Mosquitoes (Diptera: Culicidae) are a huge threat for millions of people worldwide, since they act as vectors for devastating parasites and pathogens. Culicidae control is of crucial importance. Mosquito eggs, larvae, and pupae are usually targeted using organophosphates, insect growth regulators, and microbial agents. Indoor residual spraying and insecticide-treated bed nets are also employed. However, these chemicals have negative effects on human health and the environment, and induce resistance in a number of species. Eco-friendly tools have been recently implemented against mosquito vectors, including botanical insecticides. The majority of researches focused on larvicides (745 SCOPUS results, July 2015) and adult repellents (434 SCOPUS results), while limited efforts were conducted to identify effective ovicides of botanical origin (59 SCOPUS results). Here, I review current knowledge on the effectiveness of plant-borne ovicides against major mosquito vectors of medical and veterinary importance. The majority of researches focused on the toxicity of crude extracts, their fractions, or essential oils against three important mosquito vectors, Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus. As a general trend, C. quinquefasciatus eggs were the most resistant to botanical ovicides. Five studies proposed selected compounds from plant extracts and essential oils as ovicides effective at few parts per million. However, no efforts were conducted to shed light on possible mechanisms underlying the toxicity of plant-borne ovicides. In the final section, a number of hot issues needing further research and cooperation among parasitologists, entomologists, and researchers working in natural product chemistry are outlined.

Plant-borne ovicides in the fight against mosquito vectors of medical and veterinary importance: a systematic review

Plant extracts for developing mosquito larvicides: From laboratory to the field, with insights on the modes of action.

BACKGROUND
Travellers are confronted with a variety of vector-borne threats. Is one type of repellent effective against all biting vectors? The aim of this review is to examine the literature, up to December 31st, 2012, regarding repellent efficacy.


METHODS
We searched PubMed for relevant papers. Repellents of interest were DEET, Icaridin as well as other piperidine-derived products (SS220), Insect Repellent (IR) 3535 (ethyl-butylacetyl-amino-propionat, EBAAP) and plant-derived products, including Citriodora (para-menthane-3,8-diol). As vectors, we considered the mosquito species Anopheles, Aedes and Culex as well as the tick species Ixodes. We selected only studies evaluating the protective efficacy of repellents on human skin.


RESULTS
We reviewed a total of 102 publications. Repellents were evaluated regarding complete protection time or as percentage efficacy [%] in a time interval. We found no standardized study for tick bite prevention.


CONCLUSIONS
Regarding Aedes, DEET at concentration of 20% or more, showed the best efficacy providing up to 10 h protection. Citriodora repellency against this mosquito genus was lower compared to the other products. Also between subspecies a difference could be observed: Ae. aegypti proved more difficult to repel than Ae. Albopictus. Fewer studies have been conducted on mosquito species Anopheles and Culex. The repellency profile against Anopheles species was similar for the four principal repellents of interest, providing on average 4-10 h of protection. Culex mosquitoes are easier to repel and all four repellents provided good protection. Few studies have been conducted on the tick species Ixodes. According to our results, the longest protection against Ixodes scapularis was provided by repellents containing IR3535, while DEET and commercial products containing Icaridin or PMD showed a better response than IR3535 against Ixodes ricinus. Many plant-based repellents provide only short duration protection. Adding vanillin 5% to plant-based repellents and to DEET repellents increased the protection by about 2 h.

The efficacy of repellents against Aedes, Anopheles, Culex and Ixodes spp. e A literature review

The efficacy of repellents against Aedes, Anopheles, Culex and Ixodes spp. - a literature review.

Mosquitoes are blood-feeding insects and serve as the most important vectors for spreading human diseases such as malaria, yellow fever, dengue fever, and filariasis. The continued use of synthetic insecticides has resulted in resistance in mosquitoes. Synthetic insecticides are toxic and affect the environment by contaminating soil, water, and air, and then natural products may be an alternative to synthetic insecticides because they are effective, biodegradable, eco-friendly, and safe to environment. Botanical origin may serve as suitable alternative biocontrol techniques in the future. Mentha spicata, an edible and medicinal plant, is chiefly distributed in Southeast Asia and South Asia. In the present study, the toxicity of mosquito larvicidal activity of leaf essential oil (EO) and their major chemical constituents from Mentha spicata against Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi. The chemical composition of the leaf EO was analyzed using gas chromatography–mass spectroscopy (GC-MS). GC-MS revealed that the EO of M. spicata contained 18 compounds. The major chemical components identified were carvone (48.60%), cis-carveol (21.30%), and limonene (11.30%). The EO had a significant toxic effect against early third-stage larvae of C. quinquefasciatus, A. aegypti, and A. stephensi with LC50 values of 62.62, 56.08, and 49.71 ppm and LC90 values of 118.70, 110.28, and 100.99 ppm, respectively. The three major pure constituents extracted from the M. spicata leaf EO were also tested individually against three mosquito larvae. The LC50 values of carvone, cis-carveol, and limonene appeared to be most effective against A. stephensi (LC50 19.33, 28.50, and 8.83 ppm) followed by A. aegypti (LC50 23.69, 32.88, and 12.01 ppm), and C. quinquefasciatus (LC50 25.47, 35.20, and 14.07 ppm). The results could be useful in search for newer, safer, and more effective natural larvicidal agents against C. quinquefasciatus, A. aegypti, and A. stephensi.

