Fumigant toxicity of Carum copticum and Vitex pseudo-negundo essential oils against eggs, larvae and adults of Callosobruchus maculatus

Fumigant activity of essential oil vapors distilled from Carum copticum C. B. Clarke and Vitex pseudo-negundo Hand I. MZT. 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 vapors 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 were found to be 1.01, 2.50 and 0.90 μl/l air of C. copticum oil, followed by 2.20, 8.42 and 9.39 μl/l air essential oil of V. pseudo-negundo, respectively. Between these essential oils, C. copticum was almost more toxic than V. pseudo-negundo 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.     

Cleome hirta essential oil as livestock tick (Rhipicephalus appendiculatus) and maize weevil (Sitophilus zeamais) repellent

The repellency of the essential oil of the shrub Cleome hirta and of three identified constituents (phytol, (+)-cedrol, n-octacosane) was evaluated against the livestock tick, Rhipicephalus appendiculatus and the maize weevil, Sitophillus zeamais. In a tick climbing repellency bioassay, the oil exhibited repellency which, at the highest dose, was comparable to that of the commercial arthropod repellent N,N-diethyltoluamide (DEET). In a Y-tube olfactometer bioassay, the oil showed higher or comparable repellency against S. zeamais relative to DEET at all the doses tested. The potential of C. hirta in livestock tick and maize weevil control is discussed.     

Chemical composition and bioactivities of three Chrysanthemum essential oils against Tribolium confusum (du Val) (Coleoptera: Tenebrionidae)

Essential oils from three species of Chrysanthemum growing in Tunisia (C. coronarium, C. fuscatum, and C. grandiflorum) were first analyzed by gas chromatography (GC) and GC/mass spectrometry (MS) and then evaluated for toxicity and antifeeding action against Tribolium confusum. The essential oils obtained from leaves and flowers shared a similar qualitative composition, but the relative proportions of the constituents were quite different. The essential oil of C. grandiflorum was rich in sesquiterpenoids, while those of C. fuscatum and C. coronarium were rich in monoterpenoids. The main common constituents of all the essential oils were ??-pinene, myrcene, ??-humulene, ??-caryophylene, spathulenol, and caryophyllene oxide. The most effective essential oil was obtained from the leaves of C. grandiflorum, that inhibited the relative growth rate (?0.03?mg/mg/d), efficiency of conversion of ingested food (?50.69%), relative consumption rate, caused an antifeeding effect (66.43%) and a high mortality (80%) of T. confusum larvae. Topical application C. grandiflorum essential oil caused a significant insect mortality that attends 27% after 7?days of treatment. While essential oil from C. coronarium flowers has contact and fumigant toxicity with a mortality of 9 and 13%, respectively. Results analysis highlights a relationship between essential oils composition and insecticidal activity against T. confusum. The study showed that each essential oil has specific chemical composition and act differently according to the nature of attributed test. The use of essential oils from different Chrysanthemum species with different methods helps poor farmers who store small amounts of grains to preserve it against pest infestation.     

Der MaiskäferSitophilus zeamais Motschulsky (Col., Curculionidae) und seine Begleitfauna — eine Freilandstudie auf den Philippinen

During the years 1982 to 1984 the attack ofSitophilus zeamais has been studied on corn fields owned by small-scale farmers in Cebu (Central Philippines). The invasion bySitophilus started 4 to 5 weeks before harvest and increased continously up to harvest time, when 93% of the drafted cobs could be occupied. A long lasting and for this region unusual drought (8 months) caused a drastic collapse of the population during the following planting season. But another planting season later the field population has been recovered and showed a high rate of infestation again. The frass-holes caused byHeliothis armigera, and said to be important as an “entry” forSitophilus, have been significant only during the beginning of the attack byS. zeamais, while the husk was still tight. During the corn ripening and the desiccation of the huskSitophilus has best chances to get into the cob without influence from outside. This stage coincides with the increase of the population density. The control ofH. armigera is not considered to be effective to keep the infestation ofSitophilus on a minimum level. A distinct orientation behaviour byS. zeamais regarding the main wind direction has been noticed in the field. BesideSitophilus the Nitidulid beetlesCarpophilus mutilatus and (but less important)C. humeralis have been found abundantly within the cobs. The drought did not show any obvious influence on the population ofC. mutilatus. Some further observations on the field infestation byS. zeamais are described.     

