The insecticidal activity of four medicinal plants against the blowflyLucilia sericata(Diptera: Calliphoridae)

Acaricidal Efficacy of Thirty-Five Egyptian Plants Against the Camel Tick, Hyalomma Dromedarii

PURPOSE

Alternative and affordable tick control strategies are crucial to control and prevent tick bites and tick-borne diseases.

METHODS

In this study, we evaluated the acaricidal efficacy of 35 aqueous plant extracts (17%) against the camel tick, Hyalomma dromedarii.

RESULTS

The phytochemical profile indicated the presence of various secondary substances. Plants were classified into three groups according to their mortality percentage 15 days post-treatment with 17%. This highly effective group (91%-95%) comprised Ocimum basilicum, Mespilus germanica, and Viola alpine followed by Carum carvi, Cucurbita pepo (peel), and Peganum harmala. A moderately effective group (80%-90%) included Acacia nilotica, Apium graveolens, Capsicum annuum, Ceratonia siliqua, Cucurbita pepo (seeds), Equisetum arvense, Eruca sativa, Ginkgo biloba, Plantago psyllium, Phyllanthus emblica, Punica granatum, and Ziziphus spinachristi. The 20 remaining plants were assigned to the less effective group (< 80%). Viscum album (58.3%), which was the least effective reference plant. The high potency of six plant extracts as acaricides may be attributed to the high content of active principles, e.g., phenols, flavonoids, and tannins.

CONCLUSION

All of these highly effective plants are recommended for use as an acaricide, in case of facing acaricidal resistance or limited options for tick control.

Synthesis of eco-friendly layered double hydroxide and nanoemulsion for jasmine and peppermint oils and their larvicidal activities against Culex pipiens Linnaeus

Mosquito-borne diseases represent a growing health challenge over time. Numerous potential phytochemicals are target-specific, biodegradable, and eco-friendly. The larvicidal activity of essential oils, a jasmine blend consisting of Jasmine oil and Azores jasmine (AJ) (Jasminum sambac and Jasminum azoricum) and peppermint (PP) Mentha arvensis and their nanoformulations against 2nd and 4th instar larvae of Culex pipiens, was evaluated after subjecting to different concentrations (62.5, 125, 250, 500, 1000, and 2000 ppm). Two forms of phase-different nanodelivery systems of layered double hydroxide LDH and oil/water nanoemulsions were formulated. The synthesized nanoemulsions showed particle sizes of 199 and 333 nm for AJ-NE and PP-NE, with a polydispersity index of 0.249 and 0.198, respectively. Chemical and physiochemical analysis of TEM, SEM, XRD, zeta potential, drug loading capacity, and drug release measurements were done to confirm the synthesis and loading efficiencies of essential oils' active ingredients. At high concentrations of AJ and PP nanoemulsions (2000 ppm), O/W nanoemulsions showed higher larval mortality than both LDH conjugates and crude oils. The mortality rate reached 100% for 2nd and 4th instar larvae. The relative toxicities revealed that PP nanoemulsion (MA-NE) was the most effective larvicide, followed by AJ nanoemulsion (AJ-NE). There was a significant increase in defensive enzymes, phenoloxidase, and α and β-esterase enzymes in the treated groups. After treatment of L4 with AJ, AJ-NE, PP, and PP-NE, the levels of phenoloxidase were 545.67, 731.00, 700.00, and 799.67 u/mg, respectively, compared with control 669.67 u/mg. The activity levels of α-esterase were 9.71, 10.32, 8.91, and 10.55 mg α-naphthol/min/mg protein, respectively. It could be concluded that the AJ-NE and PP-NE nanoformulations have promising larvicidal activity and could act as safe and effective alternatives to chemical insecticides.

Cytotoxic, Scolicidal, and Insecticidal Activities of Lavandula stoechas Essential Oil

Essential oils (EOs) have recently attracted more interest due to their insecticidal activities, low harmfulness, and rapid degradation in the environment. Therefore, Lavandula steochas (L. steochas) essential oil was assessed for its chemical constituents, in vitro cytotoxicity, and scolicidal, acaricidal, and insecticidal activities. Using spectrometry and gas chromatography, the components of L. steochas EOs were detected. Additionally, different oil concentrations were tested for their anticancer activities when applied to human embryonic kidney cells (HEK-293 cells) and the human breast cancer cell line MCF-7. The oil’s scolicidal activity against protoscolices of hydatid cysts was evaluated at various concentrations and exposure times. The oil’s adulticidal, larvicidal, and repelling effects on R. annulatus ticks were also investigated at various concentrations, ranging from 0.625 to 10%. Likewise, the larvicidal and pupicidal activities of L. steochas against Musca domestica were estimated at different concentrations. The analyses of L. steochas oil identified camphor as the predominant compound (58.38%). L. steochas oil showed significant cytotoxicity against cancer cells. All of the tested oil concentrations demonstrated significant scolicidal activities against the protoscoleces of hydatid cysts. L. steochas EO (essential oil) showed 100% adulticidal activity against R. annulatus at a 10% concentration with an LC50 of 2.34%, whereas the larvicidal activity was 86.67% and the LC50 was 9.11%. On the other hand, the oil showed no repellent activity against this tick’s larva. Furthermore, L. steochas EO achieved 100% larvicidal and pupicidal effects against M. domestica at a 10% concentration with LC50 values of 1.79% and 1.51%, respectively. In conclusion, the current work suggests that L. steochas EO could serve as a potential source of scolicidal, acaricidal, insecticidal, and anticancer agents.