Chemical composition and larvicidal activity of essential oil from Mentha spicata (Linn.) against three mosquito species

Objective
To determine the ovicidal and repellent activities of methanol leaf extract of Ervatamia coronaria (E. coronaria) and Caesalpinia pulcherrima (C. pulcherrima) against Culex quinquefasciatus (Cx. quinquefasciatus), Aedes aegypti (Ae. aegypti) and Anopheles stephensi (An. stephensi).

Ovicidal and repellent activities of botanical extracts against Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi (Diptera: Culicidae).

Mosquito-borne diseases have an economic impact, including loss in commercial and labor outputs, particularly in countries with tropical and subtropical climates; however, no part of the world is free from vector-borne diseases. In mosquito control programs, botanical origin may have the potential to be used successfully as eggs, larvae, and adult. The larvicidal, ovicidal, and repellent activities of crude benzene and ethyl acetate extracts of leaf of Ervatamia coronaria and Caesalpinia pulcherrima were assayed for their toxicity against three important vector mosquitoes, viz., Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus (Diptera: Culicidae). The larval mortality was observed after 24 h of exposure. All extracts showed moderate larvicidal effects; however, the highest larval mortality was found in benzene extract of E. coronaria against the larvae of Anopheles Stephensi, Aedes aegypti, and Culex quinquefasciatus with the LC(50) and LC(90) values were 79.08, 89.59, and 96.15 ppm and 150.47, 166.04, and 174.10 ppm, respectively. Mean percent hatchability of the ovicidal activity was observed 48 h posttreatment. The percent hatchability was inversely proportional to the concentration of extract and directly proportional to the eggs. The leaf extract of E. coronaria was found to be most effective than Caesalpinia pulcherrima against eggs/egg rafts of three vector mosquitoes. For E. coronaria, the benzene extract exerted 300, 250, and 200 ppm against Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus, respectively. The results of the repellent activity of benzene and ethyl acetate extract of E. coronaria and Caesalpinia pulcherrima plants at three different concentrations of 1.0, 2.5, and 5.0 mg/cm(2) were applied on skin of fore arm in man and exposed against adult female mosquitoes. In this observation, these two plant crude extracts gave protection against mosquito bites without any allergic reaction to the test person, and also, the repellent activity is dependent on the strength of the plant extracts. These results suggest that the leaf solvent plant extracts have the potential to be used as an ideal ecofriendly approach for the control of mosquitoes. This is the first report on the mosquito larvicidal, ovicidal, and repellent activities of the reported E. coronaria and Caesalpinia pulcherrima plants.

Mosquito larvicidal, ovicidal, and repellent properties of botanical extracts against Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus (Diptera: Culicidae)

The larvicidal and ovicidal effects of seven medicinal plant oil were investigated against the fourth-instar larvae of S.litura, (Lepidoptera: Noctuidae). The aim of this study was to evaluate the toxic effects of Zingiber officinale, Ocimum basilicum, cyperus scariosus, Pimpinella anism, Nigella sativa, Rosmarinus officinais, and Cercuma longa were exposed to different concentrations. All essential oils showed moderate toxic effect on lepidopteran agricultural pest of armyworm after 24hr of exposure; However, the highest larvel mortality was found in (Table 1) The leaf of O.basiliucm, The rhizone of Z.officinale, the rhizome of C.longa and the shoot of C.Scariosus (LC50 = 27.3, 29, 30.6, 31.2, LC95 = 43.6, 48.2, 56 and 51.4 ppm) and lowest larvel mortality was recorded the p.anisum (LC50 = 38.5 and LC95 = 78 ppm). Respectively chi-square value was significant at P<0.05 level. Ovicidal activitiy of above mentioned the seven medicinal plant essential oil were used in the study. During preliminary screening, the essential oil wer etested at different concentrations (50, 100, 150, 200, 250 and 300 ppm). The percentage of eggs hatchability was assessed 120 hr post treatment (Table 2). All essential oil showed moderate ovicidla effects; however, the highest Ovicidal activity was found in O.basilicum and Z.officinale. S.litura eggs was 100% of mortality (No hatchability) recorded at 200, 250 and 300 ppm concentration of O.basilicum, Z. Officinale, C.longa, and C.Scariosus may serve as lepidopteran agricultural pest of armyworm control in their oil form, essential oil have the potential to be used as an ideal eco-friendly approach for the control of agricultural pest of S.litura. © 2010 IJRSR. All rights reserved.

