Insecticidal and feeding deterrent activities of essential oils in the cabbage looper,Trichoplusia ni (Lepidoptera: Noctuidae)

Ten essential oils were tested against the cabbage looper, Trichoplusia ni larvae for contact, residual and fumigant toxicities and feeding deterrent effects. Against third instar T. ni, Syzygium aromaticum (LD₅₀ = 47.8 μg/larva), Thymus vulgaris (LD₅₀ = 52.0 μg/larva) (the two positive controls) and Cinnamomum glanduliferum (LD₅₀ = 76.0 μg/larva) were the most toxic via topical application. Litsea pungens (LD₅₀ = 87.1 μg/larva), Ilex purpurea (LD₅₀ = 94.0 μg/larva), Cinnamomum cassia (LD₅₀ = 101.5 μg/larva) and Litsea cubeba (LD₅₀ = 112.4 μg/larva) oils were equitoxic. Thymus vulgaris (LC₅₀ = 4.8 mg/ml) and S. aromaticum (LC₅₀ = 6.0 mg/ml) oils were the most toxic in residual bioassays. Cymbopogon citratus (LC₅₀ = 7.7 mg/ml) and C. cassia (LC₅₀ = 8.5 mg/ml) oils were equitoxic followed by Cymbopogon nardus (LC₅₀ = 10.1 mg/ml) in this bioassay. The remaining five oils showed little or no residual effects. In a fumigation bioassay, L. cubeba (LC₅₀ = 16.5 μl/l) and I. purpurea (LC₅₀ = 22.2 μl/l) oils were the most toxic. Cinnamomum glanduliferum (LC₅₀ = 29.7 μl/l) and Sabina vulgaris (LC₅₀ = 31.2 μl/l) oils were equitoxic. Interestingly, S. aromaticum did not exhibit any fumigant toxicity. Cymbopogon citratus, C. nardus and C. cassia strongly deterred feeding by third instar T. ni (DC₅₀s = 26.9, 33.8 and 39.6 μg/cm², respectively) in a leaf disc choice bioassay. The different responses of T. ni larvae to the oils in different bioassays suggest that these essential oils exhibit different modes of action. Based on their comparable efficacy with essential oils already used as active ingredients in many commercial insecticides (i.e. clove oil and thyme oil), some of these essential oils may have potential as botanical insecticides against T. ni.     

Chemical Constituents and Insecticidal Activities of Ajania fruticulosa Essential Oil

The insecticidal activity and chemical constituents of the essential oil from Ajania fruticulosa were investigated. Twelve constituents representing 91.0% of the essential oil were identified, and the main constituents were 1,8‐cineole ( 41.40% ), (+)‐camphor ( 32.10% ), and myrtenol (8.15%). The essential oil exhibited contact toxicity against Tribolium castaneum and Liposcelis bostrychophila adults with LD₅₀ values of 105.67 μg/adult and 89.85 μg/cm², respectively. The essential oil also showed fumigant toxicity against two species of insect with LC₅₀ values of 11.52 and 0.65 mg/l, respectively. 1,8‐Cineole exhibited excellent fumigant toxicity (LC₅₀ = 5.47 mg/l) against T. castaneum. (+)‐Camphor showed obvious fumigant toxicity (LC₅₀ = 0.43 mg/l) against L. bostrychophila. Myrtenol showed contact toxicity (LD₅₀ = 29.40 μg/cm²) and fumigant toxicity (LC₅₀ = 0.50 mg/l) against L. bostrychophila. 1,8‐Cineole and (+)‐camphor showed strong insecticidal activity to some important insects, and they are main constituents of A. fruticulosa essential oil. The two compounds may be related to insecticidal activity of A. fruticulosa essential oil against T. castaneum and L. bostrychophila.     

