Acaricidal Effect Research Articles

Lemongrass (Cymbopogon citratus) essential oil: an eco-friendly and fast-acting acaricide against the grain pest mite Aleuroglyphus ovatus

ABSTRACT This study was designed to evaluate the acaricidal effect and the mode of action of lemongrass essential oil (LEO) against Aleuroglyphus ovatus. Contact and fumigant mortality indicated that LEO had higher acaricidal activities at a low concentration, and the acaricidal action of LEO was significantly more effective by contact effects than by fumigant bioassay. Repellent rate against A. ovatus at different concentrations of LEO increased with application time. Observation on the toxic symptoms revealed that almost all mites were in immobilized type (IM type) in 30 min, but the symptom of knock-down type (KD type) appeared later. Cuticles of mites killed by LEO exhibited obvious colour change and deformation. Detoxification enzyme activity assay showed that glutathione S-transferase (GST) activity increased in mites treated by LEO compared to the controls. LEO increased catalase (CAT) activity of A. ovatus but inhibited superoxide dismutase (SOD) after 20 h. LEO also increased nitric oxide synthetase (NOS) and inhibited acetylcholine esterase (AChE) activities. Moreover, LEO acted as a fast-acting neurotoxin on A. ovatus. Our results suggest that LEO has an acaricidal potential and is a promising agent in control of A. ovatus.

Study of Eucalyptus pauciflora L. characteristics from Algeria and its impact on the mite affecting honeybees Apis mellifera

Essential oils play a crucial role in biological control against parasites threatening the beekeeping stock, both in Algeria and globally. Their appropriate use helps reduce the adverse effects of chemical products on human health and the environment. The purpose of this study is to analyze the components of Eucalyptus pauciflora essential oil grown in Algeria and to evaluate its impact on the marine shrimp Artemia salina and the mite Varroa destructor, while also comparing it to other species of Eucalyptus from the same region namely, Eucalyptus robusta, globulus, sideroxylon, and amygdalina, which have been examine in previous research. Steam distillation of fresh leaves from Eucalyptus pauciflora yielded 0.73% essential oils. This plant contains a total of thirty-nine chemical compounds, among which the most significant are 1,8-cineole (57.45%), β-cymene (5.44%), spathulenol (5.38%), trans-verbenol (4.31%), and α-pinene (3.11%). A lethality test on brine shrimp (BSL) revealed that Eucalyptus pauciflora exhibits toxicity with a median lethal concentration (LC50) of 53.51 ppm. Field trials conducted on hives infested with Varroa destructor showed that the acaricidal effect of Eucalyptus pauciflora is superior to that of amygdalina and sideroxylon species, but inferior to that of globulus and robusta species, all sourced from the same herbarium (Draa Naga) in northeastern Algeria. The results of this research highlight the benefits of Eucalyptus essential oils to be integrated into the formulation of natural acaricides that are environmentally friendly to combat Varroa destructor infestation.

Investigation of the in-vitro lethal effect of spilanthol on demodex and finding the most effective dose.

Demodex species are associated with many dermatological diseases, so an acaricidal agent that is effective against them and safe for skin applications may benefit many diseases. This study aims to investigate the anti-demodex potential of spilanthol, a product obtained from the Spilanthes Acmella plant, by determining the minimal effective dose for the first time in the literature. Demodex mites were obtained from 70 patients with standard superficial skin biopsy. Spilanthol extract was used at 1%, 2%, 3%, 4%, and 5%. Standard immersion oil was used for the negative control, and permethrin 5% was used for the positive control group. The dependent variable is the survival time of the mite. Comparisons with the negative control group, the anti-demodex effect demonstrated itself in all groups, creating a statistically significant difference (p < 0.001). The positive control group, had 3%, 4%, and 5% spilanthol rates which were very similar to the results with 5% permethrin (p > 0.05). Higher concentrations than 3% did not make any additional contribution to survival times. This is the first attempt to show the dose-dependent acaricidal effect of spilanthol on demodex mites. Even the 3% dose shows similar results to 5% permethrin, and no additional effect increase was observed at higher doses. Therefore, in vivo, studies may be planned with a 3% spilanthol dose for further studies.