Endosymbiont load,personality and reproductive output of maize weevils (Sitophilus zeamais)

Journal of Pest Science - Endosymbiotic association is frequent in insects, and endosymbionts influence a range of biological processes in these organisms. The endosymbiont–insect association...     

Hyptis suaveolens and Hyptis spicigera (Lamiaceae) essential oils: qualitative analysis, contact toxicity and repellent activity against Sitophilus granarius (L.) (Coleoptera: Dryophthoridae)

Essential oils from Hyptis suaveolens (L.) Poiteau (Lamiaceae) and Hyptis spicigera Lamarck (Lamiaceae) were first analysed by gas chromatography and by gas chromatography/electron impact mass spectroscopy and then evaluated for toxicity and repellent activity against Sitophilus granarius (L.) (Coleoptera: Dryophthoridae), one of the most serious worldwide stored grain pests. Fifty-six compounds have been identified in the essential oil of H. suaveolens: monoterpene hydrocarbons were the most represented volatiles (64.1%), followed by sesquiterpene hydrocarbons (24.0%), oxygenated monoterpenes (8.1%) and oxygenated sesquiterpenes (2.4%). Diterpenes and non-terpene derivatives were scarcely represented. Sixty compounds have been identified in the essential oil of H. spicigera: monoterpene hydrocarbons were the most represented class of volatiles (70.4%), followed by sesquiterpene hydrocarbons (22.6%). Results from topical applications on insects showed that both essential oils had an effective insecticidal activity. The complete kill of S. granarius was observed 24 h after treatment at a minimum effective dose of 0.4 and 0.6 μl per insect with H. suaveolens and H. spicigera oil, respectively. Results from repellency tests showed that the two essential oils had a repellent activity on S. granarius adults: at the lowest dose (2 × 10⁻⁴ μl oil per cm²), H. spicigera essential oil exhibited a higher repellent effect in comparison to H. suaveolens. No significant differences were observed for the repellent effect between the two essential oils at the highest dose (2 × 10⁻² μl oil per cm²).     

Chemical composition,insecticidal and repellence activities of essential oils of three Achillea species against the Khapra beetle (Coleoptera: Dermestidae)

Essential oils of Achillea biebersteinii, Achillea santolina and Achillea mellifolium were obtained by hydrodistillation and analyzed using gas chromatography/mass spectrometry. The plant oils were tested for their toxic and repellent activities against the Khapra beetle, Trogoderma granarium (Everts) (Coleoptera: Dermestidae). T. granarium was sensitive to the oils via topical application, contact and fumigation bioassays, where A. biebersteinii oil was the most toxic regardless of the technique used. Using topical application, a dosage of 15 μg/mg insect of A. biebersteinii oil was sufficient to kill 100 and 83.2.0 % after 7 days exposure of adults and 2nd instar larvae, respectively. Meanwhile, twice this concentration of A. santolina and A. mellifolium oils caused 90.4 (72.5 %) and 73.8 (60.1 %) adult and larval mortality after 7 days, respectively. Using fumigation and 7 days exposure, a concentration of 50.0 μl/l air of A. biebersteinii oil displayed the strongest activity (percentage adult and larval mortalities of 100.0 and 88.0 %), respectively, while A. santolina and A. mellifolium oils at the same concentration caused 92.5 (76.8 %) and 76.1 (61.3 %) adult and larval mortality, respectively. The three oils were strongly repellent to the larvae and adults of T. granarium. The repellent activity was time and concentration-dependent, where A. biebersteinii oil was the most effective, even though at low concentrations (percentage repellency of 100 and 81.0 % were recorded against adults and larvae after 6 h exposure to a concentration of 0.22 μl/cm², respectively). Results suggested the potential use of Achillea oils as natural grain protectants against T. granarium.     