Insecticidal Activity and Chemical Composition of Artemisia sieben Besser Essential Oil from Karaj,Iran

Atremisia sieberi Besser is a widely distributed plant that grows in many areas of Iran and has strong insecticidal activity against stored product pests, so an experiment was conducted to investigate fumigant toxicity of the A. sieberi oil collected from Karaj region of Iran. The oil was applied against one to seven day old adults of three major stored product insects including: Callosobruchus maculatus (Fab.), Sitophilus oryzae (L.), and Tribollium castaneum (Herbst). The potency of fumigant toxicity of A. sieberi on C. maculatus was higher (LC₅₀: 1.64 μL per L) than S. oryzae (LC₅₀: 4.41 μL per L) and T. castaneum (LC50: 20.31 μ.L per L). The relationships between the time exposure and oil concentration on mortality show that the mortality was increased as oil concentration and exposure time was increased. The concentration of 185 μL per L and exposure time of 24h was enough to obtain 100% kill of the insects. It was also found that the regions where A. sieberi grows affect essential oil components of the plant and can play an important role in properties of fumigant toxicity.     

Fumigant toxicity of essential oil of Mugwort (Artemisia vulgaris L.) against three major stored product beetles

Application of plants essential oil for the evaluation of their fumigant toxicity and insecticidal properties is the goal of many researches. In this study, aerial parts of Artemisia vulgaris L. were subjected to hydrodistillation using a Clevenger-type apparatus, and the chemical composition of the volatile oils was studied by gas chromatography–mass spectrometry. Alpha-Pinene (23.56) was the main component of the essential oil. Insecticidal activity of the oil was evaluated against Tribolium castaneum (Herbst), Callosobruchus maculatus (F.) and Rhizopertha dominica (F.) after 24, 48 and 72 h. After 24-h exposure time, C. maculatus was more susceptible (LC₅₀ = 52.47 μl/l air) and T. castaneum was more tolerant (LC₅₀ = 279.86 μl/l air) than other species. LT₅₀ values were indicated using highest concentration of LC₅₀ tests for three species. In general, mortality increased as the doses of essential oil and exposure time increased. These results proposed that A. vulgaris oil might have potential as a control agent against T. castaneum, R. dominica and especially C. maculates in storages.     

Schistosomicidal Effects of the Essential Oils of Citrus limonia and Citrus reticulata Against Schistosoma mansoni

We report the in vitro schistosomicidal effects of the essential oil obtained from Citrus limonia leaves (CL ‐EO ) and C. reticulata fruit peels (CR ‐EO ), cultivated in Brazil, against Schistosoma mansoni worms. Limonene (29.9%), β ‐pinene (12.0%), sabinene (9.0%), citronellal (9.0%), and citronellol (5.8%) are the major constituents of CL ‐EO ; limonene (26.5%), γ ‐terpinene (17.2%), linalool (11.1%), octanal (8.0%), myrcene (6.2%), and capraldehyde (3.9%) predominate in CR ‐EO . CL ‐EO displayed moderate lethal concentration 50% (LC ₅₀) of 81.7 and 38.9 μg/ml against male and female worms at 24 and 72 h, respectively. At concentrations of 25 and 100 μg/ml, CL ‐EO separated between 50 and 75% of the coupled worm pairs during the evaluated period. CR ‐EO presented moderate LC ₅₀ of 81.7 μg/ml against male and female worms at 24 and 72 h. However, this oil separated coupled worm pairs more effectively than CL ‐EO and displayed lower cytotoxicity to GM 07492‐A cells (IC ₅₀ = 987.7 ± 88.9 μg/ml) as compared to CL ‐EO (IC ₅₀ = 187.8 ± 2.9 μg/ml). The enantiomers (+)‐(R )‐limonene and (?)‐(S )‐limonene did not affect S. mansoni adult worm pairs significantly. Taken together, these data indicate that CL ‐EO and CR ‐EO exhibit moderate in vitro schistosomicidal activity against adult S. mansoni worms.     

Adverse Effect of Essential Oil Fumigation on Proisotoma minuta (Collembola: Entomobryoidae)

Eighteen essential oils were tested for their fumigant toxicity towards Proisotoma minuta (Tullberg). The essential oils of citronella (LD₅₀=0.65 μL/L air), petitgrain (LD₅₀=2.3 μL/L air), and thyme (LD₅₀=2.8 μI/L air) produced potent activity towards the species.     