Acaricidal potential of essential oils on Rhipicephalus linnaei: Alternatives and prospects

The acaricidal potential of various essential oils (EOs) has been evaluated based on their benefits in tick control. This study aimed to investigate the tick-killing activity of Pogostemon cablin “patchouli,” Cymbopogon martinii “palmarosa,” and Cymbopogon flexuosus “lemongrass” EOs on Rhipicephalus linnaei. Engorged females were collected from domiciled and non-domiciled dogs from Jataí city, Goiás state, to obtain larvae and nymphs in a controlled environment. Two commercial EOs brands were used in this study in different EOs concentrations (2.5, 5, 10, and 20 mg/mL), and was tested by immersion of larvae and nymphs. In the in vitro evaluation of EOs toxicity against R. linnaei larvae, 100 % mortality was achieved with 10 mg/mL of P. cablin oil, whereas mortality rates greater than 98 % were observed with 20 mg/mL of C. martinii and C. flexuosus. In nymphs, high sensitivity was observed, with 100 % mortality achieved using 5 mg/mL of P. cablin and 20 mg/mL of C. martinii and C. flexuosus. The EO of P. cablin “patchouli” demonstrated in vitro toxicity at a lower concentration than the other oils in the two development stages of R. linnaei, and was considered the most efficient and with verified acaricidal activity. Oils of C. martinii “palmarosa” and C. flexuosus “lemongrass” achieved mortality greater than 95 % in larvae and nymphs only at the highest concentration. Therefore, the acaricidal effects of the tested EOs are promising, especially of patchouli oil, which promoted high mortality at a low concentration (LC90 of 2.21 mg/mL).

Deltamethrin's Effect on Nitrogen-Fixing Nodules in Medicago truncatula.

Deltamethrin is used against plant pests (e.g., mites and ants) and, in farm animals, against biting insects because of its acaricidal and repellent effects against ticks, thus protecting the sheep and cattle from the transmission of pathogens. However, its impact on the environment still needs to be fully evaluated. This study evaluates the impact of this pyrethroid on the nitrogen-fixing nodules in Medicago truncatula, a model legume. This research compares nodular biomass and root weight between a deltamethrin-treated section and an untreated control section of this legume. Our results indicate a significant reduction in the biomass of nitrogen-fixing nodules in the treated grove, suggesting that deltamethrin negatively affects the symbiotic relationship between M. truncatula and nitrogen-fixing bacteria. This reduction in nodule formation can impair soil fertility and plant growth, highlighting an ecological risk associated with pyrethroid's use in livestock farming. These findings underscore the need for a shift towards Green Veterinary Pharmacology (GVP), which promotes environmentally sustainable practices in managing livestock health. By minimizing our reliance on harmful chemical treatments, GVP offers viable solutions to protect and enhance ecosystem services such as biological nitrogen fixation that are essential for maintaining soil health and agricultural productivity.

Acaricidal potential of Bidens pilosa in the control of the red palm mite

Raoiella indica Hirst, 1924 (Prostigmata: Tenuipalpidae), is one of the leading pest mites on plants of the Arecaceae family, especially palm and banana trees. This species has a high reproductive capacity and rapid dissemination, but the control methods available for this species are still limited. Therefore, this work aimed to evaluate the acaricidal effect of blackjack (Bidens pilosa) on adult individuals of R. indica. The experiment was conducted in a completely randomized design, using the plant structures of blackjack to prepare the extracts. The experimental units consisted of coconut leaf discs (4 cm), with moistened cotton at the bottom of the Petri dish (10.0 × 1.2 cm), and around the disc to maintain turgidity and prevent mites from escaping. Spraying was carried out on 12 adult females of R. indica per sample unit, with seven repetitions for each concentration, using an airbrush with a constant pressure of 1.3 psi and 1 mL of solution per repetition plate. The acaricidal effect was evaluated 12, 24, 36, 48, 60, and 72 hours after spraying. The mortality of R. indica was proportional to the increase in the concentration of the blackjack plant extract, and the lethal concentrations obtained, CL50 and CL 90, were estimated between 1.49% and 4.19%, indicating the acaricidal potential of B. pilosa. Phenolic compounds were the majority of compounds found in this study.

