficacy against Rhipicephalus annulatus tick was investigated. The OB essential oil was extracted from plants farmed in the study area. Zn-Al LDH/Gallate was prepared by co-precipitation method then OB oil was added to obtain OB/LDH nano-composite. The obtained product was characterized by X-Ray Diffraction (XRD), Fourier-transform infrared (FT-IR) and scanning electron microscopy (SEM). The acaricidal activity of different concentrations of the obtained OB/LDH nanocomposite (6.25, 12.5, 25, 50, 100, 200 and 300 l/mL) was evaluated via the adult immersion test (AIT), egg hatchability test (EHT), larval packet test (LPT) and repellency test. OB oil and OB/LDH nano-composite showed 100% adult mortality and prevent egg deposition at a dose of 300 l/mL. Also, eggs hatching was fully inhibited at 300 l/mL while at the concentration of 200 l/mL the inhibition rate was 95%. In LPT, OB/LDH showed a high toxicological effect which leading to 100% and 43% larval mortality at doses of 200 μ l/mL and 100 μl/mL, respectively. Meanwhile OB alone showed 100% and 45% larval mortality at doses of 300 μl/mL and 200 μl/mL, respectively. The LC50, LC90 and LC99 values of OB/LDH and OB were found to be 107.46 versus 209.908 μl/mL, 171.22 versus 282.63 μl/mL and 196.15 versus 298.26 μl/mL, respectively. The repellence activity was lasted for 3 h after application against larvae. OB/LDH was found to be more repellent than OB as evidenced by the RC50 values after 2 h and 3 h (48.82 vs. 79.99 μl/mL and 89.47 vs. 185.32μ l/mL, respectively). Overall, our results proved that LDH enhanced the larvaicidal and repellent efficacy of OB against R. annulatus tick larvae.

In vitro Analysis of the Efficacy of Selected Commercial Acaricides on The Cattle Tick Rhipicephalus (Boophilus) annulatus (Acari: Ixodidae)

Ticks are important to the Nigerian livestock industry because of their ability to cause huge economic loss directly or indirectly. Chemical acaricides have played important roles in control of tick infestation for many years but development of acaricide resistance as being reported worldwide is a huge problem facing the livestock industry and the veterinarians. Thus, this study evaluated the efficacy of available commercial acaricides on Rhipicephalus (Boophilus) annulatus. Using Adult Immersion Test (AIT): the LC50, inhibition of oviposition, control and resistance rates, gradation of tarsal reflexes were determined for ticks treated with different acaricides at five different concentrations the discriminating dose (DD) (the manufacturer’s recommended dose) and four other different concentrations of two below and two above the DD with the aid of prohibit regression. The association between weight and number of eggs laid was analyzed by linear correlation. Macrocyclic lactone(66.7%), Phenylpyrazole (62.5%), Cypermethrin (62.5%), Formamidine(33.3%) and Phenylpyrazole(13% egg production), Macrocyclic lactone (18% egg production), Cypermethrin(20% egg production), Formamidine(49% egg production) have the highest to lowest percentage control and oviposition inhibition values respectively. The LC50 of (Formamidine), (Phenylpyrazole), (Synthetic pyrethroids), (Macrocyclic lactone) against adult R. (B.) annulatus were 100, 8000, 2300 and 6000ppm respectively.The demonstration of acaricide resistancedevelopmentas demonstrated by the ticks in laying of eggs after dipping in acaricideis a call to the need for discovery and use of alternative tick control methods with good therapeutic dose and the need for continuous evaluation of available acaricide.

Epidemiology and control of mange in sheep and goat in menoufia governorate

The present study aimed to investigate the epidemiology of mange disease in Menofia governorate and to identify the efficacy of different acaricides to control mange mites infesting sheep and goat in the governorate. For this purpose, a total number of 1500 sheep and 750 goats were examined during the different months and seasons of the year by visual inspection of animals’ body. The examined animals were also parasitologically and microscopically examined. All parasitological positive samples were subjected to different treatment protocols with acaricides. The results revealed that prevalence of mange in sheep was 24.5% and 23.33% in goat and the highest prevalence of mange in sheep and goat was in summer season, (36.57%) in sheep and (32%) in goat, while the lowest prevalence was in winter, (14%) in sheep and (14.8%) in goat. Moreover, the highest prevalence of mange was observed in Shebein El-Kom , (6.73% , 5.73% ), in sheep and goat, respectively, while the lowest prevalence was noticed in El-Bagour (4% , 3.73%), in sheep and goat, respectively. On the other hand, the results revealed that the efficacy of deltamethrine was 63.55%, the diazinon efficacy was 81.2%, the ivermectin efficacy was 81.95%, On the other hand, the treatment protocol of infested animals with deltamethrine + ivermectin proved an efficacy of 87.63% and the efficacy of the treatment protocol with diazinon + ivermectin was 94.7%.

