A clinical case of anaphylaxis after eating oatmeal contaminated with booklice (Liposcelis bostrychophila).

A 52-year-old man presented to our department with generalized erythema, watery stools, and vomiting 30 min after ingesting coconut, oatmeal, and vegetable juice. On arrival, his blood pressure was 120/79 mm Hg, heart rate was 126 beats per min, blood oxygen saturation was 96%, and lip cyanosis was observed. The patient experienced diffuse redness throughout the body and was diagnosed as having severe anaphylaxis. A skin prick test for the leftover coconut, oatmeal, and vegetable juice, which the patient had consumed immediately before the onset of symptoms, showed a positive reaction only to the leftover oatmeal. Direct microscopic examination of the leftover oatmeal revealed numerous insect bodies that appeared as booklice. Using Western blot analysis and quantitative polymerase chain reaction, Lip b 1, a specific antigen for Liposcelis bostrychophila (badonnel), an indoor pest that inhabits various places and feeds on various indoor materials, including stored foods, was detected only in the extract of the leftover oatmeal. Based on these results, we identified an insect body infesting oatmeal, L. bostrychophila. The serum level of L. bostrychophila-specific immunoglobulin antibodies was higher than the cutoff value; therefore, we identified the disease as anaphylaxis caused by accidental ingestion of L. bostrychophila that infested the oatmeal stored in the container. We report the first case of L. bostrychophila-infested oatmeal as an orally ingested allergen in Japan.

The essential oil of Kochia scoparia (L.) Schrad. as a potential repellent against stored-product insects.

Chemical composition of the essential oil from Kochia scoparia (L.) Schrad. (syn. Bassia scoparia (L.) A. J. Scott) was analyzed in quality and quantity by GC-MS and GC-FID. Repellent activities of the essential oil from K. scoparia (KSEO) were evaluated against two common species of stored-product insects Tribolium castaneum Herbst and Liposcelis bostrychophila Badonnel. Results indicated that KSEO mainly consisted of eugenol, ß-caryophyllene, and α-humulene, accounting for 75.6%, 8.2%, and 1.4% of the total oil, respectively. KSEO and the three major components were repellent to T. castaneum and L. bostrychophila adults. Notably, KSEO exerted significant effects, comparable to the positive control DEET at 2 and 4 h post-exposure. Eugenol at 63.17-2.53 nL/cm2 exhibited high percentage repellency ranging from 96 to 70% against L. bostrychophila during 4-h exposure. To gain further insights into the repellent activity, molecular docking simulation was performed with eugenol as the ligand and an odorant binding protein TcOBPC12 (gene: TcOBP10B) from the model insect T. castaneum as the receptor. Docking calculation results revealed that TcOBPC12 had binding affinity to eugenol (△G = - 4.52 kcal/mol) along with a hydrogen bond of 0.18 nm (1.8 Å) long forming between them, which could be an important target protein associated with identifying volatile repellent molecules. This work highlights the promising potential of KSEO as a botanical repellent for controlling stored-product insects.

Essential Oils from Different Parts of Magnolia laevifolia: Chemical Constituents and Insecticidal Activities against Liposcelis bostrychophila.

Many synthetic pesticides were used to control a severe storage pest, booklouse (Liposcelis bostrychophila). However, considering the environmental impact, plant secondary metabolites were acceptable alternatives. An endemic plant, Magnolia laevifolia, has a significant and unique odour, so its essential oil (EO) could be an option for bio-pesticide development. This study extracted EOs from leaves, flowers, carpels and seeds of M. laevifolia. The common and major compound of EOs was isocapnell-9-en-8-one, which was present at 17.7 to 91.6 % in these four parts. We found no regular pattern in the composition of EO in terms of parts and collection time according to principal component analysis. The contact and repellent activities of EOs against the booklouse were then conducted. Leaves and flowers' EOs collected in the flowering stage had the best contact toxicity. The percent repellency values of the EOs from different parts of M. laevifolia reached above 80 % after 2 and 4 h exposure at 63.17 nL/cm2 , with the same levels as DEET (p<0.05). It was shown that parts of plants and collecting time could influence the insecticidal activities of M. laevifolia EOs against booklouse, but collecting time played a significant decisive role in the contact test.

