Chemical composition and activity of an Ocimum basilicum essential oil on Culex pipiens larvae: Toxicological, biometrical and biochemical aspects

The current study was undertaken in order to determine the chemical composition of the leaf essential oils of Lavandula dentata L. (Lamiaceae) cultivated in Tebessa (Algeria) and to evaluate its potential larvicidal activity against fourth instar larvae of Culiseta longiareolata Macquart and Culex pipiens L. (Diptera: Culicidae). The essential oil content of L. dentata leaves obtained by hydrodistillation was 1.18%dry weight. The chemical analysis performed by gas chromatography-mass spectrometry showed that this essential oil contained eight compounds. The major chemical constituents identified were a-terpinolene (51.13 %) and camphor (13.43 %). Bioassay test done following the World Health Organization standard protocol revealed that this essential oil exhibited larvicidal activity. The LC50 and LC90 values against fourth instar larvae were 77.09 and 104.45 ppm for Cs. longiareolata and 113.38 and 150.38 ppm for Cx. pipiens, respectively. The results proved the potential use of this natural product as an alternative to synthetic insecticides for controlling mosquitoes.

https://bioone.org/journals/African-Entomology/volume-25/issue-2/003.025.0387/iLavandula-dentata-i-Essential-Oils--Chemical-Composition-and-Larvicidal/10.4001/003.025.0387.pdf

Lavandula dentata Essential Oils: Chemical Composition and Larvicidal Activity Against Culiseta longiareolata and Culex pipiens (Diptera: Culicidae)

The efficacy of pyriproxyfen, a juvenile hormone analog (JHA), was evaluated using third instar larvae of Drosophila melanogaster Meigen, 1830 (Diptera: Drosophilidae). Various doses of the compound, ranging from 0.01 to 2 ng/larva, were applied topically to larvae (12 h before pupariation). Treatment did not prevent pupariation but inhibited adult emergence at all the doses tested. In a second series of experiments the ecdysteroid content of pupae was determined following application of pyriproxyfen at two doses, 0.108 and 0.29 ng/larva, corresponding to ID25 and ID50, the doses required for 25 and 50% inhibition of adult emergence, respectively. Pyriproxyfen treatment increased the duration of pupal development. In addition, enzyme immunoassay measurements of ecdysteroids in whole body extracts of pupae indicated that pyriproxyfen decreased the ecdysteroid content in a dose-dependent manner. Finally, the effects on the cuticle of pyriproxyfen (ID50) were studied histologically, which revealed that this compound increased the thickness of the new adult cuticle and suppressed the formation of bristles. Biochemical analyzes revealed that an increase in chitin content of the cuticle is only recorded at the highest dose. Thus, a topical application of pyriproxyfen to third instar larvae interfered with the molting hormone and disrupted the normal development of this insect.

/pdf/evaluation-of-pyriproxyfen-a-juvenile-hormone-analog-on-1blwflxazp.pdf

Evaluation of pyriproxyfen, a juvenile hormone analog, on Drosophila melanogaster (Diptera: Drosophilidae): Insecticidal activity, ecdysteroid contents and cuticle formation

To overcome those problems caused by repeated and indiscriminate uses of conventional insecticides, it is necessary to seek environmentally safe and low-cost alternatives for pest control. Among the effective alternatives are anti-JH compounds. The present articlewas prepared aiming to present an updated overview of different categories of compounds possessing anti-JH activity and their effects on survival, growth, development, metamorphosis, and reproduction of several insects of different orders. This article focused, also, on the effects of these compounds of other physiological processes in insects, such as polyphenism, behavior, diapause, metabolism, enzymatic activities, chemoreceptors and pheromone production, as well as their antifeedant effects against some insect pests. Compounds with anti-JH activity are considered as new representatives of IGRs lacking some disadvantages of juvenoid-type chemicals. In this review we described some advantageous uses of some anti-JH compounds, imidazoles in particular, in the sericulture and silk research fields. In addition, it shed some light on the action mechanisms of anti-JH agents and described the fate of them in the insect body. It is obvious from the present review that the practical use of anti-JH compounds in the pest management has been challenged by some limitations and restrictions. These compounds should be assessed against different insect pests under field conditions. However, these anti-JH agents can be considered as new leads for devising fourth generation insecticides. On the other hand, some of the anti-JH analogues of imidazoles have been successfully used in the practical production of natural silkin the world.

