Adulticidal Activity Research Articles

Suppressive Impact of 6-Benzyladenine, A Plant Growth Regulator, on the Adult Performance and Reproductive Potential of Galleria mellonella L. (Lepidoptera: Pyralidae)

The greater wax moth Galleria mellonella is responsible for serious economic losses to bee keepers in developing countries. Larvae feed on the wax comb in weak colonies or during the storage of wax combs in winter. The objective of the current study was to assess the effect of the Cytokinin plant growth regulator, Benzyladenine (6-BA), on the most important parameters of adult performance and reproductive potential of G. mellonella. The 3rd instar larvae were force-fed on an artificial diet supplemented with six concentrations, viz., 100, 10.0, 1.0, 0.1, 0.01 & 0.001ppm of 6-BA. No adult moths could metamorphose at the higher three concentrations because of larval and pupal deaths. The most important results could be summarized as follows. The adult emergence was blocked by 6-BA, in a dose-dependent course. Also, the tested compound displayed strong adulticidal activity, since adult mortality increased in a dose-dependent course. The total adult longevity of moths was significantly prolonged.All longevity compartments were remarkably prolonged. On the other hand, 6-BA failed to affect adult morphogenesis. The oviposition efficiency was deleteriously prohibited. Also, 6-BA exhibited a tremendous inhibitory effect on the female fecundity and reducing effect onfertility. The embryonic development in eggs laid by treated adult females was severely retarded, since the incubation period of these eggs was remarkably prolonged.

A review on the bioactivities of Justicia gendarussa

Willow-leaved justicia (Justicia gendarussa) can be found wild or cultivated in Indonesia, India, China, Malaysia, Sri Lanka, the Philippines, and Bangladesh. In Indonesia, willow-leaved justicia leaveis widely used in traditional medicines by Indonesian local inhabitants. The present work provides a review addressing bioactivities of willow-leaved justicia. The observed bioactivities of willow-leaved justicia include antioxidant, hepatoprotective, anti-inflammation, anti-microbial (anti-fungal, anti-bacterial, anti-viral), anthelmintic, anti-cancer, anti-sickling, larvicidal and adulticidal activities.

Larvicidal, adulticidal and repellent activities against Aedes aegypti L. of two commonly used spices, Origanum vulgare L. and Thymus vulgaris L.

The high incidence of dengue, chikungunya, and Zika indicates the importance of controlling the vector of these arboviruses in the tropical and subtropical regions of the world. However, vector control is hindered by pesticide resistance and the limited success of biocontrol programs against Aedes mosquitoes. Despite these difficulties, the study of common plant species, including those with commercial value, can offer effective and ecological tools in the fight against mosquitoes. In the present study, the essential oils obtained from the aerial parts of Origanum vulgare L. and Thymus vulgaris L. were analyzed by GC–MS and evaluated for their larvicidal, adulticidal and repellent activities against Aedes aegypti L. The main constituents of the O. vulgare essential oil were terpinen-4-ol (17.4%), carvacrol (16.0%) and thymol (10.4%), and the main constituents of the T. vulgaris essential oil were thymol (40.0%), p-cymene (19.3%) and γ-terpinene (17.3%). Both essential oils were toxic to Ae. aegypti larvae with LC50 values of 37.5 μg/mL for O. vulgare and 38.9 μg/mL for T. vulgaris. For adult mosquitoes, the LC50 values were 14.3 and 11.7 μg/mL, respectively. The essential oils of O. vulgare and T. vulgaris showed a significant repellency effect, with values ranging from 8.9% to 37.8% and 4.4% to 68.9%, respectively. In addition, morphological differences between larvae treated with the EOs and the control group were evidenced by optical microscopy. Thus, the results suggest that the essential oils of O. vulgare and T. vulgaris have potential use as an ecofriendly source to develop new insecticides for the control of Ae. aegypti.