Traumatic sheep myiasis: A review of the current understanding

Myiasis, or the infestation of live humans and vertebrate animals by dipterous larvae, is a health issue worldwide. The economic impact and potential threat to animal health and wellbeing of this disease under the animal husbandry sector is considerable. Sheep are a highly vulnerable livestock category exposed to myiasis (sheep strike), due to several unique predisposing factors that attract flies. The successful mitigation of this disease relies on a thorough understanding of fly population dynamics associated with the change in weather patterns and the evaluation of this disease through different branches of science such as chemistry, molecular biology, and microbiology. The present review provides a summary of the existing knowledge of strike in sheep, discussed in relation to the application of volatile organic compounds, metagenomics, and molecular biology, and their use regarding implementing fly control strategies such as traps, and to increase the resilience of sheep to this disease through improving their health and wellbeing.

Ovicidal Aroma Shields for Prevention of Blow Fly Strikes Caused by Lucilia sericata (Meigen), Diptera: Calliphoridae

The blow fly, Lucilia sericata (Meigen) (Diptera: Culicidae) is a primary facultative ectoparasite controlled by insecticides that have environmental and safety concerns; therefore, its natural and safe control is crucial. L. sericata eggs were subjected to 400 μL of 5% of 24 materials of plant-borne origin. The number of hatched and unhatched eggs were counted 24 h postexposure. Stopmyasis^® expressed the highest ovicidal effect, followed by cedarwood, orange, and tea tree oils. The mean ovicidal results were 46.09-95.24% grouped as Class A, which provided the lowest hatchability rates. Even though benzoin, vanillin, citronella, and camphor oils grouped as Class B provided moderate ovicidal effects (33.69-43.92%), their efficacy differed significantly from those of the treatments in Classes A and C containing the control group and vetiver, eucalyptus, Olbas^®, neem, sunflower, oil blends, patchouli, frankincense, p-menthane-3,8 diol (PMD), lavender, peppermint, cinnamon, calry sag, myrtle, and silicone oil. According to our knowledge, most (19 out of 24) applied materials were used as ovicides against L. serricata for the first time, except orange, eucalyptus, patchouli, cinnamon oils, and six of them were applied as ovicides against pests for the first time. Stopmyasis containing Géraniol and PMD is the drug of choice as an ecofriendly product to prevent blow fly strikes through correct diagnosis and prompt treatment preventing a disastrous and destructive course of the disease and improving quality of life.

Novel Pesticidal Efficacy of Araucaria heterophylla and Commiphora molmol Extracts against Camel and Cattle Blood-Sucking Ectoparasites

Botanical insecticides are promising pest control agents. This research investigated the novel pesticidal efficacy of Araucaria heterophylla and Commiphora molmol extracts against four ectoparasites through treated envelopes. Seven days post-treatment (PT) with 25 mg/mL of C. molmol and A. heterophylla, complete mortality of the camel tick, Hyalomma dromedarii and cattle tick, Rhipicephalus (Boophilus) annulatus were reached. Against H. dromedarii, the median lethal concentrations (LC50s) of the methanol extracts were 1.13 and 1.04 mg/mL and those of the hexane extracts were 1.47 and 1.38 mg/mL, respectively. The LC50 values of methanol and hexane extracts against R. annulatus were 1.09 and 1.41 plus 1.55 and 1.08 mg/mL, respectively. Seven days PT with 12.5 mg/mL, extracts completely controlled Haematopinus eurysternus and Hippobosca maculata; LC50 of Ha. eurysternus were 0.56 and 0.62 mg/mL for methanol extracts and 0.55 and 1.00 mg/mL for hexane extracts, respectively, whereas those of Hi. maculata were 0.67 and 0.78 mg/mL for methanol extract and 0.68 and 0.32 mg/mL, respectively, for hexane extracts. C. molmol extracts contained sesquiterpene, fatty acid esters and phenols, whereas those of A. heterophylla possessed monoterpene, sesquiterpene, terpene alcohols, fatty acid, and phenols. Consequently, methanol extracts of C. molmol and A. heterophylla were recommended as ecofriendly pesticides.

The potential of Apiaceae species as sources of singular phytochemicals and plant-based pesticides

The Apiaceae Lindl. (=Umbelliferae Juss.), which includes several economical important vegetables, herbs, and spices, is one of the most numerous plant family. Umbelliferous crops (namely anise, fennel, carrot, coriander, parsley, etc.) are also valuable sources of botanical flavoring agents and fragrances. In addition, Apiaceae species yield a wide variety of distinctive specialized metabolites (i.e, volatile phenylpropanoids, furanocoumarins, sesquiterpene coumarins, polyacetylenes, and phthalides), some of them been described as uncommon natural phytochemicals exclusive of the family, which offers a great potential for bioprospection. Numerous studies have pointed out the outstanding biological activity of extracts and several classes of phytochemicals from Apiaceae species. Emphasis has been given to essential oils (EOs) and their constituents activities, most likely because this type of plant added value product benefits from a larger acceptance and application potential in integrated pest management (IPM) and integrated vector management (IVM) programs. Several species of the family offer a variety of unique compounds with great potential as biopesticidal and/or synergizing agents. Investigations covering their activity toward agricultural pests and phytopathogens have increased in the last years, nevertheless the interest remains strongly focus on arthropod species, predominantly those acting as vectors of human diseases. From our survey, it is patent the gap of knowledge concerning the potential molluscicidal properties of Apiaceae extracts/phytochemicals, as well as their herbicidal activities against invasive plant species. In this review, we propose to highlight the potential of Apiaceae species as suitable sources of bioactive phytochemicals with great relevance within the frame of plant-based pesticides R&D, and will discuss their applicability in real-world scenarios considering the recent developments regarding the design of stable formulations incorporating Apiaceae bioactive products. We expect that this review will encourage researchers to consider undervalued Apiaceae species as alternative sources of bioactive compounds and will give a contribute to the field by suggesting new research topics.