Fumigant Toxicity of Plant Essential Oils to Plutella xylostella (Lepidoptera: Yponomeutidae) and Cotesia glomerata (Hymenoptera: Braconidae)

The fumigant toxicity of 66 plant essential oils to Plutella xylostella (L.) larvae and Cotesia glomerata (L.) adults was examined using a vapor-phase toxicity bioassay and compared with that of dichlorvos. Responses varied according to oil and insect species used. Based on 24 h LD₅₀ values, pennyroyal oil [10.77 mg/filter paper (4.25 cm diameter)] was the most toxic fumigant, followed by rosemary and sage (Dalmatin) oils (15.15 mg/paper). Potent fumigant toxicity was also produced from armoise, buchu leaf, cedarleaf, coriander, eucalyptus, howood, lavender, myrtle, niaouli, peppermint, and rosewood oils (LD₅₀, 21.29–27.31 mg/paper). All essential oils were less effective than dichlorvos (LD₅₀, 0.52 mg/paper). Against adult C. glomerata, dichlorvos (LD₅₀, 0.03 mg/paper) was the most toxic fumigant, whereas the LD₅₀ values of the 14 essential oils ranged from 1.59 to 8.51 mg/paper. Based on selective toxicity ratio (STR, P. xylostella LD₅₀/C. glomerata LD₅₀), the 14 essential oils (STR, 2.5–14.5) are more selective than dichlorvos (STR, 17.3). The essential oils tested merit further study as potential fumigants for the control of P. xylostella in greenhouses because of their selective toxicity to adult C. glomerata and their much greater activity as a fumigant.     

Bioefficacy of plant essential oils against pulse beetles Callosobruchus spp. (Coleoptera: Bruchidae) in pigeon pea seeds with particular reference to Clausena pentaphylla (Roxb.) DC.

Thirty essential oils from higher plants of Gorakhpur Division (India) were evaluated at 0.36?μl/ml against two pulse beetles, Callosobruchus chinensis L. and C. maculatus F., causing infestation of pigeon pea seeds during storage. Clausena pentaphylla oil was more effective and exhibited absolute repellency against both the insects followed by Ocimum canum, Salvia plebeia and Zingiber zerumbet oils. Among these four oils, C. pentaphylla oil was most toxic and showed 100% mortality of both the insects at 10-μl dosage and 24-h exposure (LD₅₀?=?2.7?μl for C. chinensis & 2.4?μl for C. maculatus). Physical factors, viz. temperature, storage and autoclaving, did not cause any adverse effect on the toxicity of Clausena oil. During in vivo investigation, the oil protected 1?kg of pigeon pea seeds completely without reducing weight loss and seed damage up to 6?months when stored in gunny bags and glass containers. The oil was standardised by determining its various physicochemical properties. Thus, C. pentaphylla oil can be judiciously exploited as herbal insecticide against pulse beetles of pigeon pea seeds during storage.     

Acute toxicity of kaolin and essential oils from Mentha pulegium and Zingiber officinale against different stages of Callosobruchus maculatus under laboratory conditions

Naturally derived compounds such as essential oils and natural mineral are relatively cheap, non-toxic to food grains and environmentally friendly and would be suitable alternatives for currently used chemical insecticides if they have high insecticidal effectiveness. In the present study, acute toxicity of kaolin and essential oils from Mentha pulegium and Zingiber officinale were assessed on different stages of Callosobruchus maculatus at 28?±?2?°C, 65?±?5% R. H and dark condition. The calculated LC₅₀ values on the egg, larvae and adult stages of C. maculatus were 1.15, 2.33 and 2.18?μl/ml air for Z. officinale and 0.07, 0.11 and 0.09?μl/ml air for M. pulegium, respectively. The result showed that M. pulegium was more effective essential oil against different stages of C. maculatus compared with the Z. officinale, and also the egg and adult stages of C. maculatus were more susceptible against essential oils compared with larval stage. The LC₅₀ values of kaolin were 0.71 and 0.18?mg/cm² on egg and adult of C. maculatus, respectively. The combination of tested essential oils with kaolin increased mortality of C. maculatus adults compared with their application alone. It was found that tested essential oils and kaolin had high potential in controlling different stages of C. maculatus.     