Insecticidal, antibacterial and dye adsorbent properties of Sargassum muticum decorated nano-silver particles

Marine algae contain many bioactive constituents. In the current research, the brown seaweed Sargassum muticum was collected from Red Sea and its extract used as a capping agent for the formulation of biocompatible stable silver nanoparticles (AgNPs). The seaweed-fabricated AgNPs were studied through UV–vis, TEM, XRD, EDX, FTIR and Zeta potential analyses. The chemical constituents of S. muticum extract were evaluated by RP-HPLC and 1H NMR. Both seaweed extract and AgNPs had mosquito larvicidal and adulticidal activities. The seaweed-fabricated AgNPs induced high larval mortality against mosquitoes from both Indian and Saudi Arabian strains when compared to the seaweed extract. The LC50 values of AgNPs against the Indian strains of Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi were 43.9, 35.9 and 27.0 μg/ml, respectively; those against the Saudi Arabian strains of Ae. aegypti and Cx. pipiens were 110.4 and 126.2 μg/ml, respectively. In adulticidal experiments, the LC50 values of S. muticum-fabricated AgNPs against Indian strains of Cx. quinquefasciatus, Ae. aegypti and An. stephensi were 42.3, 34.3 and 29.7 µg/ml, respectively, whereas those against the Saudi Arabian strains of Ae. aegypti and Cx. pipiens were 86.4 and 120.0 µg/ml, respectively. Minimal doses of seaweed-fabricated AgNPs were highly effective in inhibiting the growth of Bacillus subtilis (11.25 mm inhibition zone), Escherichia coli (13.35 mm), Klebsiella pneumoniae (14.24 mm) and Salmonella typhi (12.23 mm). Additionally, the seaweed extract was highly efficient to adsorb methylene blue (MB) and methyl orange (MO) dyes. In conclusion, the S. muticum extract revealed to be an effective capping agent to fabricate AgNPs to be industrially used for the control of deadly mosquito vectors and as an antimicrobial and dye adsorbent agent.

Comparing the efficacy of nutmeg essential oil and a chemical pesticide against Musca domestica and Chrysomya albiceps for selecting a new insecticide agent against synantropic vectors

The insecticidal activity of Myristica fragrans (Houtt) essential seed oil, (Nutmeg) was evaluated against Musca domestica (Linnaeus) and Chrysomya albiceps (Wiedemann); both important infectious pathogenic disease vectors. The oil was extracted by distillation, and 21 components were identified during chemical analysis; principally β-pinene (26%), α-pinene (10.5%), Sabinene (9.1%) and γ-terpinen (8.5%). Insecticidal properties were identified through larvicide and adulticide tests. Using the immersion method, the oil at 5% was found to be very effective (90 ± 1%) against M. domestica larvae. The results for adulticide activity varied by fly species, dosage, time, and method of exposure. Topical application (on the insect thorax) was more toxic to C. albiceps, where the lethal concentration at 50% (LC50) was 2.02 ± 0.56, and 8.57 ± 2.41 for the common flies. When the insects were exposed to oil impregnated paper, the results were similar for M. domestica and C. albiceps adults with respective LC50 values of 2.74 ± 0.24, and 3.65 ± 0.48. Thus, the results demonstrated that M. fragrans oil presents insecticidal activity and can be used for control of Musca domestica and Chrysomya albiceps.

Evaluation of adulticidal activities of some selected plant species against Anopheles gambiae

Plants extracts have been used as alternative sources of mosquito control since the ancient time prior to the development of synthetic pesticides due to the presence of repellent properties against insects. Anopheles gambiae mosquito is the vectors of Malaria disease in Tropical and Subtropical Africa, and the present practice of using synthetic pesticides to control the vector have results in the development of resistance by the mosquitoes and the pesticides causes environmental pollution and damages the ecosystem. The aim of this study was to evaluate the adulticidal activities of some plant species against Anopheles gambiae. The results of the Phytochemical analysis showed that, Anthroquinones, Soluble Steroids and Tannis are present in Jatropha curcas while Adansonia digitata possesses Saponins, Flavonoids, Anthroquinones and Tannins. C. citrates was reported to be possessing Flavonoids, Soluble starch and Tannins and was mostly reported plants to be possessing higher insecticidal properties against mosquitoes. Zingiber officinale was found possessing Saponins, Alkaloids and Tannins and finally, the Lausonia inermis possessng only Anthroquinones and Alkaloids. The results of the adulticidal activities shows the Jatropha curcas causes the highest mortality at 87% of An. gambiae among the plant extracts tested in this study at the highest concentrations of 20mg/ml at the lowest LC50 value of 4.217mg/ml and LC90 of 15.76mg/ml respectively and the plant with the lowest was Z. officinale with the highest mortality of 21% and the highest LC50 of 6710.051mg/ml respectively. We conclude that, these plants extracts can be used as alternative bioinsecticides for An. gambiae, a Malaria vector control to reduce the Malaria burden in the study area that annually causes significant death and overwhelm the health facilities.