THE COMPARATIVE EFFICACY OF CERTAIN CHEMICAL AND BOTANICAL ACARICIDESAGAINST TETRANYCHUS URTICAE ON ASHWAGANDHA

Comparative efficacy of certain chemical and botanical acaricides against the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) major pests occurred on Ashwagandha was studied at B.B.D. Govt. P.G. College, Chimanpura, Jaipur during cropping year 2012-2013 and 2013-2014. Eight pesticides were evaluated against T. urticae infesting ashwagandha, out of which Fenazagnite (.05%) was found to be the most effective in the present study where Propargite (.05%) was recorded to be at par in effectiveness with Fenazagnite and NSKE was found to be most effective among the plant extracts and was at par with the treatment of Azadirachtin.

Mode of application of acaricides against the ectoparasitic mite (Varroa destructor) infesting honeybee colonies, determines their efficiencies and residues in honey and beeswax

Objectives: Ensuring adequate treatments for acaricide efficacy to combat mite infestation is a pre-requisite for healthy honeybees and a good yield of hive products. Therefore, this study aimed to assess the effect of the mode of application on efficiency of two acaricides; Vapcozin-20 (amitraz) and Mavrik 2F (fluvalinate) against Varroa mite infesting brood and adult honeybees. Methods: To do so, we used 21 honeybee colonies (3 colony per treatment) between December 2018 and March 2019. Varroacides were applied by three different methods: cotton strips (impregnated in each tested acaricide solution for 24 h) or direct spraying (5 mL for each colony) or using carton paper (impregnated in each tested acaricide solution for 5 min) then put directly on the top of brood combs. All treatments were applied twice at a month interval. We also quantified acaricides residues in honey and beeswax after 1, 15, 30, 60 and 90 days of acaricides treatment. Results: The different application methods of both acaricides against V. destructor showed relatively similar efficiencies in both brood and adult honeybees that ranged from 93.8 to 100% for Mavrik 2F and from 83.75 to 96.37% for Vapcozin with no significant differences between different application methods. Fluvalinate residues detected in both honey and wax collected from colonies treated with the strips method, exceeded the maximum residue limits (0.05 ppm for both honey and wax) according to EU Pesticides database. While amitraz residues were not detected in any colonies treated with Vapcozin-20 after 3 months of treatment, regardless of the application method. Conclusions: The three different methods of application of Mavrik 2F and Vapcozin-20 showed great efficiency for the control of Varroa mite, however the application of both miticides using carton paper method was the most appropriate because it showed very minimal acaricides residues.

USE OF FLUMETHRIN-IMPREGNATED COLLARS TO MANAGE AN EPIDEMIC OF SARCOPTIC MANGE IN AN URBAN POPULATION OF ENDANGERED SAN JOAQUIN KIT FOXES (VULPES MACROTIS MUTICA )

Sarcoptic mange epidemics can have long-lasting impacts on susceptible wildlife populations, potentially contributing to local population declines and extirpation. Since 2013, there have been 460 reported cases of sarcoptic mange in an urban population of endangered San Joaquin kit foxes (Vulpes macrotis mutica) in Bakersfield, CA, with many of them resulting in fatality. As part of a multifaceted response to mitigate mange-caused mortalities and reduce this conservation threat, a 2-yr randomized field trial was conducted to assess the efficacy of long-acting flumethrin collars against sarcoptic mange in kit foxes. Thirty-five kit foxes living in a high-density population on a college campus were captured, examined, administered selamectin, and each fox randomly assigned to either receive a flumethrin collar placed within a VHF radio collar or a VHF radio collar without flumethrin. The survival and mange-infestation status of study animals was monitored via radio telemetry, remote cameras, and periodic recapture examinations and compared among treated and control kit foxes using a Cox proportional hazards model. The average time to onset of mange for treated kit foxes (176 days) was similar to controls (171 days) and treatment with flumethrin did not significantly reduce mange risk for all kit foxes. Kit foxes that had a mild mange infestation at the beginning of the study were four times more likely to develop mange again, regardless of flumethrin treatment, compared with kit foxes that had no signs at initial recruitment. This study demonstrates an approach to evaluating population-level protection and contributes to the limited literature on efficacy, safety, and practicality of acaricides in free-ranging wildlife.