Human myiasis cases originating and reported in africa for the last two decades (1998-2018): A review

The article reviews literature on myiasis in Africa and cases that originated in Africa over the last two decades (1998-2018). The relevant literature was obtained by using several databases (Science-Direct, JSTOR, Google Scholar, Ebscohost and PubMed). We searched for the following words or their combination myiasis, maggots, fly species responsible for myiasis found in Africa, and the different types of myiasis. References in several articles provided links to other relevant works. Only papers written in English were reviewed. In total, we reviewed 51 articles which covered a total of 849 myiasis cases. The review encompasses geographical distribution of the disease, dipteran species responsible, predisposing factors, sex of the patient, type of myiasis and treatment. Myiasis is found in most parts of the African continent, however only 18 articles reported myiasis cases in Africa during the period under review. The rest of the articles report cases from the rest of the world but acquired by travellers when visiting Africa. Cordylobia anthropophaga (Blanchard) was responsible for 93.28% of all the reported cases in this review. The low number of articles on human myiasis reported in Africa may be due to underreporting by physicians or most cases are not diagnosed. Therefore, the actual prevalence of myiasis in Africa is currently unknown.

Insecticidal Activity of Hyoscyamus niger L. on Lucilia sericata Causing Myiasis

Background: Hyoscyamus niger L. (Solanaceae) generally known as henbane, is commonly distributed in Europe and Asia. In Turkey, henbane seeds have been used in folk medicine to remove worms from the eyes. The present study aimed to investigate the insecticidal activity of H. niger seeds. Methods: n-hexane, ethyl acetate, methanol and alkaloid extracts were prepared from the seeds of the plant and their insecticidal activities on Lucilia sericata larvae were evaluated. EC₅₀ and EC₉₀ values of the alkaloid extract were calculated and morphological abnormalities were investigated. Results: Alkaloid extract prepared from the seeds of this plant displayed significant insecticidal activity. EC₅₀ values of H. niger seeds alkaloid extract were found to be 8.04, 8.49, 7.96 μg/mL against first, second and third instar, respectively. It was determined that malformations of larvae included damaged larvae with small size, contraction and weak cuticle. Furthermore, HPLC analysis was performed on alkaloid extract of H. niger seeds and main components of the extract were determined. It was determined that alkaloid extract mainly contain hyoscyamine and scopolamine. Conclusions: These results confirm the folkloric usage of the plant and suggest that the alkaloid content of the plant could be responsible for the insecticidal activity.

Evaluation of Eugenol and (E)-Cinnamaldehyde Insecticidal Activity Against Larvae and Pupae of Musca domestica (Diptera: Muscidae)

Musca domestica L., 1758, is an important mechanical vector of several pathogens for humans and livestock, making it essential to study new alternatives of more efficient and safer control for this dipteran. This study evaluated the toxicity of the phenylpropanoids eugenol and (E)-cinnamaldehyde on its life stages. A contact test with 10 repetitions (n = 10) was performed for each substance concentration on each post-embryonic immature life stage. Both substances presented insecticidal activity on the immature life stages of the dipteran, and secondary effects on development caused by sublethal concentrations. Larvicidal activity was shown from the 1.25 mg/ml concentration by eugenol and from 2.5 mg/ml by (E)-cinnamaldehyde, and both substances had a 100% larval treatment efficacy (LTE) from the 5mg/ml concentration. For pupal treatment, (E)-cinnamaldehyde differed from the control from the 10 mg/ml concentration (P < 0.05), and both phenylpropanoids caused malformation in adults from 10 mg/ml. The highest pupal treatment efficacy (PTE) was obtained from the 30 mg/ml concentration, 67.2% for (E)-cinnamaldehyde, and 32% for eugenol. The products tested in this study showed high larvicidal potential, and both presented pupicidal effects and caused malformation in adults from treated pupae.

Efficacy and repellency of some essential oils and their blends against larval and adult house flies, Musca domestica L. (Diptera: Muscidae)

House flies are global pests and notoriously difficult to control. Essential oils of vetiver, cinnamon, and lavender and their blends were tested for toxic and repellent effects against larval and adult flies. All of the oils had moderate toxicity for eggs. Mortality of 2^nd instar larvae was 57-78% in dipping assays, 38-100% in contact assays, and 94-100% in treated media. Lavender was less effective (38% mortality) than the others (91-100%) in contact bioassays. Oil blends were not more effective against larvae than individual oils. Vetiver and cinnamon oils were strongly repellent (84 and 78%, respectively) for larvae in treated media. None of the oils were repellent for adult house flies in olfactometer assays, but testing of additional products demonstrated significant repellency for neem oil, p-menthane-3,8-diol (PMD), and vanillin. Contact/fumigant toxicity of vetiver, cinnamon, and lavender oils was 100%, significantly higher than mortality from sunflower oil (67%). Blends of oils were not more effective against adults than the individual oils, but blends diluted with sunflower oil were as effective as the individual oils. Essentials oils of vetiver and cinnamon may have potential for fly management in situations where conventional insecticides cannot be used.

Looking for the right mate-What we really know on the courtship and mating of Lucilia sericata (Meigen)?