Improved adulticidal activity against Aedes aegypti (L.) and Aedes albopictus (Skuse) from synergy between Cinnamomum spp. essential oils

Improved natural adulticidal agents against mosquito vectors are in urgent need, and essential oils from Cinnamomum plants can assume this role quite readily. Cinnamomum verum, C. cassia, and C. loureiroi essential oils (EOs) were extracted from the barks and evaluated for their chemical composition by GC–MS. The major constituent of the three EOs was cinnamaldehyde. WHO susceptibility tests on individual and combined EOs as well as cinnamaldehyde were conducted against female adults of Aedes aegypti and Aedes albopictus. All EO combinations exhibited a synergistic effect, manifesting a higher toxicity, with a synergistic value ranging from 2.9 to 6.7. Their increasing mortality value was improved between 16.0 to 41.7%. The highest synergistic effect was achieved by an EO combination of 0.5% C. cassia + 0.5% C. loureiroi, while the highest insecticidal activity was achieved by 2.5% C. verum + 2.5% C. cassia and 1% cinnamaldehyde, with a knockdown and mortality rate of 100% and a KT50 between 0.7 and 2.1 min. This combination was more toxic to both mosquito species than 1% w/v cypermethrin. These findings demonstrate that cinnamaldehyde and synergistic combinations of C. verum + C. cassia EOs and C. cassia + C. loureiroi EOs have a high insecticidal efficacy against Aedes populations.

Volatiles from Marina neglecta: Biocide effect on insect vectors of tropical diseases in Southern Mexico

• Essential oils of M. neglecta contained β-pinene, β-caryophyllene and germacrene D. • Essential oils and main volatiles produced a biocide effect in four insect vectors. • β-Pinene produced significant and fast mortality in life stages of triatomines. • Germacrene D produced significant and fast mortality in life stages of mosquitoes. Preventive measures based in the control of insect vectors are considered as the best choice to decrease the incidence of insect-borne diseases. Herein we report on the volatile content of the leaf essential oils from Marina neglecta , a medicinal plant distributed in the tropical regions of southern Mexico. In order to investigate the chemical variation of the essential oils, a volatile screening was performed during the four seasons of the years 2016–2019. Simultaneously, their biological activity was tested on distinct life stages of Meccus pallidipennis , M. bassolsae , Aedes aegypti and A. albopictus . Essential oils were mainly constituted of β-pinene (>30%) β-caryophyllene (>25%) and germacrene D (>13%). Dorsal-abdomen application of essential oils on triatomines, revealed an efficient LC 50 for nymphs of the stages I to III (4 µg/insect), nymphs of the stages IV to V (5–6 µg/insect), and adults (7–8 µg/insect). The LT 50 for the stages I to III was between 6 and 8 h, whereas that for the stages IV to V and adults oscillated between 12 and 16 h and 22 to 26 h, respectively. Fumigation experiments performed on nymph V, demonstrated that 300 µg L −1 air produced 100% mortality after 72 h post-treatment. Among tested volatiles, β-pinene and β-caryophyllene produced a comparable mortality rate ( p < 0.01) than that of essential oils in the stages assayed. Essential oils showed strong larvicidal (LC 50 , 24–36 µg mL −1 ) and adulticidal (35–48 µg mL −1 ) activities in mosquito species with an LT 50 of 4.5 h and 25–35 min, respectively. The evaluation of β-pinene produced a significant mortality rate ( p < 0.01) in larvae whereas germacrene D was the most effective volatile ( p < 0.01) against adults of both mosquito species. According to our results, β-pinene was the most effective volatile against the four insect species evaluated and its effect was comparable to that of the essential oil.

