Effectiveness of a naturally derived insecticide, spinosad, against the pine processionary moth Thaumetopoea wilkinsoni Tams (Lepidoptera: Thaumetopoeidae) under laboratory conditions

The pine processionary moth Thaumetopoea wilkinsoni Tams is a serious pest on pine trees in southwestern Turkey. The efficacy of a naturally derived insecticide, spinosad, on fourth-fifth instar larvae of T. wilkinsoni was studied under laboratory conditions. The product exhibited strong larvicidal activity and at doses above 5 mg litre(-1) caused > 90% mortality in the fourth-fifth larval stages of the species after 72 h. At 72 h the LD50 and LD90 values were 3.26 and 5.69 mg litre(-1) respectively. The results showed that spinosad is highly effective on T. wilkinsoni larvae.     

Chemical composition and larvicidal activities in vitro and in vivo of essential oils of Thymus vulgaris (L) and Lavandula angustifolia (Mill) against pine processionary moth Thaumetopoea pityocampa Den. & Schiff. in Ain Defla (Algeria)

Journal of Plant Diseases and Protection - Biological tests with Thymus vulgaris against both third and fifth instar larvae of Thaumetopoea pityocampa showed positive correlation between the used...     

Thaumetopoea solitaria Freyer (Lepidoptera: Thaumetopoeidae) in Israel

Thaumetopoea solitaria Freyer, the main insect pest ofPistacia spp. in Israel, occurs throughout most of the area of distribution of the genusPistacia in the country, except for the Negev. The larvae feed mainly onP. palaestina Boiss. andP. atlantica Desf., to a lesser degree onP. vera L., and rarely onP. lentiscus L. andSchinus terebinthifolius Raddi. The main flight period is in the first 3 weeks of October; the average duration of the incubation, larval development and hypogaeous stages is 143, 52 and 170 days, respectively. A prolonged diapause of 1–2 years is common. Of five species of Tachinidae,Drino imberbis (Wiedemann) was most common, parasitizing up to 10.1% of the pupae. Over the last 24 years one single outbreak occurred, in 1977–1981. Phonological differences amongTh. solitaria in Macedonia, Iran and Israel are discussed.     

A comparative evaluation of Origanum onites essential oil and its four major components as larvicides against the pine processionary moth, Thaumetopoea wilkinsoni Tams

The pine processionary moth (PPM), Thaumetopoea wilkinsoni Tams. (Lepidoptera: Thaumatopoeidae), is an important forest pest in the Mediterranean area, and urticating hairs of the caterpillars of this species cause allergic reactions on skin of humans and animals. In the present study, the larvicidal activities of Turkish oregano (Origanum onites L.) essential oil and its four major components, carvacrol, gamma-terpinene, terpinen-4-ol and thymol, were evaluated against fourth/fifth-instar larvae of PPM under laboratory conditions. The essential oil was larvicidal to PPM with an LD(50) value of 3800 microL L(-1) when 0.1 mL was applied per larva. Carvacrol was the most toxic component found in the essential oil (LD(50) = 3100 microL L(-1)), followed by thymol (LD(50) = 5500 microL L(-1)). The other two components, gamma-terpinene and terpinen-4-ol, were less effective. The results showed that Turkish oregano essential oil and its two components, carvacrol and thymol, could be potential alternatives to synthetic insecticides for the control of PPM.     

Insecticidal activities of leaf and twig essential oils from Clausena excavata against Aedes aegypti and Aedes albopictus larvae