Lucilia sericata is well known for causing myiasis in humans, livestock, pets and wildlife. It also vectors microbial pathogens, including paratuberculosis agents. This species can be exploited in maggot therapy to treat necrotic wounds, particularly those infected by multidrug-resistant pathogens. Despite its high medical and veterinary importance, our knowledge about its courtship and mating behavior is still limited. In this study, we quantified the courtship and mating behavior of L. sericata, shedding light on the potential impact of lateralization of selected behavioral traits during sexual interactions. When a male identified a female, he approached her with head pushing followed by foreleg tapping acts. Courtship lasted 7.65 ± 0.4 s. During copulation attempts, the male continued foreleg tapping acts on the female body, and tried to achieve genital contact. Copula lasted 14.88 ± 0.41 min, while male mating success was 85%. Several courtship and mating traits were found lateralized at population-level. Most of males approached the female with head pushing acts on her left side of the body. Both during courtship and copulation attempt phases, males mainly used the right foreleg to perform leg tapping acts on females. However, the impact of lateralized head pushing and foreleg tapping on the main behavioral parameters characterizing L. sericata courtship and mating was not significant, except for a higher number of foreleg tapping acts during copulation attempts displayed by right-biased males over left-biased ones. Overall, these results contribute to improve our basic knowledge on the reproductive behavior of L. sericata. Besides, selected behavioral parameters characterized here can be exploited as benchmarks to monitor mate quality during mass-rearing, as well as to select males with boosted mating competitiveness, helping to improve the success of SIT programs and behavior-based control tools.

Insecticide activity of Curcuma longa (leaves) essential oil and its major compound α-phellandrene against Lucilia cuprina larvae (Diptera: Calliphoridae): Histological and ultrastructural biomarkers assessment

Lucilia cuprina, known as the Australian blowfly, is of high medico-sanitary and veterinary importance due to its ability to induce myiasis. Synthetic products are the most frequent form of fly control, but their indiscriminate use has selected for resistant populations and accounted for high levels of residues in animal products. This study aimed to assess the effect of essential oil from leaves of Curcuma longa (CLLEO), and its major compound α-phellandrene against L. cuprina L3. An additional goal was to determine the morphological alterations in target organs/tissues through ultrastructural assessment (SEM) and light microscopy, as well as macroscopic damage to cuticle induced by CLLEO. Groups of 20 L3 were placed on filter paper impregnated with increasing concentrations of CLLEO (0.15 to 2.86 μL/cm²) and α-phellandrene (0.29 to 1.47 μL/cm²). Efficacy was determined by quantifying L3 mortality 6, 24 and 48 h after contact with CLLEO and by measuring the structural damage to L3. CLLEO and α-phellandrene inhibited adult emergence by 96.22 and 100%, respectively. Macroscopic cuticle damage, appeared as diffuse pigment and darkening of larval body, was caused by both extracts. The SEM revealed dryness on the cuticle surface, distortion of the sensorial structures and general degeneration in treated L3. Furthermore, alterations in target organs (digestive tract, fat body and brain) were noticed and shall be used as biomarkers in future attempts to elucidate the mechanism of action of these compounds. The vacuolar degeneration and pyknotic profiles observed in the brain tissue of treated larvae with both extracts and the decreased motility within <6 h after treatment leads us to suggest a neurotoxic activity of the products. This work demonstrates the potential use of CLLEO and α-phellandrene as bioinsecticides to be used against L. cuprina, representing an ecofriendly alternative for myiasis control in humans and animals.

Potential of essential oils to prevent fly strike and their effects on the longevity of adult Lucilia sericata

Lucilia sericata is a facultative ectoparasite causing fly strike or myiasis in warm-blooded vertebrates. It is controlled by traps or insecticides, but both have drawbacks and alternative ways of control are urgently needed. Essential oils (EOs) of vetiver (Chrysopogon zizanioides), cinnamon (Cinnamomum zeylanicum), and lavender (Lavandula angustifolia) and their blends (OBs); OB1 (2 ml of each EO plus 4 ml of sunflower oil as a carrier) and OB2 (2 ml of each EO) were tested. Oils were tested at 5% for deterrence assays, and a dose response assay 0.01-0.6%, was conducted to determine forced-contact toxicity. We evaluated the efficacy of oils as oviposition deterrents, repellents/attractants, and their effects on mortality and longevity of adult L. sericata. Our data indicated that 0.2% EOs killed all flies by 5 min post-treatment and that vetiver oil greatly deterred flies from the oviposition medium and reduced adult longevity. Sunflower oil repelled all flies from ovipositing and greatly reduced the lifespan of treated adults. The blend of the four oils (OB1) had the greatest repellent effect on the flies. EOs have insecticidal, repellent, and oviposition-deterrent activities against L. sericata that could be used for suppression of blow fly populations.

In vitro Safety and Efficacy of Lavender Essential Oil (Lamiales: Lamiaceae) as an Insecticide Against Houseflies (Diptera: Muscidae) and Blowflies (Diptera: Calliphoridae)

Essential oils are considered an alternative for replacement of conventional insecticides that have provoked an increasing number of resistant species and damages to health. The objective of this work was to investigate the insecticidal activity of Lavandula dentata L. (Lamiales: Lamiaceae) oil against the species Musca domestica L. (Diptera: Muscidae) and Chrysomya albiceps Wiedemann (Diptera: Calliphoridae). Extraction of the essential oil from the aerial parts of the plant was carried out using hydro-distillation. Its principal compounds (1,8-cineol, camphor, and linalool oxide) were identified. Insecticidal activity was determined by evaluating adulticidal effect using topical application methods and exposure to impregnated paper; larvicidal effect was determined using immersion method. The essential oil presented toxicity in M. domestica and C. albiceps adults; the lethal concentration values (LC50) in the superficial application method were respectively 3.13 ± 0.64 and 1.39 ± 0.19% live weight (l/v). Toxicity was also found in the oil impregnated paper exposure test; the LC50 results for M. domestica and C. albiceps were respectively 4.15 ± 0.64 and 5.14 ± 0.81%. Larvicidal effect was observed on third stage M. domestica larvae when exposed to an oil concentration of 2.5% (m/v). In addition, the oil was evaluated for cytotoxicity, mutagenicity, and genotoxicity in human cells, and the in vitro safety of this oil in human cells was verified. Thus, L. dentata oil presented insecticidal activity in M. domestica and C. albiceps and can be used as an alternative for control of these dipterans.