Insecticidal Activity and Free Radical Scavenging Properties of Isolated Phytoconstituents from the Saudi Plant Nuxia oppositifolia (Hochst.).

Chromatographic purification of the alcoholic extract from the aerial parts of the Saudi plant Nuxia oppositifolia (Hochst.), Benth., resulted in five isolated phenolic compounds. Two flavones, hispidulin (1) and jaceosidin (2), and the phenylethanoid glycosides, verbascoside (3), isoverbascoside (4), and conandroside (5), were identified and their chemical structures were determined by spectroscopic analyses. The insecticidal activity of compounds 1 and 2, in addition to 11 compounds isolated in a previous research (6–16), was evaluated against the Yellow Fever mosquito, Aedes aegypti. Four compounds displayed adulticidal activity with LD50 values of 2–2.3 μg/mosquito. Free radical scavenging properties of the plant extracts and compounds (1–5) were evaluated by measuring the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonate radical cation (ABTS•+) scavenging activity. All compounds exhibited notable activity, compared with the positive control, l-Ascorbic acid. This study suggests that N. oppositifolia could be a promising source of secondary metabolites, some with lethal adulticidal effect against Ae. aegypti.

The Insecticidal Activity of Artemisia absinthium leaves Extracts Against Blowfly,Chrysomya albiceps (Calliphoridae)

This study was carried out to evaluate the biological effects of methanolic, acetone and petroleum ether leaves extract of Artemisia absinthium against the 1st instar larvae of Chrysomya albiceps. All extracts have toxicity against the larvae of C. albiceps. The larvicidal, pupicidal and adulticidal activity of these extracts was varied depending on the solvent used in the extraction and the dose of the extract. Complete larval mortality percent (100%) was caused only by the petroleum ether extract of at 0.4g/ml with (Lc50 0.11 g/ml). Methanol and acetone extract had delayed toxic effects on pupae resulted from treated larvae. The toxicity of all plant extracts was extended to the adults that resulted from the treated larvae. Larval and pupal duration showed a significant increase. The growth index for treated larvae and resulted pupae was greatly affected by methanol and acetone extract. The highest retardation in growth was recorded at the highest concentration of 0.4g/ml by acetone leaves extract (2.2 vs. 8.4 for control).

Chemical characterization of billy goat weed extracts Ageratum conyzoides (Asteraceae) and their mosquitocidal activity against three blood-sucking pests and their non-toxicity against aquatic predators.

The petroleum ether crude extracts of A. conyzoides (Pe-Ac) were used to treat three medically intimidating pests of Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus, to evaluate their non-target screening against the mosquito predator. The chemical scanning of Pe-Ac through GC-MS analysis revealed a total of nine compounds and the maximum peak area was observed in 1,5-Heptadien-3-yne (22.14%). At the maximum dosage of Pe-Ac (200ppm), significant larvicidal activity was shown against the fourth instars of Ae. aegypti (96%), An. stephensi (93%), and Cx. quinquefasciatus (92%) respectively. The percentages of oviposition deterrence index (ODI) of all three mosquito vectors are maximum at the highest sub-lethal dosage of Pe-Ac (75ppm) and minimum at the control dosage. The sub-lethal dosage blocked the activity of carboxylesterase activity and upregulated the detoxifying enzyme activity in a dose-dependent way. The adulticidal activity of Pe-Ac showed that the maximum adult mortality rate (100%) was recorded at the prominent dosage of Pe-Ac 600ppm against the vectors of all three mosquitos at the maximum adulticidal time of 30min. Histopathological investigation of fourth instar larvae of all three mosquitos treated with a sub-lethal dosage of Pe-Ac showed that the midgut cells (epithelium, lumen, and peritrophic matrix) are ruptured completely whereas they appear to be normal in control larvae. The non-toxicity evaluation of Pe-Ac compared with the chemical toxin Temephos in aquatic predator Toxorhynchites splendens revealed that the plant extracts are harmless even at the prominent dosage (1000ppm) as compared to Temephos (1 and 2ppm) and displayed a higher mortality rate against the mosquito predators. Thus the safety index recommends that the Pe-Ac is more explicit to targets and a suitable auxiliary to chemical pesticides.