杉木心材精油对黑胸散白蚁的触杀毒性研究

以水蒸汽蒸馏法提取杉木心材精油,其精油得率为0.73％～0.79％.用毒土法进行杉木心材精油对黑胸散白蚁的触杀毒性试验,结果表明:杉木心材精油对黑胸散白蚁具有较强的触杀毒性,且其毒性的大小与处理时间和浓度有关;当其浓度为160m/L时,72 h内白蚁死亡率为100％.     

Kaolin spraying protects cotton plants against damages by boll weevil Anthonomus grandis Boheman (Coleoptera: Curculionidae)

The high cost of insecticides, the emergence of insecticide resistance in populations of a number of insect species and other problems arising from their continuous use, such as biological imbalance, cotton fiber waste, and environmental pollution, have prompted the development of new technologies aiming the control of Anthonomus grandis Boheman in cotton crops. This study evaluated the level of protection conferred by kaolin clay foliar spraying to cotton plants against boll weevil damage. Treatment-tested spraying kaolin or endosulfan on cotton plants. The highest percentage of oviposition-punctured squares were observed in the control, and the lowest percentages in the treatments sprayed with endosulfan and kaolin in a systematic manner and where the boll weevil reached the economic threshold at all assessments. The greatest numbers of non-attacked bolls by weevils and cotton-seed yield were observed under the endosulfan treatments, followed by the treatments of kaolin spraying. The smallest number of bolls and lowest cotton-seed yield were observed for the control plots. These finding are of practical significance because they may reduce the cotton production cost and environmental impacts of chemical pesticides and make possible the production of organic cotton with the presence of boll weevils.     

Impact of geochemical composition of diatomaceous earth on its insecticidal activity against adults of <Emphasis Type="Italic">Sitophilus oryzae</Emphasis> (L.) (Coleoptera: Curculionidae)

Laboratory experiments were done to determine the effect of geochemical composition of diatomaceous earth (DE) on insecticidal activity of DE against adults of the rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae). Samples of DE were mined from DE-deposits in Slovenia, Greece, and Serbia. In addition, a commercially available DE formulation (SilicoSec^®) was used in the tests and served as a positive control. The bioassays were carried out at temperatures 20, 25, and 30°C, relative humidity levels of 55 and 75%, and at application rates of 100, 300, 500, and 900 ppm. Adult mortality was recorded after 7, 14, and 21 days of exposure. Prior to bioassays with S. oryzae, the geochemical composition of all DEs that were used in the tests was determined by whole rock ICP geochemical analyses. Silica (in the form of SiO₂ or opal-A) was the DE ingredient that was significantly correlated with efficacy in most of the bioassays. Some weak positive correlation was observed between S. oryzae mortality and MnO or CaO content. All significant correlations between mortality and Al₂O₃, Fe₂O_3, K₂O, TiO₂, Cr₂O₃, P₂O₅, and MgO content were negative, while correlation between Na₂O content and mortality was generally not significant.     

Contact and fumigant toxicity of some essential oil constituents against a grain insect pest Sitophilus oryzae and two fungi, Aspergillus westerdijkiae and Fusarium graminearum