A life stage-targeted acaricide application approach for the control of Haemaphysalis longicornis

Haemaphysalis longicornis Neumann is an invasive tick species that has recently been detected in the eastern United States. We designed field studies to monitor the population dynamics of H. longicornis over a year (2019) in New Jersey, and to assess the efficacy of a pyrethroid acaricide (lambda-cyhalothrin) in controlling this tick using a stage-treatment approach. Nymphs were the most abundant life stage found host-seeking from May through early July, followed by a brief period of high adult activity in mid-July, and a very high larval peak extending from late July through October. Overall, 542 adults, 1910 nymphs, and 69,238 larvae were recorded during the sampling. In the present study, the efficacy of acaricide treatments to suppress host-seeking ticks was assessed by applying lambda-cyhalothrin once during each of the three periods of activity for nymphs (June), adults (July), and larvae (August), or sequentially during all three months. Control plots were left untreated and used for phenology studies. Applications in June and July provided 100 % control of all life stages, including the dominant nymphal and adult stages for 42 and 35 d, respectively. Ticks re-established at normal or reduced levels following applications in June or July, respectively, compared to untreated controls. The application in August provided 100 % control for 49 d, and a high level of suppression (>99 % control) remained through the end of the tick season in October. This study therefore supports that single pyrethroid applications can provide 100 % control of H. longicornis for up to 7 wk, and a single late-summer application towards the end of host-seeking adult activity can provide near complete control of the larval population. An evaluation of single applications over the course of the season revealed that treatments in July or August did not lead to significant reductions in the nymphal population. However, multiple sequential treatments targeting all life stages provided 66 %, 97 %, and >99 % control of adults, nymphs, and larvae, respectively through the season of H. longicornis activity.

Evaluation of Dry and Wet Formulations of Oxalic Acid, Thymol, and Oregano Oil for Varroa Mite (Acari: Varroidae) Control in Honey Bee (Hymenoptera: Apidae) Colonies

The efficacy and safety of dry and wet formulations of three nonsynthetic compounds, oxalic acid (OA), thymol (T), and oregano oil (OO), for the control of Varroa destructor Anderson and Trueman infestations in honey bee (Apis mellifera Linnaeus) colonies were determined. The treatments were OA in dust, OA diluted in glycerin solvent embedded in a towel, T in dust, T in glycerin solvent and towel, OO in dry microcapsules, OO in glycerin solvent and towel, and the control. The treatments were applied weekly for 4 wk during the fall season. The rates of acaricide efficacy, weekly mite fall, bee mortality, colony survivorship, and strength, were determined for each of the treatments. All formulations, with the exemption of OO microcapsules, were effective at controlling infestations of V. destructor. The most effective formulations were T dust (96.6%), T glycerin (92.4%), and OA glycerin (79%). More than 85% of the mites were killed during the first 2 wk of treatment with T formulations, compared to less than 30% for the OA glycerin formulation. The lowest efficacy rate was for OO microcapsules (21.3%), and the only treatment that significantly increased bee mortality was OA glycerin. The rates of winter colony survival and honey bee populations were related to the varroacidal efficacy of the formulations. The implications of these findings are discussed.

New insights into the use of a mite count reduction test for the detection of therapeutic acaricide efficacy in Psoroptes ovis in cattle

When used for the evaluation of drug efficacy against Psoroptes ovis, the diagnostic performance of different sampling strategies for a mite count reduction test (MCRT) remains unclear. In the present study, a novel simulation framework was constructed that accounted for relevant biological features of P. ovis infestations in cattle and that was parameterized with field data from 16 farms (154 animals). Second, this framework was applied to explore the impact of study specific factors (number of animals, number of sampled lesions, and number of scrapings per lesion) and biological factors (mite infestation intensity and size of lesions) on the diagnostic performance of MCRT. Its outcome provided a basis to determine the diagnostic performance of MCRT when it was applied according to the World Association for the Advancement in Veterinary Parasitology (WAAVP) and the European Medicine Agency (EMA) guidelines, and to formulate recommendations to ensure a good diagnostic performance of the MCRT. For both guidelines, the MCRT allowed to correctly detect (power 80%) reduced and normal efficacy when the therapeutic efficacy was <70%, and ≥95%, respectively. The results highlighted a reliable diagnostic performance of the MCRT when performed as recommended by WAAVP and EMA for the detection of normal drug efficacy. When used for the detection of reduced efficacy, therapeutic efficacies between 70% and 90% could not be detected with sufficient reliability. The diagnostic performance can be improved by increasing the total number of skin scrapings (increasing the number of animals, number of sampled lesions and/or number of samples per lesion). In order to help researchers and veterinarians to optimize the design of the MCRT to their field settings, the findings were translated into a simple tool.