An advanced approach for rapid visual identification of Liposcelis bostrychophila (Psocoptera: Liposcelididae) based on CRISPR/Cas12a combined with RPA.

Liposcelis bostrychophila Badonnel (Psocoptera: Liposcelididae) is a booklouse pest that is a threat to commodity storage security worldwide. Accurate and sensitive methods of L. bostrychophila on-site identification are essential prerequisites for its effective management. Evidence suggests that L. bostrychophila contains 3 intraspecific biotypes that are morphologically indistinguishable but can be discriminated at the level of mitochondrial genome organization and sequences. The traditional molecular identification methods, such as DNA barcoding and PCR-RFLP, are instrumentally demanding and time-consuming, limiting the application of the identification in the field. Therefore, this study developed a new CRISPR/Cas12a-based visual nucleic acid system based on the mitochondrial gene coding for NADH dehydrogenase subunit 2 (nad2), combined with recombinase polymerase amplification (RPA) to accurately identify L. bostrychophila from 4 other common stored-product booklice, and also differentiate 3 biotypes of this species at the same time. The entire identification process could be completed at 37 °C within 20 min with high sensitivity. The system could stably detect at least 1 ng/µl of DNA template. The green fluorescence signal produced by the trans-cleaving of the single-stranded DNA reporter could be observed by the naked eye under blue light. Additionally, the suggested system combined with the crude DNA extraction method to extract DNA rapidly, enabled identification of all developmental stages of L. bostrychophila. With crude DNA, this novel diagnostic system successfully identified an unknown booklouse by holding the reaction tubes in the hand, thus can be considered as an accurate, rapid, highly sensitive, and instrument-flexible method for on-site visual identification of L. bostrychophila.

Chemical Diversity and Anti-Insect Activity Evaluation of Essential Oils Extracted from Five Artemisia Species.

As a source of aromatic plants, the genus Artemisia has long been considered to have the potential to develop plant pesticides. In this study, components of essential oils from A. dalai-lamae, A. tangutica, A. sieversiana, A. tanacetifolia and A. ordosica were identified by GC-MS. A total of 56 constituents were analysed, and each species consisted of 9 to 24 constituents. Principle component analysis (PCA) revealed that A. dalai-lamae, A. tangutica and A. tanacetifolia are characterised by monoterpene hydrocarbons and oxygenated monoterpenes. Hierarchical cluster analysis (HCA) showed the most remarkable similarity between A. sieversiana and A. ordosica, but the similarity was still lower than 50%. Contact toxicity and repellency of essential oils were evaluated by bioassays; A. ordosica oil exhibited the most substantial contact toxicity (LD50 = 52.11 µg/cm2) against Liposcelis bostrychophila, while A. tangutica oil showed the most potent contact toxicity (LD50 = 17.42 µg/adult) against Tribolium castaneum. Except for A. dalai-lamae, the other four species showed the same level (p > 0.05) of repellent activity as the positive control against both pests at high concentrations. The results indicated that these five Artemisia species had high chemical diversity and great potential to be developed into more effective and environmentally friendly anti-insect agents.

Booklice Liposcelis bostrychophila Naturally Infected by Rickettsia felis Cause Fever and Experimental Pneumonia in Mammals.

BACKGROUND: Rickettsia felis is emergent in tropical areas. Despite its high morbidity, its natural history has not yet been fully determined. We investigated the role of the common household booklouse, Liposcelis bostrychophila, recently found to harbor R. felis. METHODS: Blood samples from 372 febrile patients from Senegalese villages, as well as nasal and skin samples from 264 asymptomatic individuals, were tested for cat flea-associated and booklice-associated strains of R. felis. Dust samples from beds were collected to isolate booklice and R. felis. Mice were infected with aerosol of R. felis strain from naturally infected booklice. RESULTS: Forty febrile patients (11%) were infected by R. felis, including 26 (7%) by the booklice-associated strain. Nine nasal samples (3.4%) and 28 skin samples (10.6%) contained R. felis, including 7 and 24, respectively, with the booklice-associated strain. The presence of live L. bostrychophila was observed in 32 dust samples (16.8%); R. felis was identified in 62 dust samples (32.5%). Several mice samples were positive for R. felis; interstitial lymphohistiocytic infiltrates were identified in lungs. CONCLUSIONS: Liposcelis bostrychophila may be a reservoir of R. felis. The booklice-associated strain is pathogenic in mammals, causing pneumonia. Human infection may be acquired via inhalation of infected booklice particles.