BACKGROUND: The current study investigates, for the first time, the mosquito larvicidal activities of leaf and twig essential oils from Clausena excavata Burm. f. and their individual constituents against Aedes aegypti L. and Aedes albopictus Skuse larvae. The yields of essential oils obtained from hydrodistillation were compared, and their constituents were determined by GC‐MS analyses. RESULTS: The LC₅₀ values of leaf and twig essential oils against fourth‐instar larvae of Ae. aegypti and Ae. albopictus were 37.1–40.1 µg mL^?1 and 41.1–41.2 µg mL^?1 respectively. This study demonstrated that C. excavata leaf and twig essential oils possess mosquito larvicidal activity, inhibiting the growth of mosquito larvae for both species at a low concentration. In addition, results of larvicidal assays showed that the effective constituents in leaf and twig essential oils were limonene, γ‐terpinene, terpinolene, β‐myrcene, 3‐carene and p‐cymene. The LC₅₀ values of these constituents against both mosquito larvae were below 50 µg mL^?1. Among these effective constituents, limonene had the best mosquito larvicidal activity, with LC₅₀ of 19.4 µg mL^?1 and 15.0 µg mL^?1 against Ae. aegypti and Ae. albopictus larvae respectively. CONCLUSION: The findings suggested that the essential oils from Clausena excavata leaf and twig and their effective constituents may be explored as a potential natural larvicide. Copyright © 2008 Society of Chemical Industry     

Insecticidal properties of essential plant oils against the mosquito Culex pipiens molestus (Diptera: Culicidae)

The insecticidal activities of essential oil extracts from leaves and flowers of aromatic plants against fourth-instar larvae of the mosquito Culex pipiens molestus Forskal were determined. Extracts of Myrtus communis L were found to be the most toxic, followed by those of Origanum syriacum L, Mentha microcorphylla Koch, Pistacia lentiscus L and Lavandula stoechas L with LC50 values of 16, 36, 39, 70 and 89 mg litre-1, respectively. Over 20 major components were identified in extracts from each plant species. Eight pure components (1,8-cineole, menthone, linalool, terpineol, carvacrol, thymol, (1S)-(-)-alpha-pinene and (1R)-(+)-alpha-pinene) were tested against the larvae. Thymol, carvacrol, (1R)-(+)-alpha-pinene and (1S)-(-)-alpha-pinene were the most toxic (LC50 = 36-49 mg litre-1), while menthone, 1,8-cineole, linalool and terpineol (LC50 = 156-194 mg litre-1) were less toxic.     

Insecticidal and behavioral effects of some plant essential oils against Sitophilus granarius L. and Tribolium castaneum (Herbst)

Journal of Plant Diseases and Protection - Insecticidal, repellent and fumigant activities of Rosemary [Rosmarinus officinalis (Lamiaceae)], Daphne [Laurus nobilis (Lauraceae)], Echinacea...     

四种非寄主植物精油对小菜蛾的生物活性

为寻找小菜蛾Plutella xylostella绿色防控方法,于室内测定辣蓼、迷迭香、芸香和紫苏4种非寄主植物精油对小菜蛾的生物活性。结果表明,辣蓼植物精油对小菜蛾2龄幼虫的毒杀作用最强,24、48和72 h时的致死中浓度LC50分别为2.18、1.78和1.46μg/μL,芸香植物精油次之;当芸香植物精油浓度为15μg/μL时,小菜蛾3龄幼虫的选择拒食率最高,作用24 h和48 h时分别为100.00%和92.84%,而在10μg/μL浓度下作用24 h和48 h时非选择拒食率达到最高值,分别为65.72%和42.72%;在4种植物精油中,芸香植物精油对小菜蛾3龄幼虫的生长抑制作用最明显,相对生长率最低,为-34.72%,生长抑制率最高,为133.74%,辣蓼植物精油的生长抑制效果次之,迷迭香和紫苏植物精油的抑制作用相对较差;小菜蛾雌、雄成虫对4种植物精油均表现出一定的触角电位反应和驱避活性,其中,芸香植物精油的驱避效果最明显;气相色谱-质谱分析结果显示,芸香植物精油的主要成分为β-石竹烯、（+）-α-蒎烯和β-蒎烯。表明芸香植物精油对小菜蛾具有显著的生物活性,具备开发为小菜蛾靶标...     