Chemical Composition and Antioxidant,Antiparasitic, Cytotoxicity and Antimicrobial Potential of the Algerian Limonium Oleifolium Mill. Essential Oil and Organic Extracts

This work aimed to investigate, for the first time, the chemical composition, antioxidant, antiparasitic, cytotoxicity, and antimicrobial activities of the aromatic plant Limonium oleifolium Mill. essential oil (EO) and organic extracts. L. oleifolium aerial parts essential oil was analyzed by GC-FID and GC-MS, and 46 constituents representing 98.25±1.12 % of the oil were identified. γ-Muurolene (10.81±0.07 %), cis-caryophyllene (7.71±0.06 %), o-cymene (7.07±0.01 %) and α-copaene (5.02±0.05 %) were the essential oil main compounds. The antioxidant activity of L. oleifolium EO and organic extracts (MeOH, CHCl₃, AcOEt, BuOH) was explored using 2,2-diphenyl-1-picrylhydrazyl (DPPH), ABTS, β-carotene/linoleic acid, cupric reducing antioxidant capacity (CUPRAC), and ferric reducing power assays. The results showed that L. oleifolium EO exhibit antioxidant capacity (IC₅₀=17.40±1.32 μg/mL for DPPH assay, IC₅₀=29.82±1.08 μg/mL for β-carotene assay, IC₅₀=25.23±1.01 μg/mL for ABTS assay, IC₅₀=9.11±0.08 μg/mL for CUPRAC assay and IC₅₀=19.41±2.06 mg/mL for reducing power assay). Additionally, the EO showed significant activity against trophozoite form of Acanthamoeba castellanii (IC₅₀=7.48±0.41 μg/mL) and promastigote form of Leishmania amazonensis (IC₅₀=19.36±1.06 μg/mL) and low cytotoxicity on murine macrophages (LC₅₀ 90.23±1.09 μg/mL), as well as good antimicrobial activity against Staphylococcus aureus, Escherichia coli, Klebsiella oxytoca, and Pseudomonas aeruginosa. These results suggest that L. oleifolium essential oil is a valuable source of bioactive compounds presenting antioxidant, antiparasitic, and antimicrobial activities. Furthermore, it is considered nontoxic.     

Insecticidal Activity and Chemical Composition of the Essential Oils of Artemisia lavandulaefolia and Artemisia sieversiana from China

In our screening program for new agrochemicals from local wild plants, Artemisia lavandulaefolia and A. sieversiana were found to possess insecticidal activity against the maize weevil Sitophilus zeamais. The essential oils of the aerial parts of the two plants were obtained by hydrodistillation and analyzed by GC and GC/MS. The main components of A. lavandulaefolia oil were caryophyllene (15.5%), β‐thujone (13.8%), eucalyptol (13.1%), and β‐farnesene (12.3%), and the principal compounds identified in A. sieversiana oil were eucalyptol (9.2%), geranyl butyrate (9.2%), borneol (7.9%), and camphor (7.9%). The essential oils of A. lavandulaefolia and A. sieversiana possessed fumigant toxicity against S. zeamais adults with LC₅₀ values of 11.2 and 15.0 mg/l air, respectively. Both essential oils also showed contact toxicity against S. zeamais adults with LD₅₀ values of 55.2 and 112.7 μg/adult, respectively.     

Toxic and deterrent effects of two volatile oils against cowpea weevil,Callosobruchus chinensis (Coleoptera: Bruchidae)

The fumigant effect of Mentha piperita and Ocimum basilicum oils and their mixture against adults and eggs of Callosobruchus chinensis (L.) was evaluated. Bioassay experiments showed that Ocimum basilicum oil was significantly effective against adult and egg stage which was the least effective. However, in the fumigant toxicity experiments against adult stage, Ocimum basilicum oil at a dose of 1.0 μl/38.5 ml air caused 100% mortality (LC₅₀ = 1.88), the mixture of both oils at a dose of 6.0 μl/38.5 ml air caused 100% mortality (LC₅₀ = 10.3) and Mentha piperita oil at a dose of 80.0 μl/38.5 ml air caused 80.0% mortality (LC₅₀ = 41.224) during a one day exposure period. Regarding the oviposition deterrent activity, Ocimum basilicum oil achieved 100% oviposition deterrent (at a dose of 0.5 μl/38.5 ml air) followed by the mixture of Mentha piperita and Ocimum basilicum oils, which achieved 71.22% oviposition deterrent (at a dose of 1.0 μl/38.5 ml air) and Mentha piperita oil, which achieved 39.6% oviposition deterrent (at a dose of 5.0 μl/38.5 ml air). The essential oils and their mixtures studied here determined a significant decrease in the number of eggs hatched and in the emergence of adults. The eggs failed to hatch on using Ocimum basilicum oil at a dose of 0.6 μl/38.5 ml air. However, the number of eggs hatched decreased to 7.4 on using a mixture of oils at a dose of 2.0 μl/38.5 ml air and 14.0 with Mentha piperita oil at a dose of 80.0 μl/38.5 ml air compared with 25.0 eggs hatched in the control experiments. On the other hand, the percentage reduction in emerging adults were 100% for Ocimum basilicum oil, 90.9% for a mixture of the two oils and 72.7% for Mentha piperita oil. Results showed that Ocimum basilicum oil and Ocimum basilicum oils plus Mentha piperita oils in blend are potential alternatives to synthetic fumigants in the treatment of durable agricultural products. Successful adoption of plant oils in the protection of food commodities promises an eco-friendly option compatible with international biosafety regulations.     