Sesquiterpenoid-rich Essential Oils from Two Magnolia Plants: Contact and Repellent Activity to Three Stored-product Insects.

Stored products have been damaged by insects. Multiple approaches for pest management are employed. Among these approaches, botanical insecticide is an emerging one. This work investigated the pest management potential of Magnolia coriacea and Magnolia macclurei essential oils (EOs) to three major stored-product insects, namely the red flour beetle, cigarette beetle and booklouse. Magnolia coriacea and M. macclurei EOs showed promising contact toxicity to the cigarette beetle, with LD50 values of 11.7 and 12.3 µg/adult. The contact toxicity of M. coriacea EOs to the booklouse (LC50 = 95.5 µg/cm2) was much stronger than that of M. macclurei EOs (LC50 = 245.4 µg/cm2). To explore the contribution of individual compounds to insecticidal activity of EOs, chemical analysis was performed by GC-MS. Results showed that nerolidol (27.84%), agarospirol (18.34%), elixene (15.84%) and helminthogermacrene (12.69%) were major compounds of M. coriacea EOs, ß-guaiene (60.31%) and elixene (20.42%) dominated in M. macclurei EOs. Nerolidol and ß-guaiene showed contact activity to three insect species. Nerolidol showed stronger contact toxicity to the red flour beetle and cigarette beetle than M. coriacea EOs did, both samples were similar to the booklouse. ß-Guaiene was much stronger to the red flour beetle and booklouse, but weaker to the cigarette beetle than M. macclurei EOs did. The repellent effects of EOs and compounds were at various levels. Generally, results suggested that the contact toxic potential of samples could serve as management for the cigarette beetle and booklouse, while repellent effect would be used to control the red flour beetle.

Insecticidal and Repellent Activity of Thymus quinquecostatus Celak. Essential Oil and Major Compositions against Three Stored-Product Insects.

Thymus quinquecostatus Celak. of the Lamiaceae family has a long history of dual use of medicine and food with high economic value, and has been proved to have good antioxidative, antimicrobial, and antidiabetic activities. Essential oil (EO) extracted from the aerial part of T. quinquecostatus was obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC/MS) and GC. Totally 45 compounds were identified accounting for 98.5 % of the EO. The major constituents of the EO were linalool (52.003 %), borneol (10.911 %) and anethole (5.325 %). Fumigant, contact and repellent activity of T. quinquecostatus essential oil (EO) against Tribolium castaneum (Coleoptera: Tenebrionidae), Lasioderma Serricorne (Coleoptera: Anobiidae), Liposcelis bostrychophila (Psocoptera: Liposcelididae) were evaluated in this work. T. quinquecostatus EO and three major constituents showed varying degrees of insecticidal and repellent activities to three stored-product insects. Anethole stated the best fumigant and contact activity than others did to all three insect species. EO and compounds showed general repellent activity against three target insects. This work suggests that the EO of T. quinquecostatus has promising potential to be developed into botanical pesticides and repellents controlling pest damage in warehouses and grain stores.

Chemical compositions and repellent activity of Clerodendrum bungei Steud. essential oil against three stored product insects.

BACKGROUND: Several species of Verbenaceae have been widely used in medicine, and some species of Verbenaceae have been observed good insecticidal activity, such as Lantana camara and Vitex negundo. There is no report about repellent activity of Clerodendrum bungei Steud. (C. bungei) against stored product insects. The chemical composition of C. bungei essential oil (EO) were identified, repellent activity of methanol extract, EO of C. bungei and two main components of EO against T. castaneum, L. serricorne and L. bostrychophila were evaluated for the first time. RESULTS: EO of C. bungei was obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS) and GC. A total of 25 components of the C. bungei EO were identified. The principal compounds in the EO were myristicin (75.0%), 2,2,7,7-Tetramethyltricyclo[6.2.1.0(1,6)]undec-4-en-3-one (4.1%) and linalool (3.4%). Results of bioassays indicated that C. bungei EO exerted strong repellent activity against three target insects. As main constituents, myristicin and linalool also had certain repellency. CONCLUSION: This work suggests that the EO of C. bungei has promising potential to develop into botanical repellents for the control of pest damage in warehouses and grain stores.