https://eajbsa.journals.ekb.eg/article_11687_6a4beb358408e0a734f5aa0db11bf0dc.pdf

Physiological Activities of Anti-Juvenile Hormone Agents Against Insects and Their Role For Devising Fourth Generation Insecticides: A Comprehensive Review

Essential Oils‐loaded Bio‐nanomaterials for Sustainable Agricultural Applications

Aims: In the present study, the objective was to estimate the toxicity of an insect growthregulator with juvenile hormone-like activity, kinoprene, on Culex pipiens, the mostabundant and investigated mosquito species. Effects of this compound on growth anddevelopment were also evaluated.Methodology: A commercial formulation (Enstar 65% EC) was tested at differentconcentrations ranging between 162.5 and 650µg/L on newly molted fourth-instar larvaethat were exposed for 24 h under standard laboratory conditions according to WorldHealth Organization recommendations.Results: Kinoprene exhibited insecticidal activity by direct action on the treated fourth-instar larvae but also by differed action on the other following stages of development.Mortality occurred after earlier inhibition of their development or by their inability tocomplete their ecdysis. The LC 50 values were 1287.4µg/L for the direct action on fourthinstar larvae, and 246.8µg/L for the differed action until adult emergence. Moreover, thecompound disturbed growth and development since several morphological types and anincrease in the duration of larval and pupal stages were recorded. In a second series ofexperiments, the effects of kinoprene were examined on morphometric measurements ofOriginal Research Article

/pdf/laboratory-evaluation-of-a-biorational-insecticide-kinoprene-24ezvyh5rq.pdf

Laboratory Evaluation of a Biorational Insecticide, Kinoprene, against Culex pipiens Larvae: Effects on Growth and Development

Current researches for mosquito control have focused on insect specific insecticides without environmental concerns. The present study was conducted to evaluate the Ovicidal activity of an ecdysone agonist (methoxyfenozide) on Culex pipiens L. (Culicidae: Diptera) under laboratory conditions using standard WHO protocol. Lethal concentrations (LC50= 24.54 µg/L and LC90= 70.79 µg/L) previously determined were tested against freshly laid eggs. The egg viability was examined and the deferred effects of treatment were also investigated on the development duration and the sex ratio. Data obtained show that egg hatching inhibition was dose dependent, with a reduction of 13.44% and 46.99% with LC50 and LC90, respectively. In treated groups, the total development duration was significantly longer as compared to controls. The adult sex - ratio was significantly skewed in favor of males emerged from treated eggs with LC50 and LC90 of methoxyfenozide. Moreover, changes in the egg shell morphology and abnormal egg hatching pattern were observed. Morphologic abnormalities in larva were also recorded. Data from the current investigation clearly demonstrated that methoxyfenozide possess remarkable larvicidal and ovicidal activities against a medically important vector as ideal eco-friendly approach for mosquito’s control.

https://www.entomoljournal.com/archives/2016/vol4issue4/PartM/4-4-43-425.pdf

Ovicidal activity of an insect growth disruptor (methoxyfenozide) against Culex pipiens L. and delayed effect on development