High innate attractiveness to black targets in the blue blowfly, Calliphora vomitoria (L.) (Diptera: Calliphoridae)

Calliphora vomitoria is a myiasis-causing fly in many animal species including humans. The control of blowflies is still anchored on the use of chemicals. However, mass trapping and lure-and-kill techniques represent a promising alternative to pesticides. Visual and olfactory cues are the main stimuli routing the fly's landing behavior. Notably, color attractiveness has been barely explored in flies of medical and veterinary importance, with special reference to blowflies. In this study, we investigated the innate color preferences in C. vomitoria adults, testing binary combinations of painted targets under laboratory conditions. The identity of tested species C. vomitoria was confirmed by DNA sequencing (18S and cox1 genes). C. vomitoria flies showed a significant preference for black colored targets in all tested binary color combinations, after 5, 15, 30 and 60 min of exposure. Black targets were significantly preferred over blue, red, yellow and white ones. Spectral characteristics of all tested color combinations were quantified and the innate attraction of blowflies towards black targets was discussed in relation to their behavioral ecology. To the best of our knowledge, this is the first report on innate color preferences in the Calliphora genus. Our findings can be useful to develop new, cheap and reliable monitoring traps as well as "lure and kill" tools to control blowfly pests.

Efficacy of some essential oils on Cephalopina titillator with special concern to nasal myiasis prevalence among camels and its consequent histopathological changes

Nasopharyngeal myiasis is an important high incidence disease among camels in the Middle East and North of Africa caused by Cephalopina titillator (C. titillator) that results in sever economic losses in many camel breeding areas around the world. The current study was conducted to evaluate the efficacy of three essential oils; camphor, ginger and cinnamon oils and their histopathological effects on the 3rd larval instar of C. titillator, with special regard to the prevalence percentage of C. titillator infestation in slaughtered camels at Egyptian abattoirs in addition to investigate histopathological alterations of the infested animal's tissue. This study fulfilled that the prevalence of C. titillator infestation was 35.2% among slaughtered camels during summer season. The three tested essential oils were caused a significant mortality of C. tittilator; however, camphor oil was exhibited greater and quicker insecticidal effect than ginger and cinnamon oils at the same concentration in terms of mortality of the 3rd instar C. tittilator larvae. There was a concentration-dependent effect on the larvae among the tested essential oils. The tested essential oils were caused remarkable histopathological alterations on the treated larval cuticle. The main salient lesions of the examined infested camel's tissue were necrotic and inflammatory alterations associated with cystic dilation of submucosal glands.

Toxicity and growth inhibition potential of vetiver, cinnamon, and lavender essential oils and their blends against larvae of the sheep blowfly, Lucilia sericata

BACKGROUND

Myiasis induced by the sheep blowfly, Lucilia sericata, represents a public health problem widely distributed throughout the world. L. sericata larval stages feed on both humans and animals. L. sericata adults and larvae can play a role in spreading agents of mycobacterial infections.

OBJECTIVES

It is critical to establish new and safe alternative methods of controlling L. sericata.

METHODS

The insecticidal effectiveness and growth inhibition potential of three commercially available essential oils (EOs), vetiver (Chrysopogon zizanioides), cinnamon (Cinnamomum zeylanicum), and lavender (Lavandula angustifolia), as well as their blends, were tested against the second (L2) and third (L3) larval stages of L. sericata. Sunflower (Helianthus annuus) oil was used as a carrier and tested on L2 and L3 larvae. To the best of our knowledge, all applied essential oils, except lavender, and oil blends were tested against L. sericata for the first time.

RESULTS

All applied oils did not repel L2 from the treated liver but adversely affected their development. Contact treatments on L. sericata L3 indicated that vetiver and cinnamon oils significantly affected treated larvae. Total mortality rates were 93.33 and 95.56%, respectively. Furthermore, oil blends tested through contact assays killed larvae when used at higher concentrations; adult emergence was eliminated post-treatment with doses >30% for oil blend 1 and >10% for oil blend 2.

CONCLUSION

Overall, cinnamon and vetiver oils (5%) were selected as reliable and cheap biopesticides for controlling larvae of L. sericata. The tested oils are inexpensive and represent new promising botanical insecticides in the fight against blowflies causing myiasis.