Comparative analysis on bioactivity against three stored insects of Ligusticum pteridophyllum Franch. rhizomes essential oil and supercritical fluid (SFE-CO2) extract.

In order to develop more environmentally benignant insecticides, the Ligusticum pteridophyllum Franch. rhizomes essential oil and supercritical fluid (SFE-CO2) extract were obtained by two published techniques, hydrodistillation and SFE-CO2. The chemical components of this two tested samples were identified by using gas chromatography-mass spectrometry (GC-MS) and gas chromatography-flame ionization detector (GC-FID). Repellent activity and contact toxicity of the obtained samples and myristicin against the adults of Tribolium castaneum (Coleoptera: Tenebrionidae), Lasioderma serricorne (Coleoptera: Anobiidae), and Liposcelis bostrychophila (Psocoptera: Liposcelididae) were compared. Nineteen components were identified in the SFE-CO2 extract. Twelve components were identified in the L. pteridophyllum rhizomes essential oil. SFE-CO2 extract exhibited higher contact toxicity against T. castaneum, L. serricorne, and L. bostrychophila (LD50 = 69.60 µg/adult, 14.58 µg/adult, and 1.69 µg/cm2, respectively) than that of L. pteridophyllum rhizomes essential oil (LD50 = 87.99 µg/adult, 89.82 µg/adult, and 7.87 µg/cm2, respectively). Besides, myristicin (LD50 = 36.46 µg/adult) showed superior contact toxicity against T. castaneum than that of the L. pteridophyllum rhizomes essential oil and SFE-CO2 extract. It possessed potentially practical significance to develop L. pteridophyllum rhizomes into plant pesticide or repellent agent for these stored insect controls. Graphical abstract .

Toxicity and repellent activity of essential oil from Mentha piperita Linn. leaves and its major monoterpenoids against three stored product insects.

The essential oil (EO) from leaves of Mentha piperita was extracted by hydrodistillation. Twenty-one chemical components, accounting for 97.5% of the total oil, were determined by GC-MS and GC-FID. The major chemical components included menthol (41.6%), L-menthone (24.7%), isomenthol (6.3%), and limonene (5.0%). The bioactivity of the obtained EO and its two major components against Tribolium castaneum, Lasioderma serricorne, and Liposcelis bostrychophila adults were evaluated by fumigation, contact, and repellent activity bioassay. The EO showed significant fumigation and contact toxicity against T. castaneum (LC50 = 18.1 mg/L air and LD50 = 2.9 µg/adult, respectively), L. serricorne (LC50 = 68.4 mg/L air and LD50 = 12.6 µg/adult, respectively), and L. bostrychophila (LC50 = 0.6 mg/L air and LD50 = 49.8 µg/adult, respectively) adults. Meanwhile, the repellent effect of the EO on T. castaneum and L. serricorne adults was comparable to that of the positive control at the highest tested concentration. Menthol and L-menthone were two major components in total oil. Among them, L-menthone exhibited significant insecticidal activity on target insects, and menthol showed notable repellent effects. The results indicated that the EO of M. piperita leaves and two tested components have potential to be developed as natural insecticides and repellents for the control of stored product insect pests. Graphical abstract.

Contact toxicity and repellent efficacy of Valerianaceae spp. to three stored-product insects and synergistic interactions between two major compounds camphene and bornyl acetate.