Methoxyfenozide is an insect growth disruptor belonging to the class of nonsteroidal ecdysone agonists. In the present study, methoxyfenozide (23% emulsifiable concentrate) is evaluated against newly molted fourth‐instar larvae of Culex pipiens L. and Culiseta longiareolata Macquart (Diptera: Culicidae), aiming to investigate its possible effects on growth and development. Larvae are exposed for 24 h under standard laboratory conditions in accordance with World Health Organization recommendations. The product is found to exhibit insecticidal activity against the two tested mosquito species with a concentration–response relationship. Moreover, based on the lethal concentrations determined, methoxyfenozide is slightly more toxic against C. pipiens than C. longiareolata. Furthermore, fourth‐instar larva of the two mosquito species are treated using two lethal concentrations (LC50 and LC90) of methoxyfenozide, and then individual survivals (larvae, pupae and adults) from larval treatment are subjected to a biometrical and biochemical study. The compound is found to interfere with growth by reducing the larval and pupal development duration. Moreover, the body volume and the main biochemical contents (proteins, carbohydrates and lipids) from different stages are affected. The overall results suggest that the ecdysone agonist under investigation interferes with the development process and has potential for mosquito control.

Activity of a selective insecticide (methoxyfenozide) against two mosquito species (Culex pipiens and Culiseta longiareolata): toxicological, biometrical and biochemical study

Stored grains could lose substantially their nutritional quality, and consequently its value, between storage and consummation because of insect’s infestation. One of the most frequent pests of wheat is the grain weevil (Sitophilus granarius L.). Cleverly hidden, the immature stages of this destructive pest are very difficult to identify. Protecting stored grains has become an agricultural challenge. In the present study, the essential oil (EO) distillated from Citrus limonum (L.) (Burm. F., 1768) and analyzed by gas chromatography-mass spectrometry (GC-MS) revealed the presence of 47 compounds with (Z)-citral (30.74%), dl-limonene (19.81%) and geranyl propionate (16.28%) as major components. In a second series of experiment, its fumigant (using filter paper), repellent (by semi circles joined discs) and residual (persistent insecticidal activity) activities were examined against Sitophilus granarius (L.) adults. The total nutrition (carbohydrates and lipids) depletion index (NDI) was also calculated. Residual toxicity and repellency of EO were demonstrated after fumigation against S. granarius with a dose-response relationship. The effectiveness of EO was exposure time dependent and its residual activity persisted up to 30 h following mortality. Moreover, data showed that treatment of S. granarius adults had adverse effects on the depletion of their energy reserves. C. limonum EO declined the lipid and carbohydrate contents in adults. Obtained data prove that botanical essential oils could be considered as potent biorational alternatives to synthetic insecticides for pest control of stored products in a sustainable manner.

Effect of Citrus limonum essential oil against granary weevil, Sitophilus granarius and its chemical composition, biological activities and energy reserves

An essential oil extracted from bay laurel, Laurus nobilis (L.), was chemically characterized and tested against fourth-instar Culiseta longiareolata (Macquart) (Diptera: Culicidae). Perce...

https://bioone.org/journals/journal-of-entomological-science/volume-55/issue-2/0749-8004-55.2.262/Chemical-Composition-and-Bioefficacy-of-Essential-Oil-from-Bay-Laurel/10.18474/0749-8004-55.2.262.pdf

Chemical Composition and Bioefficacy of Essential Oil from Bay Laurel Shrub (Laurales: Lauraceae) against Culiseta longiareolata (Macquart) (Diptera: Culicidae) Larvae

Kaouther Hamaidia

Papers

Laboratory Evaluation of a Biorational Insecticide, Kinoprene, against Culex pipiens Larvae: Effects on Growth and Development

Ovicidal activity of an insect growth disruptor (methoxyfenozide) against Culex pipiens L. and delayed effect on development

Activity of a selective insecticide (methoxyfenozide) against two mosquito species (Culex pipiens and Culiseta longiareolata): toxicological, biometrical and biochemical study

Effect of Citrus limonum essential oil against granary weevil, Sitophilus granarius and its chemical composition, biological activities and energy reserves

Chemical Composition and Bioefficacy of Essential Oil from Bay Laurel Shrub (Laurales: Lauraceae) against Culiseta longiareolata (Macquart) (Diptera: Culicidae) Larvae