Toxicity of tobacco Nicotiana tabacum Linnaeus (Solanaceae) leaf extracts to the rice weevil Sitophilus oryzae Linnaeus 1763 (Coleoptera: Curculionidae)

BackgroundRice is the agricultural commodity with the third highest worldwide production and losses in rice storage due to insect pests may drastically affect the food availability for a large number of people. One of its serious pests in tropics is the “rice weevil”, Sitophilus oryzae. Although few effective fumigants are available, there is a global concern about environmental pollution, toxicity to non-target organisms, and pesticide residues. Botanicals are a promising source of pest control compounds as the pool of plants possessing insecticidal substances are enormous and have generated extraordinary interest in recent years as potential sources of natural insect control agents. The present study was conducted to determine the toxicity of tobacco (Nicotiana tabacum) leaf extracts as an alternative to synthetic insecticides in the management of rice weevils. The crude solvent leaf extracts of N. tabacum were analyzed for its phytochemical compounds via GC-MS and tested for its toxicity to the adults of S. oryzae at concentrations of 0.625, 1.25, 2.50, 5.00, 10.00, and 20.00 mg/L by Petri dish bioassay method. Adult mortality was calculated 24, 48, and 72 h after exposure.ResultsThe constituent compounds in the chloroform and acetone revealed 13 compounds represented by benzene carboxylic acid ester, alkaloids, and steroids. The major compounds found in GC-MS analysis are nicotine, nicotinonitrile, nornicotine, nicotinic acid, neonicotine, cotinine, indole, farnesol, sclareol, 9,12-octadecadienoic acid, squalene, palmitic acid, and 15-tetracosenoic acid methyl ester. Overall assessment indicates that the chloroform and acetone extracts of N. tabacum leaves exhibited the highest adulticidal activity against S. oryzae. Their LD50 values were 1.62, 0.64, and 0.48; 1.54, 0.83, and 0.48 mg/L after 24, 48, and 72 h of exposure respectively. In addition, the petroleum ether extract also indicated high adult mortality with LD50 value of 0.53 mg/L only at 72 h.ConclusionsThe present research has documented its first report for the management of rice weevil using tobacco leaf extracts, and therefore on the basis of the results of the present study, it is highly encouraging to note that the use of tobacco leaf extracts with its excellent insecticidal activity owing to the action of nicotine would be economically feasible to alleviate the rice weevil problem.

Cassia species: a potential source of biopesticides

Climate change is of significant concern for crop production as it affects crop pests and disease susceptibility, thus affecting crop health and causing a substantial decline in productivity. As the world warms, outbreaks of plant-eating insect pests are expected to intensify largely because warmer temperatures favor the pest’s biology, while boosting growth of the plants they eat. Globally, there is a high interest of finding novel botanical insecticides due to the drawbacks associated with the use of synthetic/chemical insecticides which include emergence of resistant pests, environmental pollution and various health problems such as cancer, skin itching, birth defects, infertility among others. Botanical pesticides are less toxic to the environment and public health since they are biodegradable and more specific to target pests. The current review focuses on the potential larvicidal, adulticidal, ovicidal, antifeedant and repellant activities of Cassia species against insects’ pests and plant diseases. Therefore, plant products from Cassia species may be utilized as promising biopesticides with commercial value as an alternative to synthetic pesticides.

Ovicidal, pupicidal, adulticidal, and repellent activity of Helicteres velutina K. Schum against Aedes aegypti L. (Diptera: Culicidae).