Functional analysis of novel cystatins from Haemaphysalis doenitzi and evaluation of their roles in cypermethrin and λ-cyhalothrin resistance

Currently, the primary strategy for tick control relies on chemical agents. Pyrethrins, which are botanically derived compounds, have demonstrated efficacy in controlling ticks without posing a risk to human or animal health. However, research into pyrethrins' metabolic mechanisms remains sparse. Cystatin, as a reversible binding inhibitor of cysteine protease, may be involved in the initiation of pyrethrin detoxification of Haemaphysalis doenitzi. In this study, two novel cystatins were cloned, HDcyst-3 and HDcyst-4, the relative expression of which was highest in the Malpighian tubules compared with the tick midguts, salivary glands, and ovaries. Prokaryotic expression and in vitro studies revealed that cystatins effectively inhibit the enzymatic activities of cathepsins B and S. RNAi results showed that the reduction of cystatins significantly decreased the engorgement weight, egg mass weight, and egg hatching rate of adult female ticks, and prolonged feeding time by two days. The control rate of rHDcyst-3 and rHDcyst-4 protein vaccination against female adults were 55.9% and 63.2%, respectively. In addition, the tick immersion test showed that cypermethrin and λ-cyhalothrin had significant acaricidal effects against adult unfed H. doenitzi. The qPCR result indicated that compared with the control group, the expression of HDcyst-3 and HDcyst-4 was markedly decreased in the sublethal cypermethrin and λ-cyhalothrin group at LC50. Enzyme activity showed that cypermethrin and λ-cyhalothrin could significantly induce the activities of glutathione S-transferase (GST), carboxylesterase (CarE), and acetylcholinesterase (AchE). The aforementioned results provided indirect evidence that cystatin plays an important role in pyrethrin detoxification and provides a theoretical basis for future acaricide experiments and pest management.

Acaricide effect of plants from the Brazilian savanna on a population of Rhipicephalus microplus with phenotypic resistance to cypermethrin and trichlorfon

Rhipicephalus microplus is among the most important ectoparasites for livestock. The use of synthetic acaricides has raised some concerns due to the selection of tick populations that are resistant to acaricides and environmental contamination. Therefore, plant extracts have been used as alternatives for the treatment of animals infested with ticks. In this study, R. microplus populations from seven different dairy farms were collected and assessed for their resistance to the acaricides cypermethrin or trichlorfon. Larvae of the most resistant population were used in assays to evaluate the acaricide effect of leaf extracts from plants of the Brazilian savanna. The most active extracts were also tested against fully engorged females. Among seven tick populations, five and three showed resistance level ≥ III for cypermethrin or trichlorfon, respectively. The most resistant tick population was evaluated in mortality assays with the plants Piptadenia viridiflora, Annona crassiflora, Caryocar brasiliense, Ximenia americana, and Schinopsis brasilienses. The ethanolic extracts of C. brasiliense, X. americana and S. brasilienses showed higher larvicidal effects in comparison to the other extracts and cypermethrin. The ethanolic extract of X. americana showed 60.79 % efficacy against fully engorged females of the acaricide resistant tick strain. The ethanolic extracts of C. brasiliense, X. americana, and S. brasilienses showed peaks in HPLC-DAD, indicating the presence of tannins and flavonoids. Three of the plants showed promising results and should be explored in further studies to develop novel tools to control R. microplus in cattle.

The use of essential oils as an alternative for the control of Tetranychus urticae (Acari: Tetranychidae)

Considering that the use of essential oils is a promising technique and a valuable alternative in the control of unwanted organisms, this study aimed to chemically characterize the essential oil of Acanthospermum australe (Loefl.) O. Kunze (Asteraceae) through gas chromatography, as well as to evaluate the repellent and acaricidal effect of the essential oils from A. australe and Baccharis psiadioides (Less.) Joch.Müll (Asteraceae) against Tetranychus urticae Koch (Tetranychidae). For the repellency test, concentrations of 0.25, 0.5 and 1% were used for both oils, and concentrations of 10 μL/L(air) and 20 μL/L(air) to evaluate acaricidal effects. Eight compounds were identified in the essential oil of A. australe, with thymyl isobutyrate (63.4%) being the major compound, followed by thymol (13.4%) and thymyl 2-methylbutyrate (4.96%). The results demonstrated higher repellency to the essential oil of A. australe at a concentration of 0.5%, followed by B. psiadioides at a concentration of 1%. The mortality rate of TSSM exceeds 90% when exposed to both tested concentrations of the essential oil of A. australe proving effective in both cases.