Immunological evaluation of some antigens of Lucilia sericata larvae

The present study aimed to select an antigen of Lucilia sericata larvae showing both high antigenicity and cross-reactive binding abilities with other related antigens of L. sericata larvae for obtaining a promising candidate vaccine antigen. The ELISA results primary concluded that among the excretory secretory (ES) and midgut (MG) antigens of the different larval instars of L. sericata, MGL2 could be characterized as antigen which was able to reflect the highest level of antigenicity and cross-reactivity with the other tested L. sericata antigens. The results were extended to spot the light on the relation between different protein bands in MGL2 and rabbit hyper- immune sera (HIS) raised against the other tested antigens using SDS-PAGE and Western blot technique. Analysis by SDS-PAGE of ES and MG antigens of the different larval instars of L. sericata revealed common protein bands at molecular weights of about 10, 12, 16, 20, 28, 33 and 46 kDa. Western blotting of MGL2 antigen transferred to nitrocellulose sheet revealed reaction by MGL2 HIS to five polypeptide bands; 20, 28, 33, 46 and 63 kDa. Three bands of 28, 33 and 63 kDa were the most prominent bands detected whereas; there was a weak reaction with bands of 20 and 46 kDa. But what was apparent in Western blot was a strong reaction of all tested HIS with a polypeptide band of 63 kDa. This band might be considered to be the main cause of cross reactive binding ability of MGL2 antigen that had been recorded previously in ELISA technique.

Larvicidal activity of camphor and lavender oils against sheep blowfly, Luciliasericata (Diptera: Calliphoridae)

In this study, the essential oils of camphor and lavender were tested in vitro against the third instar larvae of Lucilia sericata for the first time, following dipping toxicity technique. The toxicity results revealed that L. sericata larvae were susceptible to the applied essential oils. Lavender oil was more effective than camphor in killing of L. sericata larvae. With 32 % concentration, the mortality percentages of larvae were 100 and 93.3 %, respectively. Light and scanning electron microscopic examinations were done to determine the cuticular changes of L. sericata larvae following exposure to the applied essential oils. Larvae showed cuticular swelling and distortion after oil treatment, but its level was greater with lavender oil. The current study suggested that an alternative, effective and natural product can be developed as larvicides against L. sericata using camphor and lavender oils.

Erratum to: the acaricidal efficacy of peracetic acid and deltamethrin against the fowl tick, Argas persicus, infesting laying hens

The fowl tick, Argas persicus (Oken), is of veterinary importance as a parasite of poultry and wild birds. The antitick efficacy, in vitro and in vivo, of peracetic acid (PAA) and deltamethrin (DMT) was tested separately against A. persicus through the dipping technique. PAA (0.5%) was highly efficient against soft tick larvae (A. persicus), resulting in 100 % mortality after 2 min. The lethal concentrations LC₅₀ and LC₉₅ were 0.310 and 0.503 %, respectively. The lethal time values LT₅₀ and LT₉₅ were 5.34 and 40.00 min, respectively, after treatment with PAA (0.25%). Two minutes after exposure to DMT, LC₅₀ and LC₉₅ values were 0.0033 and 0.0052% (33.204 and 51.527 mg/L), respectively. The LT₅₀ and LT₉₅ values were 27.03 and 305.46 min, respectively, after treatment with 0.0025% DMT (25 mg/L). After dipping in PAA (0.5%), the chickens did not show respiratory signs or inflammation on the eyes and/or skin. By contrast, temporary coughing, sneezing, and ocular inflammations without dermatitis were observed in chickens dipped in DMT (0.005 % or 50 mg /L). Seven days posttreatment (PT), the reduction in the percentages of A. persicus infesting laying hens were 99.15 and 63.42% after dipping in PAA and DMT, respectively. However, complete elimination of the number of ticks occurred after 28 days PT with DMT. PAA inhibits molting effectively (28%) when compared with that of DMT (52%). Results indicated that PAA is a more potent and promising acaricide against A. persicus (in vitro and in vivo) than DMT.

Isolation of seselin from Clausena anisata (Rutaceae) leaves and its effects on the feeding and development of Lucilia cuprina larvae may explain its use in ethnoveterinary medicine

ETHNOPHARMACOLOGICAL RELEVANCE

The leaves of Clausena anisata are used traditionally to expel maggots from wounds of animals in Zimbabwe. We have previously proved in the laboratory that the plant certainly affects the behaviour and growth of blowfly larvae. The objective of this study was to isolate and identify the active compounds responsible for this activity.

MATERIALS AND METHODS

The acetone extract of Clausena anisata leaf powder was separated by solvent-solvent partition into five fractions. The n-hexane fraction was the most active in the larvicidal assay and therefore subjected to open column chromatography on silica gel.

RESULTS

The isolated compound was identified by nuclear magnetic resonance (NMR) and mass spectroscopy (MS) as the pyranocoumarin, seselin, chemically known as 2',2'-dimethylpyranocoumarin. It inhibited feed intake in the first and second instars of blowfly larvae at the minimum concentration tested of 1 ppm resulting in significant lower mass pupae (13.5±0.5 mg and 22.4±0.4 mg for the first and second instar larvae respectively) compared to the solvent control group (26.19±0.8 mg) (p<0.05).

CONCLUSIONS

This is the first report of the isolation of seselin from the leaves of Clausena anisata and the first report of the compound having an effect against blowfly larvae.