Larvicidal and ovicidal activity of seven essential oil against lepidopteran pest S.litura (lepidoptera: noctuidae)

The present investigation revealed that the volatile oils obtained from Cinnamomum camphora, Citrus limonum, Cuminum cyminum, Ocimum basiticum, Menthe gruensism, Menthe piperata, Rosmarinus officinalis, Thymus vulgaris, Pelargonium graveolens ,and Coriandrum sativum .Medicinal plant species were tested for their antifeedant activitiy against Spodoptera litura fourth instar larvae by using a Ricinus communis bioassay. Responses varied according to plant species, dose, and exposure time. The antifeedant activitiy was observed after 24 h of exposure. All Essential oil are showed moderate antifeedant activitiy; however, the highest antifeedant activitiy was observed in the essential oil of Cuminum cyminum, Menthe piperata, Rosmarinus officinalis, Thymus vulgaris and Coriandrum sativum exhibited (100%)complete antifeedant activity at 6mg/cm 2 over a 24 hours period and moderate antifeedant activitiy was observed in the essential oil of Cinnamomum camphora ,Citrus limonum, Ocimum basiticum, Menthe gruensis and Pelargonium graveolens at 6mg/cm 2 over a 24 hours period. However, all essential oil are showed lowest antifeedant activitiy was observed at 2mg/cm 2 and 4mg/cm 2 over a 24 hours period. The plant essential oil described merit further study as potential antifeedant or insecticidal agents against army worm, Spodoptera litura. Keyworkds: Natural insecticide, Antifeedant activity, Essential oil, Spodoptera litura.

Antifeedant activity of medicinal plant essential oils against Spodoptera litura (lepidoptera:noctuidae)

Plant essential oil, especially botanical insecticides, are currently studied more and more because of the possibility of their use in plant protection. Biological activity of fifteen essential oil were studied using fourth instar larvae of armyworm, Spodoptera litura (Lepidoptera: Noctuidae).Larvicidal activity of Acorus calamus, Cinnamomum camphora, Citrus limonum, Cuminum cyminum, Cymbopogan citrates, Ocimum basilicum, Origanum compactum, Origanum vulgare, Mentha arvensis, Mentha piperata, Rosmarinus officinalis, Thymus vulgaris, Pelargonium graveolens, Zingiber officinales, and Coriandrum sativumwere used in this study. During preliminary screening, the extracts were tested at 1,000 ppm concentration. The larval mortality was observed after 24 h of exposure. All Essential oil are showed moderate larvicidal effects; however, the highest larval mortality was found in the essential oil of Zingiber officinales, Citrus limonum , Acorus calamus, Rosmarinus officinalis, Ocimum basilicum, Cuminum cyminum ,and Coriandrum sativum (LC50=15, 34.55, 36.13, 38.2, 57.55, 63.99 and 65.07 ppm) and the lowest larval mortality was found in the essential oil of Origanum vulgare, Cinnamomum camphora, Cymbopogan citrates , Mentha arvensis and Pelargonium graveolens (LC50= 110.77, 112.03, 114.43, 120.59 and 134.27ppm) The result that the Essential oils promising as larvicidal activity against armyworm, Spodoptera litura agricultural important lepidopteron pest. © 2010 IJRSR. All rights reserved. Keyworkds: Spodoptera litura, larvicidal activity, Essential oils.

T. Mathivanan

Papers

Ovicidal and repellent activities of botanical extracts against Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi (Diptera: Culicidae).

Mosquito larvicidal, ovicidal, and repellent properties of botanical extracts against Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus (Diptera: Culicidae)

Larvicidal and ovicidal activity of seven essential oil against lepidopteran pest S.litura (lepidoptera: noctuidae)

Antifeedant activity of medicinal plant essential oils against Spodoptera litura (lepidoptera:noctuidae)

Certain essential oil against the field pest army worm, spodoptera litura (lepidoptera:noctuidae)