Pharmacological and Phytochemical Potential of Andropogon muricatus: A Review

Many medicinal plants have been utilized as medications since ages ago. Chemical components extracted from such plants have been used historically in traditional Unani medicine, the Siddha and other medical systems for a variety of ailments. Among them is Andropogon muricatus, a member of the family Poaceae, better known by its common name, vetiver. It contains a variety of organic components with significant therapeutic benefits for a range of illnesses, including mosquito repellent, anxiolytic, acaricidal, hypoglycaemic, antidepressant, antidiuretic, sedative, antifungal, and nervine effects. This plant’s roots serve as cooling. When it comes to oil extraction—which is used in food and beverages, spas, home appliances, and medicine—root systems are the most valuable parts of the plant. It is indigenous in Bangladesh, China, Japan, the Bonin Islands, Nepal, the Philippines, and Sri Lanka in the Asian continent. Australia and Spain were first exposed to it in Europe and Oceania. Substances of a chemical nature that have been extracted from the plant’s overall various sections have previously been the subject of numerous pharmacologic and medicinal studies.

Synergistic action and mechanism of scoparone, a key bioactive component of Artemisia capillaris, and spirodiclofen against spider mites.

Plants have numerous defensive secondary metabolites to withstand insect attacks. Scoparone, which is extracted from the medicinal plant Artemisia capillaris, has potent acaricidal effects on Tetranychus cinnabarinus. Spirodiclofen, derived from a tetronic acid derivative, is a potent commercial acaricide that is extensively used globally. However, whether scoparone has synergistic effects when used in conjunction with spirodiclofen and the underlying synergistic mechanism remains unclear. Scoparone exhibited a potent synergistic effect when it was combined with spirodiclofen at a 1:9 ratio. Subsequently, cytochrome P450 monooxygenase (P450) activity, RNA-Seq and qPCR assays indicated that the enzyme activity of P450 and the expression of one P450 gene from T. cinnabarinus, TcCYP388A1, were significantly inhibited by scoparone and spirodiclofen + scoparone; conversely, P450 was activated in spirodiclofen-exposed mites. Importantly, RNAi-mediated silencing of the TcCYP388A1 gene markedly increased the susceptibility of spider mites to spirodiclofen, scoparone and spirodiclofen + scoparone, and in vitro, the recombinant TcCYP388A1 protein could metabolize spirodiclofen. Molecular docking and functional analyses further indicated that R117, which is highly conserved in Arachnoidea species, may be a vital specific binding site for scoparone in the mite TcCYP388A1 protein. This binding site was subsequently confirmed using mutagenesis data, which revealed that this binding site was the sole site selected by scoparone in spider mites over mammalian or fly CYP388A1. These results indicate that the synergistic effects of scoparone and spirodiclofen on mites occurs through the inhibition of P450 activity, thus reducing spirodiclofen metabolism. The synergistic effect of this potent natural product on the detoxification enzyme-targeted activity of commercial acaricides may offer a sustainable strategy for pest mite resistance management. © 2024 Society of Chemical Industry.

The efficacy of antiparasitic drug based on Lufenuron, Moxidectin, and Praziquantel against ixodidosis in dogs

The purpose of the research is to study the efficacy of antiparasitic drug based on Lufenuron, Moxidectin, Praziquantel against ixodidosis in dogs under natural conditions and during experimental infection with ixodid ticks.Materials and methods. The experiments used the drug in tablet formulation containing Lufenuron in 320 mg, Moxidectin in 9.6 mg and Praziquantel in 160 mg. To study the preventive and therapeutic acaricidal effect of the drug against ixodid ticks in the country part of the Karachaevsky District of the Karachay-Cherkess Republic, two groups (10 dogs each) were formed of Alabai dogs or outbred dogs with a body weight of 16–76 kg. The dogs of the first experimental group were administered the drug in tablets. The dogs of the second group served as controls and were not treated. The experiment used clinically healthy dogs of both sexes over 6 weeks of age, spontaneously infected with Ixodidae. Animals were selected so that they were not exposed to drugs for at least 1 month prior to the experiment. The animals were kept under normal conditions throughout the experiment and received their usual food. Antiparasitic tablets were administered to the dogs individually, once, orally, mixed with food at a dose of 1 tablet per 16–32 kg of body weight. The ixodid infection was diagnosed in the dogs by clinical examination. The genus of Ixodidae was determined by typical morphological characteristics. The drug efficacy was evaluated based on reduced number or absence of ticks on the treated animals (experimental) versus the untreated animals (control). Before the experiment and after the drug, the animals were examined every hour for 48 hours, and condition, separation, separation time from the start of the drug and death of the ticks were recorded; the dogs were then examined every 5–7 days for two months.Results and discussion. The article presents study data on antiparasitic drug efficacy against ixodidosis in dogs spontaneously infected with Ixodes ricinus, I. persulcatus, and Dermacentor reticulatus. The result of the studies found that the antiparasitic drug (active substances were Lufenuron, Moxidectin, and Praziquantel) had a therapeutic effect that was recorded on day 5 after treatment and was 90%. The preventive efficacy was also above 70%: on day 7 and 14, this value was 90.0 and 86.9%, respectively, which indicated the duration of the preventive effect for 25–28 days. To fully evaluate the acaricidal efficacy against ixodidosis, studies were conducted on experimentally infected animals. Forty percent efficacy was determined at 48 hours after the drug; at 2 weeks after the drug, 90 %, 98.5 and 100 % efficacy were determined against ixodidosis in the dogs at 24 hours, 48 and 72 hours after the transfer of ticks, respectively. At 4 weeks after the drug, 100 % efficacy was determined against ixodidosis in the dogs at 24, 48 and 72 hours after the transfer of ticks, respectively.