In vitro control of the camel nasal botfly, Cephalopina titillator, with doramectin, lavender, camphor, and onion oils

Camels are very important livestock particularly in arid and semiarid lands. The oestrid fly, Cephalopina titillator (Clark), causes nasopharyngeal myiasis in camels, and it is widely distributed in many camel breeding areas triggering health hazards and severe economic losses in camels. The prevalence of infestation of camels (slaughtered at Tokh's slaughterhouse, Qalyubia Governorate, Egypt, during the period from September 2011 to March 2012) was 41.67 % (100 out of 240). Most infested camels developed clinical signs of nasal discharge, restlessness, loss of appetite, difficulty in breathing, frequent sneezing, and snoring. Postmortem examination of infested camels explained that breathing of the animal is greatly impaired because of blockage of the nasopharynx by larvae and/or mucofibrinous secretions. The larval count per camel ranged from 1 to 250 (mean 28.45 ± 6.48). In vitro larval immersion tests were carried out to determine the efficacy of doramectin (0.003 %) as well as some essential oils (50 % each) such as lavender, camphor, and onion oils against the second and third larval stages (L2 and L3) of C. titillator. Another trial had been done for imitating what could happen if the area around camels were treated with an insecticide or an insect repellent. All treated L2 died 18 h posttreatment (PT) with both doramectin and lavender, and 100 % mortality was reached for L3 after 24 and 30 h PT with lavender and doramectin, respectively. Doramectin and lavender induced the highest response against C. titillator as their lethal time (LT50) values after treatment of L2 were 3.40 and 3.60 h, respectively, and those of L3 were 4.99 and 5.53 h, respectively. Against both L2 and L3 of C. titillator and based on LT50 values of onion oil and those of other applied materials, doramectin and lavender oil were four times more effective than onion oil, and camphor oil was two times more effective than onion oil. Based on LT50 values of essential oils and those of doramectin, as a reference substance, the relative speed of efficacy indicated that camphor and onion oils were, respectively, two and four times less effective than doramectin and lavender. With regard to fumigant technique, neither the insecticide, New Pyrosol, nor the insect repellent, Keto, was effective in controlling C. titillator larvae. Our results indicated that doramectin and lavender could be selected as drugs of choice for controlling C. titillator, but it is not permitted to use doramectin on dairy animals during lactation. Lavender (50 %) has a great potential to be developed as a novel larvicide and could be used as nasal drench against nasal botfly which will reflect on camel production and the national economy.

The acaricidal efficacy of aqueous neem extract and ivermectin against Sarcoptes scabiei var. cuniculi in experimentally infested rabbits

Sarcoptes scabiei var. cuniculi is one of the most important veterinary ectoparasites in rabbits and results in considerable loss of weight, productivity, and wool quality. The acaricidal activity of aqueous leaf extract of neem (CAN) and ivermectin (IVR) were evaluated in vitro and in vivo against S. scabiei var. cuniculi. Rabbits were classified into four groups (ten rabbits each). The first group (group 1) was designated as the negative control group. Each rabbit of the other groups was experimentally infested with 50 mites. One month post-infestation, the second group (group 2) was not treated and taken into account as the positive control group. The third group (group 3) was subcutaneously injected with 1 % IVR (200 μg/kg body weight, three times within a week interval). The fourth group (group 4) was treated topically with CAN (25 %) every 3 days for three consecutive weeks. Index scoring of lesions was described weekly. The number of live mites (larvae, nymphs, and adults) on each rabbit was counted on the 14th, 28th, and 42th day post-treatment (PT). Blood samples were taken 28 and 42 days PT for estimation of some chemical parameters. The body weight and cumulative body weight gain were recoded 14, 28, and 42 days PT. CAN (40 %) was highly efficacious against larvae of S. scabiei var. cuniculi as 100 % mortality was reached 24 h PT. On the other hand, all treated mites with CAN (20 %) and IVR died 48 h PT. The lethal values of CAN (LC50, LC90, LC95, and LC99) were 7.496, 14.67, 17.75, and 25.37 %, respectively, 48 h PT. Lesion scoring in groups 3 and 4 were significantly decreased (P ≤ 0.05), reaching 0.20 and 0.40, respectively, when compared with that of group 2 (4.00), 42 days PT. Twenty-eight days PT, the reduction percentages of mites infesting rabbits were 93.38 and 93.09 % for IVR and CAN, respectively. However, complete mite reduction was reached 42 days PT. Rabbits treated with CAN did not show signs of restlessness or irritation, respiratory signs, or inflammation on the eye and/or skin at the time of application or afterwards. Regarding biochemical analysis, the levels of aspartate aminotransferase, alanine aminotransferase, creatinine, and total cholesterol in rabbits treated with CAN were decreased significantly (P ≤ 0.05) than those of rabbits of the positive control group and those treated with IVR. On the other hand, the levels of total protein, albumin, and globulin of rabbits in group 4 were significantly (P ≤ 0.05) increased when compared with the corresponding values of groups 2 and 3. The body weight and cumulative body weight gain of rabbits treated with CAN were significantly increased (P ≤ 0.05) when compared with such values of groups 2 and 3, 28 and 42 days PT. The present data indicated that CAN had in vitro and in vivo acaricidal efficiency similar to that of IVR and improved the performance of rabbits without inducing adverse effects on treated rabbits; consequently, CAN could be suitable as a promising alternative acaricide for veterinary use.

Extracts of four plant species used traditionally to treat myiasis influence pupation rate, pupal mass and adult blowfly emergence of Lucilia cuprina and Chrysomya marginalis (Diptera: Calliphoridae)

ETHNOPHARMACOLOGICAL RELEVANCE

Aloe zebrina, Clausena anisata, Erythrina lysistemon and Spirostachys africana are used traditionally in southern Africa to combat and/or treat myiasis, the infestation of the skin of mammals by larvae of a variety of fly species belonging to the arthropod order Diptera.The objective of the study was to establish the in vitro effect of extracts of these plant species on blowfly larvae to ascertain the potential use of these extracts and validate the traditional use.