Antibiofilm Activity of Invasive Plants against Candida albicans: Focus on Baccharis halimifolia Essential Oil and Its Compounds

The extracts of five invasive plants were investigated for antifungal and antibiofilm activities against Candida albicans, C. glabrata, C. krusei, and C. parapsilosis. The antifungal activity was evaluated using the microdilution assay and the antibiofilm effect by measurement of the metabolic activity. Ethanol and ethanol-water extracts of Reynoutria japonica leaves inhibited 50 % of planktonic cells at 250 μg mL⁻¹ and 15.6 μg mL⁻¹, respectively. Ethanol and ethanol-water extracts of Baccharis halimifolia inhibited >75 % of the mature biofilm of C. albicans at 500 μg mL⁻¹. The essential oil (EO) of B. halimifolia leaves was the most active (50 % inhibition (IC₅₀) at 4 and 74 μg mL⁻¹against the maturation phase and 24 h old-biofilms of C. albicans, respectively). Oxygenated sesquiterpenes were the primary contents in this EO (62.02 %), with β-caryophyllene oxide as the major component (37 %). Aromadendrene oxide-(2), β-caryophyllene oxide, and (±)-β-pinene displayed significant activities against the maturation phase (IC₅₀=9–310 μ mol l⁻¹) and preformed 24 h-biofilm (IC₅₀=38–630 μ mol l⁻¹) of C. albicans with very low cytotoxicity for the first two compounds. C. albicans remained the most susceptible species to this EO and its components. This study highlighted for the first time the antibiofilm potential of B. halimifolia, its EO and some of its components.     

Control of stored grain pest,Callosobruchus maculatus (F.) (Coleoptera: Bruchidae), using the essential oils isolated from Zingiber officinale (L.) and Mentha pulegium (L.) in laboratory condition

Fumigant activity of essential oil vapours distilled from Zingiber officinale (L.) and Mentha pulegium (L.) was tested against eggs, larvae and adults of Callosobruchus maculatus (F.). Fumigant toxicity was assessed at 27?±?1?°C and 60?±?5% RH, in dark condition. The influence of different concentrations of the essential oil vapours on egg hatchability, larval and adult mortality was significant. Data probit analysis showed that lethal concentration of the essential oil to kill 50% of the population (LC₅₀) for egg, larvae and adult was found to be 1.151, 2.336 and 2.183?μl/l air of Z. officinale, followed by 0.072, 0.113 and 0.093?μl/l air essential oil of M. pulegium, respectively. Between these essential oils, Z. officinale is almost more toxic than M. pulegium on all growth stages of C. maculatus. The present study suggests that essential oils from these medicinal plants may be potential grain protectants as botanical alternative fumigants and could be used in the management of various life stages of C. maculatus.     