Comparative analysis of essential oil efficacy against the Asian longhorned tick Haemaphysalis longicornis (Acari: Ixodidae).

This study evaluated the potential repellent and acaricidal effects of 4 essential oils (clove, eucalyptus, lavender, and mint) against the Asian longhorned tick Haemaphysalis longicornis, a vector of various tick-borne diseases in medical and veterinary contexts. Selected for their potential repellent and acaricidal properties, the 4 essential oils were tested on adult and nymph H. longicornis ticks at different concentrations. The experiment assessed mortality rates and repellency, particularly during tick attachment to host skin. There was a significant increase (p&lt;0.05) in tick mortality and repellency scores across all groups. At a 1% concentration, adult tick mortality ranged from 36% to 86%, while nymph mortality ranged from 6% to 97%. Clove oil exhibited notable efficacy, demonstrating high mortality rates of nymphs and adults. Clove oil also displayed strong repellency properties, with a repellency index of 0.05, surpassing those of mint, eucalyptus, and lavender oils. Clove oil showed the highest effectiveness in deterring nonattached adult ticks (90%) and nymphs (95%) when applied to skin. Clove oil was the most effective against adult and nymph ticks, achieving mortality rates of 86% and 97%, respectively, and led to the highest nonattachment rates when applied to skin. In conclusion, essential oils such as clove, eucalyptus, lavender, and mint oils present promising results for tick population control.

Effect of Mammea americana Aqueous Extract on the Control of the Coffee Red Spider Mite

The coffee red spider mite, Oligonychus ilicis, stands out as one of the main pests of Conilon coffee. The use of synthetic chemical control has led to an increase in the population of this mite and a reduction in its natural enemies. Aiming to find viable alternatives, this study aimed to evaluate the acaricidal potential of “abricó” peel extract, Mammea americana, in the management of O. ilicis. Each treatment consisted of 7 repetitions, with 10 individuals per repetition. They were placed in Petri dishes (10.0 x 1.2 cm), containing coffee leaf disks (4 cm diameter) inside, and moistened cotton at the bottom of the dish and around the disks. The peels of M. americana were dried, crushed, and diluted in aqueous solution to obtain extracts at concentrations of 2; 2.57; 3.30; 4.24; 5.45; and 7 %. The application was done by spraying, using an Alfa 2 model airbrush connected to a compressor calibrated with a constant pressure of 1.3 psi. 1 mL of solution of each concentration was applied for each repetition. Distilled water and the surfactant Tween® 80 (0.05 % v/v) were used as control treatments. The acaricidal effect was evaluated 24, 48, and 72 hours after spraying, and the lethal concentrations LC50 and LC90 were calculated. The results of the toxicity tests indicated an increase in the mortality of O. ilicis with the increase in the concentrations of aqueous extracts of M. americana, resulting in 100 % mortality. The LC90 was estimated at 3.83 %. In the chemical analysis of the M. americana extract, the presence of phenolic acids, tannins, and flavonoids was observed at concentrations of 39.150, 40.783, and 0.0349 mg-1, respectively. We conclude that the aqueous extract of M. americana peels demonstrated acaricidal potential in a controlled environment for the coffee red spider mite.