Insecticidal activity of 23 essential oils and their major compounds against adult Lipaphis pseudobrassicae (Davis) (Aphididae: Homoptera)

Essential oils from 23 species of plants comprising 14 genera and 4 plant families were obtained by Clevenger-type water distillation. The major compounds in these essential oils were identified with GC-MS and their insecticidal activity against adult turnip aphids, Lipaphis pseudobrassicae (Davis), tested with dosage-mortality bioassays. We examined mortality only for viviparous adults because sizeable aphid populations on crucifer (Brassicaceae) hosts are largely produced by these wingless, parthenogenic females. Twenty-two of the oils were directly applied to aphid females in randomized blocks at concentrations of 0.0, 1.0, 2.5, 5.0 and 10.0 mg ml(-1). Essential oils mixed with a non-toxic emulsifying agent, dimethyl sulfoxide (DMSO), more easily penetrated the waxy insect cuticle. Probit analysis and LC(50) at three different exposures showed aphids were quickly incapacitated and killed by aliphatic aldehydes, phenols and monocyclic terpenes contained in Bifora and Satureja oils and at applied concentrations as low as 0.3 to 1.0 mg ml(-1). Only enough Pimpinella isaurica oil and its three phenylpropanoid fractions were available for testing at a single concentration of 10 mg ml(-1). We could not spare any additional P. isaurica oil for testing at other concentrations. Phenylpropanoids isolated from P. isaurica oil when recombined or left naturally blended in the oil were highly bioactive against L. pseudobrassicae at 10 mg ml(-1).     

Insecticidal toxicity of thirteen commercial plant essential oils against <Emphasis Type="Italic">Spodoptera exigua</Emphasis> (Lepidoptera: Noctuidae)

We evaluated the chemical composition of thirteen commercially available plant essential oils and their insecticidal activity against the beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae). Gas chromatography-mass spectrometry was used to characterize the chemical components of the essential oils. A total of 113 compounds were identified, with terpenes (>80%) and aromatic compounds as primary constituents. The toxicity of each pure essential oil was tested separately on third instar larvae and adult beet armyworms by topical application of 0.5 μl oil/ insect. All plant essential oils were found to be harmful to S. exigua, with third instar larvae showing significantly more susceptibility than adults. Essential oils of Cinnamomum zeylanicum and Juniperus virginiana showed the highest toxicity (mortality above 90%) to larvae, while C. zeylanicum and Pogostemon cablin oils were the most harmful compounds (95% mortality) to adults. Cymbopogon winterianus oil caused delayed mortality (similar to the effects of insect growth regulators) as well as malformations in pupae. C. winterianus, Ocimum basilicum and Rosmarinus officinalis oils significantly reduced fecundity, whereas no significant effects were observed on fertility.     

4种植物挥发油的化学成分分析及其对赤拟谷盗的生物活性

本试验采用水蒸气蒸馏法提取飞机草?假蒟?紫穗槐和毛麝香4种植物的挥发油, 以气相色谱-质谱联用(GC-MS)分析挥发油的化学成分组成, 采用触杀和驱避活性测试评价以上植物挥发油对赤拟谷盗的生物活性?结果表明, 从上述植物挥发油中共鉴定出100种成分, 其中, 飞机草轻油和飞机草重油主要含有肉豆蔻醚(34.32%, 46.58%)和β-石竹烯(22.35%, 17.98%), 假蒟挥发油中主要含有β-胡椒烯(18.23%)和β-石竹烯(14.60%), 紫穗槐挥发油主要含有α-蒎烯(26.31%), 毛麝香挥发油主要含有γ-松油烯(24.90%)和环葑莰烯(16.59%)?此外, 飞机草轻油和重油?假蒟?紫穗槐和毛麝香挥发油对赤拟谷盗具有一定的触杀活性, 其24 h的LD50分别为58.83?62.73?51.94?44.08 μg/头和51.69 μg/头, 其中, 紫穗槐挥发油的触杀活性最强?同时, 上述植物挥发油对赤拟谷盗均具有一定的驱避活性, 其相对关联度ri分别为0.340 6?0.647 4?0.561 2?0.523 5和0.657 2, 其中, 毛麝香挥发油的驱避活性最强(ri =0.657 2)?因此, 紫穗槐和毛麝香挥发油在仓储害虫防治方面具有很好的研究价值和开发潜力?     