Chemical Composition and Insecticidal Activity of Artemisia scoparia Essential Oil against Three Coleopteran Stored-Product Insects

Chemical composition of the essential oil from Artemisia scoparia Waldst et Kit, and its fumigant and repellent activity were investigated against three stored product insects, Callosobruchus maculatus (Fab.), Sitophilus oryzae (L.), and Tribolium castaneum (Herbst). Dry ground leaves were subjected to hydrodistillation using a modified clevenger-type apparatus and the chemical composition of the volatile oil was studied by GC-MS. Nineteen components (99.51% of the total composition) were identified. β-Pinene (19.01%), capillin (17.45%), limonene (15.11%), myrcene (10.95) were found to be the major constituents of the oil. The mortality of 1-7 day old adults of the insect pests increased with concentration from 37 to 926 μL per L air and with exposure time from 3 to 24 h. A concentration of 37 μL per L air and exposure time of 24 h was sufficient to obtain 100% kill of the insects. Callosobruchus maculatus was more susceptible than S. oryzae and T. castaneum. A second more detailed bioassay gave estimates for the LC₅₀ of C. maculatus as 1.46 μL per L air, S. oryzae 1.87 μL per L air and T. castaneum 2.05 μL per L air. Also, the essential oil was significantly more repellent to T. castaneum and S. oryzae than C. maculatus. However, half-life time of the oil for C. maculatus was longer than S. oryzae and T. castaneum. These results show the efficacy of A. scoparia oil for use in organic food protection.     

Analysis of the chemical composition of root essential oil from Indian sarsaparilla (Hemidesmus indicus) and its application as an ecofriendly insecticide and pharmacological agent

The Indian sarsaparilla (Hemidesmus indicus) is a commonly used plant in Indian traditional medicine of Ayurveda for the preparation of various non-alcoholic beverages. However, limited studies are available on the essential oil of H. indicus roots (HRO); therefore, the study evaluated the antioxidant, anti-inflammatory and antidiabetic activities of H. indicus root essential oil as well as insecticide potential against the common pests of stored food materials (Sitophilus oryzae, Callosobruchus maculatus and Tribolium castaneum). The repellant efficacy of HRO was found to be high against S. oryzae (8.21 ± 0.55 μg/mL). Likewise, the fumigant potential was also observed for HRO against these pests; the higher activities were observed against S. oryzae and C. maculatus (32.46 ± 1.42 and 35.18 ± 1.62 μg/L). Besides, the essential oil was also found to be active as a contact poison, however, against all the three pests, the toxicity was above 100 μg/mm³, being the highest against C. maculatus (122.8 ± 3.57 μg/mm³). To analyze the possible effect of the essential oil on grains, the different grains were allowed to germinate and compared to that of normal; thus, the non-toxic nature of HRO against the stored products is also confirmed. The essential oil shown to have DPPH hydrogen peroxide and ABTS radical scavenging, nitric oxide scavenging potential, and inhibition of lipoxgenase, alpha-amylase and alpha-glucosidase. Overall, the present study concludes that the H. indicus may be a suitable repellant and fumigant agent against different pests of stored products and a possible antioxidant, anti-inflammatory, and anti-diabetic agent.     

Chemical Composition of the Essential Oil of Nigeria Grown Hoslundia opposita Vahl (Lamiaceae) Dried Leaves and Its Bioactivity against Cowpea Seed Bruchid

Due to several ecological and human hazards of synthetic pesticides in postharvest crop protection, there is the need to search for eco‐friendly alternatives. In this study, chemical composition and insecticidal activities of essential oil (EO) obtained from Hoslundia opposita dried leaves were evaluated against cowpea seed bruchid. Eight constituents, predominated by oxygenated monoterpenes (78.86%), were identified using Gas Chromatography (GC)/MS. The constituents were 1,8‐cineole ( 1 ; 61.15%), followed by α‐terpineol ( 2 ; 16.81%), β‐phellandrene ( 3 ; 13.24%), β‐farnesene (4; 3.55%), α‐pinene ( 5 ; 1.89%), Germacrene D ( 6 ; 1.83%), cis‐sabinene hydrate ( 7 ; 0.90%) and caryophyllene ( 8 ; 0.63%). In fumigation bioassay, at 6 h after exposure (HAE), 0.78 ml EO/l air caused 35.33% mortality which was significantly lower than 60.90% and 63.6% observed at 3.15 and 6.25 ml/l air, respectively. Mortality reached 90.0% at 24 HAE regardless of the applied concentration. Lethal time for 50% of the bruchids (LT₅₀) at concentration of 0.78 ml/l air (6.89 h) was higher than the LT₅₀ at 3.15 and 6.25 ml/l air (4.72 and 4.44 h, respectively). H. opposita EO reduced Callosobruchus maculatus oviposition, while progeny emergence observed in EO‐treated seeds (2.42 – 25.73) was significantly (P < 0.05) lower than 51.56 observed in control. The results confirm H. opposita EO's potentials for control of cowpea bruchids.     