Potential Repellency and Toxicity of Hexane Extracts from &lt;i&gt;Cyperus rotundus&lt;/i&gt; to &lt;i&gt;Tetranychus urticae&lt;/i&gt; Koch. (Acari: Tetranychidae)

The objective of this work was to evaluate the acaricidal and repellency effect of Cyperus rotundus extract, an important weed plant, on Tetranychus urticae adults. Randomized complete block with 4 replicates was adopted. The hexane C. rotundus extract was obtained from tubers using the Soxhlet apparatus, then diluted to 5 concentrations (C1-100%, C2-50%, C3-25%, C4-10% and C5-1%), and a control (distillate water). Results showed that five concentrations caused significant mortality of T. urticae adults 24, 48 and 72 hr after treatment. The higher mortality was observed with C1 concentration of C. rotundus extract 72 hr after treatment (97%). Three concentrations C1, C2 and C3 showed a repellent effect on T. urticae adults. The repellence index ranged from 25 to 55% for C3 and C1, respectively. The present study demonstrated that the C. rotundus extracts could be an effective acaricide on T. urticae adults since the LC50 obtained was 30.95%.

SEMENTES DE MAMÃO EM DIFERENTES ESTÁGIOS DE DESENVOLVIMENTO SÃO EFICAZES NO CONTROLE DO ÁCARO VERMELHO DA PALMEIRA?

Objective: To evaluate the acaricidal potential of papaya fruit seed (C. papaya L.) extracts at different phenological stages of development on the red palm mite. Methods: Extracts from green and ripe seeds, diluted at different concentrations, were sprayed on adult mites in a completely randomized design using Petri dishes with discs of dwarf coconut leaf. The acaricidal effect was assessed at intervals of 12 hours up to 72 hours after spraying. Results and Conclusion: The mortality of Roiella indica was proportional to the increase in extract concentrations for both green and ripe papaya fruit seeds. It was concluded that aqueous extracts from green and ripe papaya fruit seeds exhibit acaricidal activity against adult red palm mites under laboratory conditions. Research Implications: Papaya seeds at different stages effectively controlled red palm mites under laboratory conditions. Originality/Value: This research contributes by exploring the potential of an agricultural residue as a pest control agent in agriculture and demonstrating its potential for more sustainable agricultural practices.

The effectiveness of acaricidal drugs in bovine psoroptosis

The report presents the results of acaricides using from the macrocyclic lactones group and complex drug administration which includes deltamethrin, diflubenzuron and piperonyl butoxide by psoroptic scab of cattle. There was research at the beefproducing farm (Aberdeen Angus breed). It was four groups (n=10 by each). Animals of the 1st experimental group have received «Meradoc» drug (doramectin 1%, subcutaneous introduction, the neck area), 2d experimental group – «Ivermec» drug (ivermectin 1%, 1 ml per 50 kg, subcutaneous introduction, the neck area), 3d experimental group – «Deltsid 7.5» by single dose (15 ml per 100 kg) by the application on skin vertebral from the head to the tail. The 4th group was control without acaricidal treatment. It was found the single using of macrocyclic lactones groups’ drugs were destroyed only the larval, nymphal and imaginal phases of acarian Psoroptes without ticks’ eggs extermination. The scraping was included ticks’ eggs on 7th day after «Deltsid 7.5» drug using, but it wasn’t detected any larval, imaginal phases and ticks’ eggs on the 14th, 21st and 28th days after beginning of animal’s treatment. Moreover, to the 28th days there were registered the hair restoration and the skin in affected areas without compaction and folding. The using of complex drug «Deltsid 7.5» is more effective treatment of psoroptic scab of cattle. This drug has the acaricidal effect on the preimaginal phases Acariformes. There were blocked the enzymes activity which destroy the drug’s effect. To take on the Acariformes resistibility by acaricides it should be control the quality of anti-acaricidal treatments by microscopy of skin scrapings. The recommendation in the case of the positive result’s getting is the treatment alternation.

Discovery of Pesticide Candidates from Natural Plant Products: Semisynthesis and Characterization of Andrographolide-Based Esters and Study of Their Pesticidal Properties and Toxicology.