Comparison of Tick Control and Antibiotic Use Practices at Farm Level in Regions of High and Low Acaricide Resistance in Uganda.

Uganda has experienced tick acaricide resistance in the livestock sector. With increase in incidence of tick-borne diseases (TBDs), use of antibiotics for control of TBDs and other opportunistic diseases has raisedserious concerns. The purpose of this study was to compare the farmers' tick control and antibiotic use practices on farms in regions of low (LARA) and high (HARA) tick acaricide resistance in Uganda, determine the prevalence of antibiotic residues in milk from both regions, and identify factors associated with antibiotic residues in milk. One representative district was selected from each region from which 10 farms were randomly selected. Delvotest SP-NT® test kit was used to detect antibiotic residues in milk. Half-body tick counts and acaricide efficacy tests were performed. Majority (70%) of HARA's respondents reported a corresponding increase in a monthly incidence of TBDs with an average of 3.2 cases of TBDs treated per farm compared to 0.2 cases in LARA. East Coast fever (ECF) was identified as the most common TBD in both regions, though cases of coinfection were more common in HARA. Half of HARA's respondents reported a corresponding increase in the use of antibiotics on their farms due to tick resistance compared to LARA. Antibiotics were the most used drugs on farms in both regions with oxytetracycline being the commonly used antibiotic. Ticks from HARA were resistant to deltamethrin, amitraz, and coformulation (chlorpyriphos and cypermethrin) while resistance against deltamethrin was confirmed in LARA. HARA farms had a significantly higher prevalence of antibiotic residues (21.25%) in raw milk than in LARA (4%) farms (p < 0.05). Acaricide resistance and practice of reading drug use instructions were significantly associated with antibiotic residues in milk at farm level. Overall, the study provides vital information linking acaricide resistance to antibiotic use practices, consequently leading to antibiotic residues in milk.

Nanoencapsulation of clofentezine with enhanced acaricidal activity against the two spotted mite, Tetranychus urticae Koch (Acari: Tetranychidae)

Nanoencapsulation of an acaricide, clofentezine, was investigated through a simple and green route using polyethylene glycol (PEG). In comparison to conventional formulations of clofentezine, clofentezine nanocapsules (Clo@NPs) showed improved persistence and solubility. TEM showed spherical nanoparticles that were 230 ± 20 nm. The LC50 values for clofentezine and Clo@NPs against adults were 297.65 and 88.44 µg a.i./mL, respectively. Controlled release experiments showed that Clo@NPs releases the active ingredient over a prolonged period. The results showed that the acaricidal efficacy of nanoformulated clofentzine was improved. The nanoparticle formulation will be more economical and environment friendly to apply compared to traditional formulations.

Study on ruminant tick infestation, phytochemical analysis and in vitro acaricidal effect of &lt;i&gt;Calpurnia aurea&lt;/i&gt; and &lt;i&gt;Otostegia integrifolia&lt;i&gt; extracts on &lt;i&gt;Amblyomma variegatum&lt;/i&gt;

Ticks limit the productivity of livestock through decreased production, reproduction, increased mortality, downgrading and rejection of hides and skin. A cross-sectional study was conducted to estimate the prevalence of tick infestation in ruminant while experimental study was used to evaluate the in-vitro acaricidal efficacy of methanolic extracts: Calpurnia aurea and Otostegia integrifolia and the phytochemicals present in those extracts at different concentrations (200, 100, 50, 25, 12.5 and 6.25 mg/ml) against Amblyomma variegatum. Adult immersion was used for the in-vitro acaricidal efficacy test and plant extracts were subjected to qualitative phytochemical screening for the presence or absence of secondary metabolites using standard procedures. Out of the 160 goats, 152 sheep and 121 cattle, 23 (14.4%), 44 (28.9%) and 28 (23.1%) were found to be positive for tick infestation, respectively. The incidence of tick infestation was significantly different (p&lt;0.01) among ruminants. Five tick spp. were identified: A. variegatum, A. gemma, R. decoloratus, R. evertsi evertsi and R. pulchellus. Extract of C. aurea and O. integrifolia was found to contain alkaloids, saponins, phlobatannin, steroids, phenolic, flavonoids, glycosides and tannins. However, both plants were found negative for triterpens. Extracts of C. aurea and O. integrifolia at 200 and 100 mg/ml concentrations showed a significantly higher (p&lt;0.05) acaricidal activities compared to other treatments at 24 hrs post exposure. Mortality of ticks was increased with the increased dosage (concentration) and exposure time after treatment. Extracts of C. aurea showed a significantly higher (p&lt;0.05) tick mortality (52%) compared to those of O. integrifolia (27%). This is a promising finding to have alternative means of treatment and to substitute the use of synthetic drugs which have a wide spread drug resistance especially in developing countries like Ethiopia.&#x0D; Key words: Calpurnia aurea; in-vitro test; Otostegia integrifolia; Phytochemical screening; Tick infestation