MATERIALS AND METHODS

Chrysomya marginalis and Lucilia cuprina larvae cultured in the laboratory under controlled conditions were exposed to meat treated with acetone and aqueous extracts of four different plant species. In addition to solvent controls, the effects of the plant extracts were tested at concentrations of 10, 25, 50, 75, 100 and 150 mg/ml. Larval behaviour, larval development and emergence of adult flies were assessed after exposing the larvae to the treated meat. Ivermectin was used as a positive control while acetone and water served as solvent controls. Cytotoxicity of the extracts was determined using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide] assay against C3A human liver cells, bovine dermis cells and Vero African green monkey kidney cells.

RESULTS

An increase in the concentration of the acetone plant extracts resulted in a decrease in the ingestion of meat by larvae, pupal mass and adult emergence rates. The R(2) values for the correlation between dose and pupal mass was 0.92, 0.74 and 0.65 for A. zebrina, C. anisata, and E. lysistemon respectively. For C. anisata and S. africana extracts the increase in the concentration was also associated with the emerging adult flies being smaller. C. anisata was the most toxic plant extract, with an average IC(50) of 39 μg/ml, while E. lysistemon was the least toxic. Vero cells were the most susceptible cell type, with an average IC(50) of less than 100 μg/ml, while the human liver cells were the most resistant to the effect of the plant extracts.

CONCLUSIONS

The results suggest that the plants may contain compounds that interfere with larval feeding and the neuroendocrine control mechanisms in the blowfly. It appears that some of these plant species have the potential to deliver a product that can be used to control myiasis.

Ovine cutaneous myiasis: effects on production and control

Ovine cutaneous myiasis ('fly strike') remains a major sheep health problem in many areas of the world. Myiasis risk is the result of a complex interaction of factors, such as fly and host abundance, host susceptibility, climate and, critically, husbandry and management strategies, all of which change seasonally in space and time. Given the complexity of the interacting factors, changes in myiasis incidence are hard to predict, as accordingly are the optimal husbandry responses required to manage the problem. Here the important risk factors are briefly reviewed and the future changes in myiasis incidence under conditions of anticipated climate change are considered. It is concluded that future work should focus in particular on evaluating the optimum use of integrated management, such as the combination of insecticide and trap use, in different environments under a range of farming regimes.

Control of the myiasis-producing fly, Lucilia sericata, with Egyptian essential oils

BACKGROUND

Myiasis caused by Lucilia sericata (Diptera: Calliphoridae) is widely distributed throughout the world and affects both humans and animals. In addition, L. sericata larvae and adults may play a role in spreading causal agents of mycobacterial infections. Therefore, it is important to establish new and safe alternative methods of controlling this blowfly.

METHODS

The insecticidal effectiveness of four commercially available essential oils [lettuce (Lactuca sativa), chamomile (Matricaria chamomilla), anise (Pimpinella anisum), rosemary (Rosmarinus officinalis)] against third larval instars of L. sericata was evaluated. The effects of sublethal concentrations of these oils on pupation rates, adult emergences, sex ratios, and morphological anomalies were also determined.

RESULTS

The oils were highly toxic to L. sericata larvae, with median lethal concentrations (LC(50) ) of 0.57%, 0.85%, 2.74%, and 6.77% for lettuce, chamomile, anise, and rosemary oils, respectively. Pupation rates were markedly decreased after treatment with 8% lettuce oil, and adult emergence was suppressed by 2% lettuce and chamomile oils. Morphological abnormalities were recorded after treatment with all tested oils, and lettuce was the major cause of deformation. There was a predominance of males over females (4 : 1) after treatment with lower concentrations of chamomile and rosemary; such a skew toward males would lead to a population decline.

CONCLUSIONS

The four tested oils are inexpensive and may represent new botanical insecticides for controlling blowflies.

Lousicidal, ovicidal and repellent efficacy of some essential oils against lice and flies infesting water buffaloes in Egypt

The lousicidal and repellent effects of five essential oils were investigated for the first time against the buffalo louse, Haematopinus tuberculatus, and flies infesting water buffaloes in Qalyubia Governorate, Egypt. For the in vitro studies, filter paper contact bioassays were used to test the oils and their lethal activities were compared with that of d-phenothrin. Four minutes post-treatment, the median lethal concentration, LC50, values were 2.74, 7.28, 12.35, 18.67 and 22.79% for camphor (Cinnamomum camphora), onion (Allium cepa), peppermint (Mentha piperita), chamomile (Matricaria chamomilla) and rosemary oils (Rosmarinus officinalis), respectively, whereas for d-phenothrin, it was 1.17%. The lethal time (50) (LT50) values were 0.89, 2.75, 15.39, 21.32, 11.60 and 1.94 min after treatment with 7.5% camphor, onion, peppermint, chamomile, rosemary and d-phenothrin, respectively. All the materials used except rosemary, which was not applied, were ovicidal to the eggs of H. tuberculatus. Despite the results of the in vitro assays, the in vivo treatments revealed that the pediculicidal activity was more pronounced with oils. All treated lice were killed after 0.5-2 min, whereas with d-phenothrin, 100% mortality was reached only after 120 min. The number of lice infesting buffaloes was significantly reduced 3, 6, 4, 6 and 9 days after treatment with camphor, peppermint, chamomile, onion, and d-phenothrin, respectively. Moreover, the oils and d-phenothrin significantly repelled flies, Musca domestica, Stomoxys calcitrans, Haematobia irritans and Hippobosca equina, for 6 and 3 days post-treatment, respectively. No adverse effects were noted on either animals or pour-on operators after exposure to the applied materials. Consequently, some Egyptian essential oils show potential for the development of new, speedy and safe lousicides and insect repellents for controlling lice and flies which infest water buffaloes.