Insecticidal action of mammalian galectin‐1 against diamondback moth (Plutella xylostella)

BACKGROUND: Previous studies showed that mammalian galectin‐1 (GAL1) could interact with chitosan or chitin, one component of the peritrophic membrane (PM). This finding suggests that the PM could be a target of GAL1, which prompted the authors to explore the effect of GAL1 on larval growth and its potential mechanism. RESULTS: The development of Plutella xylostella (L.) larvae was significantly disturbed after they were fed recombinant GAL1. The histochemical structure and immunostaining pattern suggested that GAL1 treatment resulted in dose‐ and time‐dependent disruption of the microvilli and abnormalities in these epithelial cells. Ultrastructural studies showed that the PM was not present in the midgut of GAL1‐treated insects; instead, numerous bacteria were found in the lumen area. These results indicate that the protective function of the PM was disrupted by GAL1 treatment. Moreover, in vitro data showed that GAL1 interacts with chitosan/chitin in a dose‐dependent manner, and also specifically binds to the PM in vitro. CONCLUSION: In view of the fact that the carbohydrate recognition domain of GAL1 recognises the structural motif N‐acetyl lactosamine (Gal β 1–4 GlcNAc), which is similar to that of chitin (β‐1,4 N‐acetyl‐D ‐glucosamine), it is proposed that the insecticidal mechanism of GAL1 involves direct binding with chitin to interfere with the structure of the PM. Copyright © 2009 Society of Chemical Industry     

藜不同溶剂提取物的杀蚜活性

以萝卜蚜为试虫,对4种不同溶剂藜提取物的杀蚜活性进行了研究。结果表明,石油醚和乙醇提取物的杀虫活性最为显著,对萝卜蚜有很强的触杀和拒食作用,石油醚提取物72 h的平均拒食率为73.33%,拒食中浓度AFC_(50)为61.731 mg/mL,触杀校正死亡率为97.69%,LC_(50)为22.431 mg/mL;乙醇提取物72 h的触杀校正死亡率为93.82%,LC_(50)为34.698 mg/mL,与对照组具有显著差异。此外,藜其他溶剂提取物也表现出一定的杀蚜活性。     

Chemical composition and repellent activity of essential oils from the leaves of Cinnamomum zeylanicum and Eugenia uniflora against Diaphania hyalinata L. (Lepidoptera: Crambidae)

Journal of Plant Diseases and Protection - Diaphania hyalinata is an important pest in organic melon crops and has caused considerable harm to growers in northeastern Brazil. The aim of the present...     

Toxicity of azinphos-methyl to various development stages of the codling moth Cydia pomonella (Lepidoptera: Tortricidae)

The response to azinphos-methyl of different life-stages of the codling moth Cydia pomonella (L.) was studied. A similarity in response to azinphos-methyl (LC(50), LC(90)) was observed in neonate larvae obtained from the first and second generations of field populations. Mortality rates for neonate larvae of a field population cross-bred with a laboratory colony were lower (by a factor of 1.2-2.2) in comparison with field neonate larvae. The mortality rate of larvae from a laboratory colony exposed to artificial diet containing azinphos-methyl gradually decreased at older instars. The mortality rates of fifth-instar larvae were remarkably low when exposed to artificial diet mixed with azinphos-methyl or when topically treated with the insecticide. One- to three-day-old females were more sensitive than males of the same age, whereas the opposite was observed in 14-to 17-day-old adults. Mortality rates of 14- to 17-day-old adults were higher than those under 10 days old. No significant difference in sensitivity to the organophosphorus compound was noticed between the sexes of 7- to 10-day-old adults. Neonate larvae of the codling moth can serve as a target life-stage for various groups of pesticides, and the importance of using such a stage as a standardized methodology for monitoring resistance in the codling moth is discussed.     