Aedes aegypti is a vector of emerging and neglected diseases, such as dengue, chikungunya, and Zika. Helicteres velutina, known as “pitó” in Brazil, is traditionally used as an insect repellent, and several studies have demonstrated its larvicidal activity. The aim of this study was to investigate this species and evaluate its potential ovicidal, pupicidal, adulticidal, and repellent activity. The viability of the eggs was evaluated using different concentrations of the test substances for 25 days. The hexane fraction killed 72.7% of the eggs, while dichloromethane killed 67.7%. The survival of the pupae and adults was verified after 72 h and 48 h, respectively. The LC50 for the hexane and dichloromethane fractions was 0.12 mg/mL and 8.85 mg/mL for pupae, 8.01 mg/mL and 0.74 mg/mL for adults (tarsal test), and 0.05 mg/mL and 0.23 mg/mL for adults (body test), respectively. Repellency was assessed for 240 min using neonatal Wistar rats on a Y-tube olfactometer. The hexane fraction attracted mosquitoes to the test chamber, while the dichloromethane fraction had a repellent action. The 7,4’-di-O-methyl-8-O-sulfate flavone provides greater repellency, and this finding is similar to the results of the in silico studies that have shown the potential of this substance against adult mosquitoes. This suggests that 7,4’-di-O-methyl-8-O-sulfate flavone may be one of the substances present in the extract from aerial parts of H. velutina that is responsible for the repellent activity mentioned in traditional medicine. These findings provide a better understanding of the insecticidal and repellent activity of the extract, fraction, and compounds isolated from H. velutina against Ae. aegypti, thereby revealing its potential in the development of a more effective botanical insecticide.

Anopheles gambiae larvicidal and adulticidal potential of Phyllanthus amarus (Schumach and Thonn, 1827) obtained from different localities of Nigeria

Objective: To screen phytochemicals in ethanolic leaf extracts of Phyllanthus amarus collected from three different geographical zones in Nigeria and evaluate their effects on larva and adult of Anopheles gambiae. Methods: The sample extracts of Phyllanthus amarus prepared with ethanol solvent were tested against Anopheles gambiae at two important developmental stages of its life cycle using slightly modified WHO protocols. Results: Alkaloids, saponins, tannins, flavonoids, glycosides, phenols, and terpenes were detected in each extract. Among these samples, the extract from northwest exhibited the highest larvicidal activity (LC50=263.02 ppm), followed by southeast and southwest extracts (LC50=288.40 and 295.12 ppm, respectively after 48 h), while the extract from southwest exhibited the highest adulticidal activity (LC50=275.42 ppm), followed by northwest and southeast extract (LC50=301.99 and 316.22 ppm, respectively after 24 h). A 50% larva mortality was almost attained at 600 ppm after 48 h duration of exposure to the northwest extract. Conclusions: The tested samples possess strong larvicidal and adulticidal property against Anopheles gambiae which depends on their chemical composition and localities of collection. Further studies are needed to explore the insecticidal activity against a wider range of mosquito species, and to identify active ingredient(s) of the extract responsible for such activity.

Repellent, larvicidal and adulticidal activities of essential oil from Dai medicinal plant Zingiber cassumunar against Aedes albopictus

Zingiber cassumunar is an important plant used in traditional medicine and as a natural mosquito repellent. However, the compounds responsible for the repellent activity of the plant are still unknown. The aim of the study is to identify the components of Z. cassumunar essential oil that show repellent activity against Aedes albopictus. We also evaluated the larvicidal and adulticidal activities of Z. cassumunar essential oil against Ae. albopictus. In-cage mosquito repellent experiments showed that Z. cassumunar essential oil possessed moderate repellent activity with a minimum effective dose (MED) of 0.16 ± 0.01 mg/cm2, compared to reference standard N,N-diethyl-3-methylbenzamide (DEET, 0.03 ± 0.01 mg/cm2). Bioassay-guided fractionation identified the major active compound of Z. cassumunar essential oil as (−)-terpinen-4-ol (1) (MED: 0.19 ± 0 mg/cm2). We also found that Z. cassumunar essential oil showed moderate larvicidal activity against first instar larvae of Ae. albopictus with a LC50 (50% lethal concentration) of 44.9 μg/L after 24 h. Fumigation bioassays showed that Z. cassumunar essential oil exhibits moderate adulticidal activity against Ae. albopictus with a LC50 of 5.44%, while (−)-terpinen-4-ol showed significant adulticidal activity with a LC50 of 2.10% after 24 h. This study verifies that the Z. cassumunar essential oil has mosquito repellent activity, and that (−)-terpinen-4-ol is mainly responsible for this activity. Furthermore, this study provides scientific support for the folk usage of Z. cassumunar essential oil as mosquito repellent and indicates that Z. cassumunar essential oil and (−)-terpinen-4-ol can be used as plant-derived repellents and insecticides for mosquito control.