In this work, the essential oil (EO) and supercritical CO2 fluid extract (SF extract) of four Valerianaceae plants (Valeriana officinalis L., Valeriana officinalis L. var. latifolia Miq., Valeriana jatamansi Jones and Nardostachys chinensis Bat.) were chemically characterized. GC-MS analysis identified 74 compounds, representing 35.2%-82.4% of the total EOs and SF extracts. The EO was dominated by low-molecular-weight components while the SF extract was rich in fatty acids. Bornyl acetate and camphene were the characteristic compounds in EO and SF extracts. The efficacy of six extracts against three stored-product insects was investigated. In contact assays, V. officinalis exhibited strongest toxicity to red flour beetle (LD50 = 10.0 µg/adult), and V. jatamansi EO was the most active one against the cigarette beetle (LD50 = 17.6 µg/adult), while V. officinalis var. latifolia EO showed outstanding efficacy against the booklouse (LD50 = 40.2 µg/cm2). Binary mixtures of two major compounds (camphene and bornyl acetate) were assessed for the contact toxicity to the red flour beetle. Additive effect existed in the natural proportion of V. officinalis, and synergism was observed in that of V. officinalis var. latifolia. This work confirmed the insecticidal efficacy of the species of the Valerianaceae family, and it would offer some information for the development of botanical insecticide.

Mosquito mass rearing: who's eating the eggs?

For the sterile insect technique, and other related biological control methods where large numbers of the target mosquito are reared artificially, production efficiency is key for the economic viability of the technique. Rearing success begins with high quality eggs. Excess eggs are often stockpiled and stored for longer periods of time. Any pests that prey on these eggs are detrimental to stockpiles and need to be avoided. Psocids of the genus Liposcelis (Psocoptera, Liposcelididae) are common scavengers consuming various types of organic material that are distributed globally and thrive in warm damp environments, making insectaries ideal habitats. In this short report, we investigated the species that has been found scavenging stored mosquito eggs in our insectary and identified it to be Liposcelis bostrychophila Badonnel, 1931. Additional observations were made to determine whether these predators indeed feed on mosquito eggs, and to suggest simple, effective ways of avoiding infestation.

TITLE: Élevage de masse de moustiques : mais qui mange les œufs ? ABSTRACT: Pour la technique des insectes stériles et les autres méthodes de lutte biologique associées, dans lesquelles un grand nombre de moustiques cibles sont élevés artificiellement, l'efficacité de la production est essentielle pour la viabilité économique de la technique. Le succès de l'élevage commence par des œufs de bonne qualité. Les œufs excédentaires sont souvent stockés pendant de longues périodes. Tous les organismes nuisibles qui exploitent ces œufs nuisent à ces stocks et doivent être évités. Les psoques du genre Liposcelis (Psocoptera, Liposcelididae) sont des charognards répandus qui consomment diverses matières organiques, sont répartis dans le monde entier et prospèrent dans des environnements chauds et humides, ce qui rend les insectariums des habitats idéaux pour eux. Dans ce court rapport, nous avons étudié l'espèce qui mangeait des œufs de moustiques stockés dans notre insectarium et nous avons déterminé qu'il s'agissait de Liposcelis bostrychophila Badonnel, 1931. D'autres observations ont été faites pour déterminer si ces prédateurs se nourrissent effectivement des œufs de moustiques et suggérer des moyens simples et efficaces pour éviter l'infestation.

Repellent activities of essential oils rich in sesquiterpenoids from Saussurea amara (L.) DC. and Sigesbeckia pubescens Makino against two stored-product insects.

The essential oils (EOs) from aerial parts of Saussurea amara (L.) DC. (SAEO) and Sigesbeckia pubescens Makino (SPEO) were analyzed for their chemical composition by GC-MS, and their repellent activities against adults of the red flour beetle, Tribolium castaneum Herbst, as well as the booklouse, Liposcelis bostrychophila Badonnel, were evaluated for the first time. Results of GC-MS analysis indicated that both SAEO and SPEO were characterized by high content of sesquiterpenoids (relative content > 70%) including oxygenated sesquiterpenoids. The two oil samples and their major component caryophyllene oxide exerted beneficial repellent effects on T. castaneum and L. bostrychophila at 2 and 4 h post-exposure. At 4 h post-exposure, the PR value of caryophyllene oxide could still reach 92% (class V) against T. castaneum at minimum testing concentration of 3.15 nL/cm2, and this compound was observed to result in the greatest repellency (PR = 100%) against L. bostrychophila at 12.63 nL/cm2. This work confirmed the potent repellent efficacy of SAEO and SPEO for controlling pest damage and suggested their potential to be developed into botanical repellents.

