Insecticidal Activities of the Leaf Oils of EightCinnamomum. species AgainstAedes aegypti. andAedes albopictus.

Abstract

The leaf oils of eight Cinnamomum species (C. rhyncophyllum Miq., C. microphyllum Ridl., C. pubescens Kochummen, C. mollissimum Hook. f., C. impressicostatum Kosterm, C. scortechinii Gamb., C. sintoc Bl., and C. cordatum Kosterm) were investigated for their larvicidal and adulticidal activities against Aedes aegypti (Aedes aegypti Lynn) and Aedes albopictus (Aedes albopictus Skuse). Acute mortalities of the fourth instar larvae and the adult mosquitoes were determined according to the standard WHO methods. Among the essential oils studied, the leaf oils of C. rhyncophyllum, C. microphyllum, C. pubescens, C. mollissimum, and C. impressicostatum showed significant effects against the larvae of Ae. aegypti and Ae. albopictus with concentrations that caused 50% mortality (LC 50 ) values of less than 12.8 and 11.8 mg ml À1 , respectively. The essential oils that showed strong larvicidal effects also demonstrated relatively strong adulticidal effects on the mosquitoes after 3 h exposure with LC 50 values ranging from 133.0 to 243.0 mg ml À1 against Ae. aegypti and from 118.0 to 194.0 mg ml À1 against Ae. albopictus. The efficacy of the oils toward the larvae and adult mosquitoes of both species was nonselective as the LC 50 values showed little variation. The chemical composition of the oils was investigated by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). This study suggested that the essential oils containing high levels of benzyl benzoate and benzyl salicylate exhibited strong insecticidal activities against the larvae and adult mosquitoes.

Larvicidal, ovicidal, and oviposition-deterrent activities of four plant extracts against three mosquito species

“…The search for new strategies with natural products to control destructive insects and vectors of diseases is desirable due to the prevalence of vector resistance to synthetic insecticides, problem of toxicity, non-biodegradable effects, and effects on non-target organisms (Jantan et al 2005). Extracts from plants may be alternative sources of mosquito control agents since they constitute rich sources of bioactive compounds that are biodegradable into non-toxic products and potentially stable (Amer and Melhorn 2006).…”

Larvicidal Activity of Essential Oil Derived from <i>Illicium henryi</i> Diels (Illiciaceae) Leaf

“…In the previous studies, one of the major constituent, safrole was found to possess larvicidal activity against two mosquitoes, A. aegypti and A. albopictus [21,22]. However, myristicin was shown to have contact and fumigant toxicity against several insect/mites and to exhibit strong synergistic activity because it has been demonstrated to possess strong inhibitory effects on many P450s, such as houseflies (Musca domestica) [23], hairy caterpillars (Spilarctia obliqua) [24], armyworms (Pseudaletia unipuncta) [25], navel orangeworm (Amyelois transitella) [26], and house dust mites (Dermatophagoides farinae, D. pteronyssinus) and mould mites (Tyrophagus putrescentiae) [27].…”

Chemical composition and mosquito larvicidal activities of Salvia essential oils

“…The search for new strategies or natural products to control vectors of diseases is desirable due to the prevalent occurrence of vector resistance to synthetic insecticides and the problem of toxic nonbiodegradable residues contaminating the environment and undesirable effects on nontarget organisms (Jantan et al, 2005). Essential oils from plants may be an alternative source of mosquito larval control agents, since they constitute a rich source of bioactive compounds that are biodegradable and potentially suitable for use in integrated management programs.…”

“…Essential oils from plants may be an alternative source of mosquito larval control agents, since they constitute a rich source of bioactive compounds that are biodegradable and potentially suitable for use in integrated management programs. Much effort has, therefore, been focused on the effectiveness of plant essential oils against mosquito larvae because of their broad spectrum of activity against insects, low mammalian toxicity, and ability to degrade rapidly in the environment (Jantan et al, 2005;Morais et al, 2007;Cheng et al, 2008;Silva et al, 2008).…”