Insecticidal activity of destruxin, a mycotoxin from Metarhizium anisopliae (Hypocreales), against Spodoptera litura (Lepidoptera: Noctuidae) larval stages

BACKGROUND: The cyclodepsipeptide destruxin produced by the entomopathogen Metarhizium anisopliae (Metch.) was administered by different methods, topical application, ingestion and a combination of the two, in an attempt to minimize the mycotoxin dose for efficient management of the insect pest Spodoptera litura (Fab.).RESULTS: The insecticidal activity of destruxin on the larval stages of S. litura showed an ascending trend in LD(50) values with increasing age. The value for 12-day-old larvae in the combined application assay was as low as 0.045 microg g(-1) body weight of crude destruxin from M-19 strain when compared with the corresponding values of 0.17 microg g(-1) body weight in the ingestion assay and 0.237 microg g(-1) body weight in the topical application assay. On the other hand, values were higher in the treatments with crude destruxin from the low-virulence M-10 strain of M. anisopliae showing the least quantities of A and E components of destruxin.CONCLUSION: Laboratory bioevaluation showed the combination assay of ingestion and topical application of crude destruxin to be efficient in enhancing its insecticidal properties. The adopted combination assay apparently simulates application of the insecticide at field level. Quantitative differences between destruxins from low- and high-virulence strains of M. anisopliae are in accordance with its presumed role in virulence.     

Composition and biological activity of essential oils from Labiatae against Nezara viridula (Hemiptera: Pentatomidae) soybean pest

BACKGROUND: Plant essential oils have been recognised as an important natural source of insecticide. This study analysed the chemical constituents and bioactivity of essential oils that were isolated via hydrodistillation from Origanum vulgare L. (oregano) and Thymus vulgaris L. (thyme) against eggs, second instar and adults of Nezara viridula (L.). RESULTS: The major component of oregano was p‐cymene, and, for thyme, thymol. The ovicidal activity was tested by topical application; the essential oil from thyme was more effective. The fumigant activity was evaluated in an enclosed chamber; the LC₅₀ values for oregano were 26.8 and 285.6 µg mL^?1 for nymphs and adults respectively; for thyme they were 8.9 µg mL^?1 for nymphs and 219.2 µg mL^?1 for adults. To evaluate contact activity, a glass vial bioassay was used; the LC₅₀ values for oregano were 1.7 and 169.2 µg cm^?2 for nymphs and adults respectively; for thyme they were 3.5 and 48.8 µg cm^?2 respectively. The LT₅₀ analyses for contact and fumigant bioassays indicated that thyme was more toxic for nymphs and adults than oregano. Both oils produced repellency on nymphs and adults. CONCLUSION: These results showed that the essential oils from O. vulgare and T. vulgaris could be applicable to the management of N. viridula. Copyright © 2011 Society of Chemical Industry     

Insecticidal and repellent properties of nine volatile constituents of essential oils against the American cockroach,Periplaneta americana (L.)

The toxic and repellent properties of nine major constituents of essential oils, comprising benzene derivatives and terpenes, were evaluated against Periplaneta americana (L.). Contact and fumigant toxicities to adult females and repellency to nymphs were determined. The decreasing order of knockdown activity via contact was methyl-eugenol>isosafrole=eugenol>safrole. The killing effect via contact was in the order eugenol=methyl-eugenol=isosafrole>safrole. Fumigant toxicity was only observed for safrole and isosafrole, with safrole being the more potent. Isoeugenol and the tested terpenes had neither contact nor fumigant toxic effect. The decreasing order of repellency to nymphs was safrole>isosafrole>methyl-eugenol=α-pinene> eugenol>isoeugenol. The benzene derivatives were generally more toxic and repellent to P. americana than the terpenes. The distance of the side chain double bond from the aromatic ring and the substitution of a methoxy group to these compounds appeared to be important determinants of their toxicity and repellency. © 1998 Society of Chemical Industry