Bioassays were performed to determine the antifungal and insecticidal activity of clove essential oil (EO), several botanical compounds (eugenol, carvacrol, allylisothiocyanate (AITC) and ethyl formate (EtF)) against mycotoxigenic fungi (Aspergillus westerdijkiae and Fusarium graminearum) and the rice weevil, Sitophilus oryzae. Antifungal activity was quantified by measuring conidia germination inhibition and mycelial growth inhibition zone to determine the minimum inhibitory concentration (MIC). Mortality of insects was determined through either contact toxicity assay (impregnated filter paper) or fumigation toxicity assay (airtight exposure chamber). A four-parameter logistic regression of fungi inhibitory growth rate to the dose of tested substances, either by the agar diffusion assay or the micro-atmosphere test, showed that AITC had antifungal and sporicide activity. The concentration at MIC for A. westerdijkiae and F. graminearum was 24.2 and 19.8???l?l^?1, respectively, whereas clove essential oil (EO) was 755 and 352???l?l^?1 after 72?h incubation period. Bioassays with S. oryzae showed that clove EO contact insecticidal activity was similar to pure eugenol and carvacrol: LD₉₀s were 366, 385 and 442???l?dm^?2, respectively. The fumigation insecticidal activity of AITC was LC₉₅?=?10.8???l?l^?1. For EtF and clove EO, only the LC₅₀ could be accurately determined after 24?h exposure time which was observed at 41 and 210???l?l^?1, respectively (vs. 6.4???l?l^?1 for AITC LC₅₀). The combined antifungal activity on mycotoxigenic seed-borne fungi and insecticidal activity against the rice weevil demonstrated that AITC in vapour phase may be a promising active substance for the preservation grain stored in unsafe conditions with a risk of fungal growth.     

Abundance and pest classification of scolytid species (Coleoptera: Curculionidae, Scolytinae) follow different patterns

Scolytids have been studied more than any other group of forest insects, but most investigations have been restricted to only a few pest species. This bias hampers our understanding of variation in abundance and pest status. Even the simple question whether the abundance of scolytids can predicted by the same independent variables as their pest status is still a matter of debate. To explore this issue, we estimated their abundance using non-attracting flight-interception traps set in a wide range of forests across Czech Republic, Germany, and France. Pest status was taken from current literature. As independent variables, we considered host range, host abundance, and several traits of the considered species in linear models using generalized least squares with a correlation structure derived from the phylogenetic tree of the beetles. Host range was calculated as the root phylogenetic diversity index. The variation in the abundance across scolytids was well explained by resource-related parameters (R² = 0.53). In contrast to abundance, the pest status was significantly related to species-specific traits, such as body size and maximum number of generations. However, the explained variance was much lower (R² = 0.19). Although our analysis showed that abundance and pest score follow different patterns, we stress the importance of monitoring all species using non-selective traps. Considering the increasing global trade and the rapidly changing climate, such a broad ecological monitoring is necessary to detect new interactions and/or invading species that may influence our forests ecosystems.     

粗刻点木蠹象与云南木蠹象雌雄成虫区分方法

粗刻点木蠹象和云南木蠹象的雌雄成虫在外部形态上相似度很高,难以区分.文章介绍了2种区分方法.一是在解剖镜下通过观察象虫腹部背板末节上的特征准确区分活体雌雄成虫;二是通过肉眼观察象虫腹部第1节中间部位的特征快速区分活体雌雄成虫,可作为1种简便的野外区分方法.     

Efficacy of Clausena anisata and Plectranthus glandulosus leaf powder against Prostephanus truncatus (Coleoptera: Bostrichidae) and two strains of Sitophilus zeamais (Coleoptera: Curculionidae) on maize

Powdered leaves of Clausena anisata and Plectranthus glandulosus were evaluated on Cameroonian and German strains of Sitophilus zeamais and Prostephanus truncatus for their insecticidal activities, the effects on progeny production, grain damage and population increase by admixing powders and maize grains. The two powders caused significant mortality of the three insects with P. glandulosus being far more effective than C. anisata. P. truncatus was less susceptible to P. glandulosus powder compared with the two strains of S. zeamais. The German strain (LD₅₀ = 2.75 g/100 g grain) of S. zeamais was less susceptible to P. glandulosus powder than the Cameroonian strain (LD₅₀ = 1.86 g/100 g grain). P. glandulosus unlike C. anisata powder, considerably reduced grain damage, progeny production and population increase. This study shows that there is a great potential for the powder of P. glandulosus as a promising grain protectant for integration within the subsistence farming systems of sub-saharan Africa.     