Optimization of the microemulsion formulation of curcuma oil and evaluation of its acaricidal efficacy against Tetranychus cinnabarinus (Boisduval) (Acari: Tetranychidae)

The optimization of the microemulsion formulation of curcuma oil and its acaricidal efficacy against T. cinnabarinus were determined by spray bioassay and repellence bioassay in the laboratory. In this study, we found that the microemulsion formulation had the advantages of solubilization, high transfer efficiency, stability, safety and facilitated penetration into the tissues of T. cinnabarinus . Therefore, the formulation is a promising candidate as a botanical acaricide of crops. • The best microemulsion formulation of curcuma oil was obtained. • The microemulsion formulation solved poor stability and solubility of curcuma oil. • The microemulsion formulation increase acaricidal efficacy. The microemulsion formulation (hereafter formulation) of curcuma oil and its acaricidal efficacy against Tetranychus cinnabarinus Boisduval (Acari: Tetranychidae) were optimized in the laboratory to evaluate their spray effectiveness of oviposition inhibition and repellence. Ethovision XT6 was used to analyse the effects of the sublethal concentrations (LC 20 ) of curcuma oil and the formulation on the behaviors of T. cinnabarinus . The results showed that Tween-80 was the best surfactant, Isopropanol was the best co-surfactant and K m = 2:1 was the best condition for the formulation. The prepared microemulsions are stable under conditions of centrifugation and incubation for extended periods. The results showed that the effect of the spray bioassays of the formulation against T. cinnabarinus continuously increased during the experiment, but for curcuma oil almost no longer increase observed when the exposure time went beyond 24 h. Moreover, compared with curcuma oil (LC 50 = 0.716%), the spray bioassay of the formulation (LC 50 = 0.035%) was stronger against T. cinnabarinus . The repellency of the formulation to T. cinnabarinus was stronger with increasing exposure time, but that of curcuma oil declined after 12 h of exposure. The mobile distance of T. cinnabarinus treated with the formulation continuously declined during the experiment but that due to the curcuma oil almost no longer declined when the treatment time reached 12 h. The maximum mobile frequency of T. cinnabarinus treated by curcuma oil and the formulation was recorded at 6 h and 12 h, respectively. Thus, the formulation is a promising candidate as a botanical acaricide of green vegetables.

The First Study for The Acaricidal Activity of Alcoholic Extracts of Adiantum capillus-veneris and Funaria hygrometric against Argas persicus

The present study was conducted to investigate the acaricidal activity of ethanolic and methanolic extracts of two Cryptogams plants, namely Adiantum capillus-veneris (fern plant) and Funaria hygrometrica (moss plant) at different concentrations (1%, 2%, 3%, and 4%) on semi-fed females of Argas persicus (away from their hosts) collected from the field. The percentages of mobile, immobile, and dead females were recorded two-day intervals for 30 days after treatment with all extracts assayed at different concentrations, using the dipping method. The results indicated that all extracts at different concentrations caused a significant decrease in the percentages of mobile ticks and a significant increase in the percentages of dead ones when compared with the control. The acaricidal efficacy of A. capillus-veneris and F. hygrometrica extracts may be attributed to their contents of many active phytochemical constituents that having high potential against ticks. At the highest concentration (4%), the percentage of tick mortality for methanolic extract was more efficient than ethanolic one for both plants recording 100% efficiency for A. capillus-veneris and 50% for F. hygrometrica. So, we recommended using A. capillus-veneris methanolic extract at 4% as a herbal pesticide against A. persicus which have all characters of ideal pesticides; effective (100% acaricidal activity), easily available, cheap, biodegradable (eco-friendly), and do not cause mammalian toxicity.