Chemical composition of essential oils from four Rhododendron species and their repellent activity against three stored-product insects.

The objective of this work was to analyze four essential oils (EOs) from Rhododendron species in China and evaluate their repellent activity against Tribolium castaneum, Lasioderma serricorne, and Liposcelis bostrychophila adults. These four EOs from Rhododendron species, including R. capitatum, R. przewalskii, R. mucronulatum, and R. micranthum, were obtained by hydrodistillation. Major components of four EOs were identified as sesquiterpenoids by GC-MS. The relatively high components included cedrene (22.20%), borneol (36.64%), 4-(2,3,4,6-tetramethylphenyl)-3-buten-2-one (27.74%), and germacrene D (27.60%). Repellent activity of EOs from Rhododendron species was investigated against T. castaneum, L. serricorne, and L. bostrychophila adults for the first time. In this study, EOs had demonstrated their repellent activities against three stored-product insects in 2- and 4-h exposure. The above results can not only provide comprehensive utilization of plant resources of Rhododendron genus but also establish a very good perspective of novel application to control stored-product insects.

Insecticidal and repellent efficacy against stored-product insects of oxygenated monoterpenes and 2-dodecanone of the essential oil from Zanthoxylum planispinum var. dintanensis.

Essential oils (EOs) extracted from leaves (EL) and fruit pericarp (EFP) of Zanthoxylum planispinum var. dintanensis were analyzed for their chemical composition by GC-MS technique and evaluated for their fumigant, contact toxicity and repellency against three stored-product insects, namely Tribolium castaneum, Lasioderma serricorne, and Liposcelis bostrychophila adults. Results of GC-MS analysis manifested that EL and EFP of Z. planispinum var. dintanensis were mainly composed of oxygenated monoterpenes. Major components included linalool, sylvestrene and terpinen-4-ol. The obvious variation observed between two oil samples was that EL contained 2-dodecanone (11.52%) in addition to the above mentioned components, while this constituent was not detected in EFP. Bioassays of insecticidal and repellent activities were performed for EL, EFP as well as some of their individual compounds (linalool, terpinen-4-ol and 2-dodecanone). Testing results indicated that EL, EFP, linalool, terpinen-4-ol and 2-dodecanone exhibited potent insecticidal and repellent activities against the three target insects selected. Among the three individual compounds, 2-dodecanone was significantly toxic to T. castaneum (LD50 = 5.21 µg/adult), L. serricorne (LD50 = 2.54 µg/adult) and L. bostrychophila (LD50 = 23.41 µg/cm2) in contact assays and had beneficial repellent effects on L. serricorne at 2 and 4 h post-exposure. The anti-insect efficacy of Z. planispinum var. dintanensis EO suggests it has potential to be used as botanical insecticide or repellent to control pest damage in warehouses and grain stores.

Efficacy of bornyl acetate and camphene from Valeriana officinalis essential oil against two storage insects.

The essential oil was extracted from the roots of Valeriana officinalis L. by hydrodistillation. The qualitative and quantitative analysis of its chemical constituents was conducted on GC-MS and GC-FID in this study. Seventeen compounds were detected and the major constituents included bornyl acetate (48.2%) and camphene (13.8%). The toxic and repellent effects of the essential oil and its two major constituents were evaluated on Liposcelis bostrychophila and Tribolium castaneum. The results of bioassays indicated that the essential oil showed the promising fumigant and contact toxicity against L. bostrychophila (LC50 = 2.8 mg/L air and LD50 = 50.9 µg/cm2, respectively) and the notable contact effect on T. castaneum (LD50 = 10.0 µg/adult). Meanwhile, the essential oil showed comparable repellent effect on T. castaneum at all testing concentrations. Bornyl acetate and camphene also exhibited strong fumigant and contact toxicity against both species of pests (LC50 = 1.1, 10.1 mg/L air and LD50 = 32.9, 701.3 µg/cm2 for L. bostrychophila; > 126.3, 4.1 mg/L air, and 66.0, 21.6 µg/adult for T. castaneum). Bornyl acetate and camphene showed moderate repellent effect on T. castaneum and conversely showed attractant effect on L. bostrychophila. This work highlights the insecticidal potential of V. officinalis, which has been noted as a traditional medicinal plant.