The potential use of Azolla pinnata\xa0as an alternative bio-insecticide

Four different tests showed the effectiveness of Azolla pinnata plant extracts against Aedes aegypti and Aedes albopictus mosquitoes. In the adulticidal test, there was a significant increase in mortality as test concentration increases and A. pinnata extracts showed LC50 and LC95 values of 2572.45 and 6100.74 ppm, respectively, against Ae. aegypti and LC50 and LC95 values of 2329.34 and 5315.86 ppm, respectively, against Ae. albopictus. The ovicidal test showed 100% eggs mortality for both species tested for all the concentrations tested at 1500 ppm, 1000 ppm, 500 ppm, 250 ppm and 125 ppm. Both tested samples of Ae. aegypti and Ae. albopictus did not lay any eggs in the plastic cups filled with the A. pinnata extract but instead opted to lay eggs in the plastic cups filled with water during the oviposition deterrence test. Similarly, the non-choice test of Ae. aegypti mosquitoes laid eggs on the sucrose solution meant for the nutrient source of the mosquitoes instead of in the plastic cup that was designed to facilitate oviposition filled with the extract. This clearly indicates the presence of bioactive compounds which are responsible in adulticidal and ovicidal activity in Aedes mosquitoes and at the same time inducing repellence towards the mosquitoes. The LC–MS results showed mainly three important chemical compounds from A. pinnata extracts such as 1-(O-alpha-D-glucopyranosyl)-(1,3R,25R)-hexacosanetriol, Pyridate and Nicotinamide N-oxide. All these chemicals have been used for various applications such as both emulsion and non-emulsion type of cosmetics, against mosquito vector such as Culex pipens and Anopheles spp. Finally, the overall view of these chemical components from A. pinnata extracts has shown the potential for developing natural product against dengue vectors.

Adulticidal activity of plant oil of Lavandula latifolia against the selected mosquito species

Adulticidal activity of plant oil of Lavandula latifolia against the selected mosquito species

EVALUATION OF NOVEL NANOPARTICLES AGAINST Tetranychus urticae AND ITS PREDATORY MITE Amblyseius gossipi

The present study was carried out to evaluate the relative biological activity of six treatments. Four nanoparticles (chitosan, Hydroxyapatite, chitosan hydroxyapatite and silver hydroxyapatite), one bio-agent effective microorganisms (EMs) compared to one synthetic acricide (bifenzata) were tested against the female adults and eggs of Tetranychus urticae and its predatory mite Amblyseius gossipi using standardized method of bioassay under laboratory conditions. Effect of the tested agents on the activity of carbohydrates enzymes, total lipid and total protein content were determined. The results revealed that chitosan (NPs) showed significantly adulticidal activity against T. urticae. Furthermore, EMs was the most effective treatment on the eggs of T. urticae followed by bifenzata under laboratory conditions. Therefore, nanoparticles and EMs appeared to be highly safe and selective against Amblyseius gossipi. This study suggests the possible use of nanoparticles as safe alternatives to conventional acaricides and compatible with integrated pest management practices. They might be contribute to future applications in pest control for sustainable agriculture.

Plant Natural Products for the Control of Aedes aegypti: The Main Vector of Important Arboviruses.

The mosquito species Aedes aegypti is one of the main vectors of arboviruses, including dengue, Zika and chikungunya. Considering the deficiency or absence of vaccines to prevent these diseases, vector control remains an important strategy. The use of plant natural product-based insecticides constitutes an alternative to chemical insecticides as they are degraded more easily and are less harmful to the environment, not to mention their lower toxicity to non-target insects. This review details plant species and their secondary metabolites that have demonstrated insecticidal properties (ovicidal, larvicidal, pupicidal, adulticidal, repellent and ovipositional effects) against the mosquito, together with their mechanisms of action. In particular, essential oils and some of their chemical constituents such as terpenoids and phenylpropanoids offer distinct advantages. Thiophenes, amides and alkaloids also possess high larvicidal and adulticidal activities, adding to the wealth of plant natural products with potential in vector control applications.