木蠹象属(鞘翅目:象虫科)的种类、分布、寄主植物及潜在入侵威胁

木蠹象属是以松树木蠹象为模式种建立的属,是鞘翅目、象虫科、木蠹象亚科的唯一属.该属目前已记录种类46种,29种分布于美洲,18种分布在欧洲和亚洲,其中耐猛木蠹象是美洲、欧洲和亚洲共有的种类,它分布于美洲的美国、加拿大,欧洲的俄罗斯和亚洲的日本.木蠹象属许多种类是针叶树的重要害虫,且极易通过人为携带传播扩散.有3种分布区跨越欧洲和亚洲,葛氏木蠹象分布于俄罗斯的欧洲部分、德国和瑞典,亚洲的中国、日本和俄罗斯的亚洲部分(西伯利亚);圆角木蠹象分布于俄罗斯的欧洲部分和中国;樟子松木蠹象分布于法国和中国.木蠹象属的寄主植物均为针叶树,包括5属39种,以松属为寄主植物的有26种木蠹象,以云杉属、冷杉属、落叶松属和黄杉属为寄主植物的木蠹象分别为9、5、4和1种.分布于中国的木蠹象有7种,其中粗刻点木蠹象和云南松木蠹象是特有种类,葛氏木蠹象、圆角木蠹象和樟子松木蠹象是与欧洲共有的种类,黑木蠹象、葛氏木蠹象和红木蠹象与日本共有,红木蠹象与韩国共有.分布于日本的耐猛木蠹象和瘤木蠹象、俄罗斯西伯利亚的凸眼木蠹象以及日本、俄罗斯和韩国均有发生的黄星木蠹象,以及在中国均没有分布的美洲的29种木蠹象,都属于应加强检疫的对象,防止人为携带传入我国.     

Isolation and identification of entomopathogenic fungi and their evaluation against Tribolium confusum, Sitophilus zeamais, and Rhyzopertha dominica in stored maize

The objective of this study was to isolate and identify native entomopathogenic fungi from different components of maize agroecosystem, and evaluate their virulence against Tribolium confusum, Rhyzopertha dominica, and Sitophilus zeamais, three insect pest vectors of aflatoxigenic fungi. Paecilomyces and Metarhizium were the most abundant genera isolated from the soil. Identification of fungal cultures by DNA extraction, amplification, and sequencing showed that all isolates macro- and micromorphological identified as P. lilacinus were Purpureocillium lilacinum. The isolate JQ926223 showed the lowest LT₅₀ for T. confusum (4, 66 days) and R. dominica (9, 38 days), and the isolate JQ926212 demonstrated similar LT₅₀ for the three insects evaluated between the range of 11, 7 to 14, 95 days. Maximum mortality rate was observed for the isolate JQ926223. The isolates of Purpureocillium lilacinum JQ926223 and JQ926212 may be considered good candidates for biologic control in the ecosystem of stored maize.     

Effect of pre-germination treatment with direct magnetic field exposure: a systematic review and meta-analysis