Investigation on the insecticidal efficacy of novel pellet formulation against Callosobruchus maculatus (F.) (Col.: Bruchidae) in three different heights and compared with phosphine

Applying essential oils, fumigant toxicity in stored products pests control has sharpened recently. Since these products have low penetration power and vapour pressure, their use in crop depth is restricted. The aim of this work was using controlled release technology to solve this problem. In this research, 1,8-cineole-based pellets were prepared by dry mixing method and physical load of 1,8-cineole on strach, which followed by pressing the mixture, using pellet maker apparatus, to form pellets. Insecticidal efficacy of produced pellets was investigated against adults (1–3?days old) Callosobruchus maculatus F. (Col.: Bruchidae) compared with phostoxin under 28?±?2?°C and darkness in laboratory condition. LC₅₀ and LC₉₅ of pellets against C. maculatus in 24?h were 0/017 and 0/050?ml active ingredient per L air, respectively. LC₅₀ and LC₉₅ of phosphine pellets against C. maculatus in 24?h were 0/124 and 1/852?ml active ingredient per L air, respectively.     

Chemical Constituents and Activities of the Essential Oil from Myristica fragrans against Cigarette Beetle Lasioderma serricorne

Essential oil extracted from nutmeg seeds (Myristica fragrans Houtt .) by hydrodistillation was subjected to GC/MS and GC analysis. A total of 27 constituents were identified, of which eugenol (19.9%), methylisoeugenol (16.8%), methyleugenol (16.7%), sabinene (11.8%), and terpinen‐4‐ol (8.5%) were the major components. The essential oil was tested against Lasioderma serricorne for insecticidal and repellent activity, the LD₅₀ value at the end of 24 h exposure period was 19.3 μg/adult. Six active compounds were isolated by bioassay‐guided fractionation. They were identified as eugenol ( 1 ), methyleugenol ( 2 ), methylisoeugenol ( 3 ), elemicin ( 4 ), myristicin ( 5 ), and safrole ( 6 ). Among these isolates, 4 showed the strongest contact toxicity against L. serricorne adults with an LD₅₀ value of 9.8 μg/adult. Repellency of crude oil and active compounds were also determined. Compounds 1, 2, 4 , and 5 were strongly repellent against the cigarette beetle and exhibited the same level of repellency compared with the positive control, DEET. The results indicate that the essential oil of M. fragrans and its active constituents have potential for development as natural insecticides and repellents to control L. serricorne.     

Evaluation of insecticidal activity of the essential oil of Allium chinense G. Don and its major constituents against Liposcelis bostrychophila Badonnel

Water-distilled essential oil from the dried bulbs of Allium chinense (Liliaceae) was analyzed by gas chromatography–mass spectrometry (GC–MS). Eighteen compounds, accounting for 98.4% of the total oil, were identified and the main components of the essential oil of A. chinense were methyl allyl trisulfide (30.7%), dimethyl trisulfide (24.1%), methyl propyl disulfide (12.8%) and dimethyl disulfide (9.6%) followed by methyl allyl disulfide (3.4%) and methyl propyl trisulfide (3.6%). The essential oil exhibited contact toxicity against the booklice (Liposcelis bostrychophila) with an LC₅₀ value of 441.8 μg/cm² while the two major constituents, dimethyl trisulfide and methyl propyl disulfide had LC₅₀ values of 153.0 μg/cm² and 738.0 μg/cm² against the booklice, respectively. The essential oil of A. chinense possessed strong fumigant toxicity against the booklice with an LC₅₀ value of 186.5 μg/l while methyl allyl trisulfide (LC₅₀ = 90.4 μg/l) and dimethyl trisulfide (LC₅₀ = 114.2 μg/l) exhibited stronger fumigant toxicity than methyl propyl disulfide (LC₅₀ = 243.4 μg/l) and dimethyl disulfide (LC₅₀ = 340.8 μg/l) against the booklice. The results indicated that the essential oil and its major constituents have potential for development into natural insecticides or fumigants for control of insects in stored grains.