Evaluation of efficacy of the essential oil from Ostericum viridiflorum (Turcz.) Kitagawa in control of stored product insects.

The natural and ecologically safe control of stored product insects has gained considerable attention in modern society. In this study of further searching for botanical pesticides from wild-growing plant, the contact toxicity and repellency towards Tribolium castaneum and Liposcelis bostrychophila were assessed for the essential oil (EO) from Ostericum viridiflorum. The EO was distilled from aboveground parts of O. viridiflorum and checked by gas chromatography-mass spectrometry. Twenty-two compounds were identified and the main components were ß-caryophyllene (24.3%), α-humulene (21.0%), apiol (10.2%), and carotol (2.5%). For bioactivity tests, results indicated that the EO and its two main compounds (ß-caryophyllene and α-humulene) all showed potent contact toxicity towards L. bostrychophila with LD50 values of 44.52 µg/cm2, 74.11 µg/cm2, and 118.56 µg/cm2, respectively. The EO and the two main compounds also exhibited comparable repellency towards T. castaneum and L. bostrychophila. The results evidenced the EO of O. viridiflorum aboveground parts and its major compounds could be considered for the development of eco-friendly botanical insecticides and repellents in controlling stored product insects.

Toxic and Repellent Effects of Volatile Phenylpropenes from Asarum heterotropoides on Lasioderma serricorne and Liposcelis bostrychophila.

Toxic and repellent effects of the essential oil from Asarum heterotropoides Fr. Schmidt var. mandshuricum (Maxim.) Kitag. were evaluated against Lasioderma serricorne and Liposcelis bostrychophila. The essential oils (EOs) from roots (ER) and leaves (EL) of A. heterotropoides were obtained separately by hydrodistillation and characterized by gas chromatography-mass spectrometry (GC-MS) analysis. Major components of ER and EL included methyleugenol, safrole, and 3,5-dimethoxytoluene. Both ER and EL of A. heterotropoides showed certain toxicity and repellency against L. serricorne and L. bostrychophila. 3,5-Dimethoxytoluene, methyleugenol, and safrole were strongly toxic via fumigation to L. serricorne (LC50 = 4.99, 10.82, and 18.93 mg/L air, respectively). Safrole and 3,5-dimethoxytoluene possessed significant fumigant toxicity against L. bostrychophila (LC50 = 0.83 and 0.91 mg/L air, respectively). The three compounds all exhibited potent contact toxicity against the two insect species. Here, the EL of A. heterotropoides was confirmed to have certain toxicity and repellency against stored product insects, providing a novel idea for the comprehensive use of plant resources.

Identification of Insecticidal Constituents from the Essential Oil from the Aerial Parts Stachys riederi var. japonica.

The essential oil of Stachys riederi var. japonica (Family: Lamiaceae) was extracted by hydrodistillation and determined by GC and GC-MS. A total of 40 components were identified, representing 96.01% of the total oil composition. The major compounds in the essential oil were acetanisole (15.43%), anisole (9.43%), 1,8-cineole (8.07%), geraniol (7.89%), eugenol (4.54%), caryophyllene oxide (4.47%), caryophyllene (4.21%) and linalool (4.07%). Five active constituents (acetanisole, anisole, 1,8-cineole, eugenol and geraniol) were identified by bioactivity-directed fractionation. The essential oil possessed fumigant toxicity against maize weevils (Sitophilus zeamais) and booklice (Liposcelis bostrychophila), with LC50 values of 15.0 mg/L and 0.7 mg/L, respectively. Eugenol and anisole exhibited stronger fumigant toxicity than the oil against booklice. 1,8-Cineole showed stronger toxicity, and anisole as well as eugenol exhibited the same level of fumigant toxicity as the essential oil against maize weevils. The essential oil also exhibited contact toxicity against S. zeamais adults and L. bostrychophila, with LC50 values of 21.8 µg/adult and 287.0 µg/cm², respectively. The results indicated that the essential oil of S. riederi var. japonica and its isolates show potential as fumigants, and for their contact toxicity against grain storage insects.