The search for ecological technologies that favour germination processes in agricultural and forestry seeds is a topic of interest as an environmentally friendly option. This study was a systematic review and meta-analysis to examine whether magnetic field direct exposure of seeds has a specific effect on germination. Using Scopus (2000–2020) and Web of Science (2000–2020) databases, a bibliographic search was carried out using the following expressions (pre-sowing AND seed AND magnetic) to filter the references in the title, abstract and keywords of the articles published. The calculation and declaration of the effect size was performed by comparing binary results through applying the Odds-Ratio register with a 95% confidence interval (CI). The random effects model was applied with the DerSimonian and Laird method. A total of 175 articles were found, of which only 26 were accepted for systematic review and meta-analysis. Three subgroups were established according to the magnetic field strengths. The subgroup corresponding to intensities between 1 and 50 mT presented an Odds-Ratio of 0.49 with a CI of (0.19, 0.79), Q (14)?=?24.77, p?=?0.04, indicating that the treatment had a significant effect. The remaining subgroups showed no significant effect. Likewise, the global meta-analysis revealed a significant effect in favour of the treatment, with an Odds-Ratio of 0.68, a CI of (0.41, 0.94), Q (28)?=?44.03, p?=?0.03. From the studies included in the meta-analysis, the results show a significant effect of seed direct exposure to magnetic fields that can be used to increase seed germination.

     

Damage reduction and performance of mass trapping devices for forest protection against the spruce bark beetle, Ips typographus (Coleoptera Curculionidae Scolytinae)

? The spruce bark beetle, Ips typographus, is one of the main European forest pests, and mass trapping is probably the most common strategy applied to reduce its population density. However, the results concerning the effectiveness of this control system are often controversal, and many studies consider only the trapping performance with no attention to the damage reduction.

? During spring-summer 2005, a control program against I. typographus outbreaks was set up in NE Italy. Twenty-four spruce forests heavily infested by I. typographus were studied: six protected by pheromone slot-traps, six by horizontal trap-logs and six by standing trap-logs; six untreated stands were kept as controls. Trap-logs were baited with a pheromone specific to I. typographus and treated with insecticide. Each type of device was tested at high, medium and low density in relation to the number of trees infested during the previous year. New damage occurring in the investigated stands was later monitored for one year.

? Protected forests showed mean damage about 80% lower in 2005 than in 2004, with no statistical difference among traps, trap-logs or standing trap-logs. Instead, unprotected forests (controls) suffered damage to a similar extent in both years. Trapping devices showed no statistical differences among mean captures. Device densities showed similar results in damage reduction and insect trapping.

? The results support the hypothesis that intensive trapping performed at stand level may be useful for protecting forests against I. typographus, locally reducing population density and tree mortality.

     

Comparison of lure-baited insecticide-treated tripod trap logs and lure-baited traps for control of Ips duplicatus (Coleoptera: Curculionidae)

Two methods were compared for capturing the bark beetle Ips duplicatus Sahlberg (Coleoptera: Curculionidae, Scolytinae): lure-baited, insecticide-treated tripod trap logs (TRIPODs) versus Theysohn pheromone traps (TPTs). In 2008 and 2011 and at each of three clearcuts, five TPTs and five TRIPODs baited with ID Ecolure pheromone evaporators were installed with 10 m spacing. The pheromone evaporators were renewed every 8 weeks. The TRIPODs were treated with the insecticide Vaztak 10 EC in mid-April and then every 5 weeks thereafter. Trap logs and traps were inspected weekly during the entire period of I. duplicatus flight activity (April–September). Two to three times more beetles were trapped by the TPTs than by the TRIPODs. The TPTs captured more females than males, while TRIPODs captured equivalent numbers of males and females or more males than females on some dates. The TPTs and TRIPODs trapped approximately the same numbers of males, but the TPTs captured more females than the TRIPODs. Both traps captured more adults in spring than in summer. The higher numbers of entomophagous arthropods, including the predacious beetles Thanasimus formicarius L. and T. femoralis, were captured in the TRIPODs than in the TPTs.     

椰子大害虫-锈色棕榈象及其近缘种的鉴别(鞘翅目:象虫科)

锈色棕榈象Rhynchophorus ferrugineus(Oliver)隶属于鞘翅目Coleoptera 象虫科Curculionidae,近年在海南省严重危害椰子，文章介绍了该虫与同属近缘种美洲棕榈象Rhynchophorus palmarum（L.）等成虫，幼虫和蛹在形态特征上的区别。