To explore the use of nonfood plant-derived secondary metabolites for plant protection, a series of ester derivatives for controlling the major migratory agricultural pests were obtained by structural modification of andrographolide, a labdane diterpenoid isolated from Andrographis paniculata. Compound Id showed good insecticidal activity against the fall armyworm Spodoptera frugiperda Smith. Compounds IIa (LC50: 0.382 mg/mL) and IIIc (LC50: 0.563 mg/mL), the acaricidal activities of which were, respectively, 13.1 and 8.9 times that of andrographolide (LC50: 4.996 mg/mL), exhibited strong acaricidal and control effects against Tetranychus cinnabarinus Boisduval. Against Aphis citricola Van der Goot, compounds IIIc and IVb displayed 3.9- and 3.7-fold pronounced aphicidal activity of andrographolide. Effects of compound Id on three protective enzymes (superoxide dismutase, peroxidase, and catalase) of S. frugiperda were also observed. The obvious differences of epidermal cuticle structures of mites treated with compound IIa were determined by scanning electron microscopy. Structure-activity relationships indicated that 14-ester derivatives of andrographolide showed potential insecticidal/acaricidal activities and can be further utilized as lead compounds.

ОПЫТ ЛЕЧЕНИЯ ЛАБОРАТОРНЫХ КРЫС ПРИ НОТОЭДРОЗЕ

The purpose of the study is to compare the acaricidal effectiveness of the drugs Dironet spot-on and Delcid for notoedrosis of laboratory rats (Wistar breed). To evaluate the therapeutic effectiveness of the drugs, two groups of white rats (Wistar breed) of 25 animals each (with approximately the same body weight – 250 g), spontaneously infested with Notoedres musculi mites, were selected. The diagnosis was made based on characteristic symptoms and microscopy results of deep skin scrapings using the vital method. Acarological studies were carried out in the scientific laboratory of the department of the Federal State Budgetary Educational Institution of Higher Education Verkhnevolzhsky State Agrobiotechnological University (Ivanovo) in 2020–2022. In the first experiment, when using Dironet spot-on (on the skin indivi-dually, by drop method in a dose of 0.1 ml (three drops per head), twice with an interval of 10 days), the drug showed high effectiveness against ticks (after the first treatment EI = 20 %, EE = 80), and after the second – EI = 0%, EE = 100 %. After the second treatment, no parasites were found in skin scrapings. In the second experiment, when using Delsid (in the form of manual total spraying at a dose of 0.005 % (according to DB), twice with a difference of 10 days), the drug turned out to be less effective than the first. After the first treatment, EI = 40 %, EE = 60 %, after the second – EI = 12 %, EE = 88 %. After the second treatment, mites were found in skin scrapings on 12 % of treated heads. After using acaricides, the animals were observed daily, taking into account their condition, appetite and skin integrity. Microscopic exa¬minations were carried out before and after the use of drugs, as well as every 10 days for two months after the last treatment of animals. Treatment experience indicates that these acaricides are highly effective drugs. They can be used as a means of therapy and prevention for notoedrosis in rats twice with an interval of 10 days.

The potential effect of Garlium GEM HCTM as a tick control agent in cattle.

As resistance to chemical acaricides increases amongst tick populations, investigations of natural remedies that have acaricidal or tick-repellent effects have become essential in the search for alternatives for sustainable tick control. Garlium GEM HC (Garlium), a natural concentrated garlic product, was supplemented in-feed to beef cattle to determine if it could assist in reducing the number of attached ticks on cattle. Two grams of Garlium was supplemented daily to eight Bonsmara steers over 43 days. A second group of eight steers served as controls. All animals were infested with a similar number of Rhipicephalus appendiculatus adults and Rhipicephalus microplus larvae. Subsequently, the number of attached engorged ticks and the hatchability of the tick eggs were determined. Blood samples were collected from the steers for whole blood analyses. The results were analysed using a twosample t-test procedure. Due to large standard deviations observed, most of the tick parameters were only numerically improved. Although not significant, the number of larvae produced by female R. appendiculatus ticks per host was reduced by 23%. Estimated number of R. microplus larvae produced from ticks harvested from Garlium supplemented cattle were reduced by 42.3% (p = 0.10). No adverse effect was observed on haematocrits or haemoglobin concentrations. Garlium reduced segmented neutrophil count in the treatment group, suggesting that the immune system was less challenged. Although not statistically significant, the effect of reducing the number of larvae produced per host for the two tick species by approximately 20% and 40% respectively, may be of economic benefit to commercial cattle farmers.