Detection of wood boring insects by measurement of oxygen consumption

A possible method for detection of wood-boring insects in wood is the measurement of oxygen consumption. In order to develop such a method, several parameters have to be determined first. The most important one is to determine the respiration rate of possible pest species. To obtain the data for establishing the method mentioned above, the respiration rates of the following species were determined: the old house borer, Hylotrupes bajulus, common furniture beetle, Anobium punctatum and subterranean termite, Reticulitermes lucifugus. We compared the O₂ consumption between different species as well as between adults and larvae of one species in different environmental conditions (temperature, day/night and light/dark regime). The most intensive respiration rates were found for the larvae of Hylotrupes bajulus (4.0 ml/g h O₂) and Anobium punctatum (3.9 ml/g h O₂). Less intensive breathing was measured by Reticulitermes lucifugus (workers 2.9 ml/g h, nymphs 2.6 ml/g.h and soldiers 2.0 ml/g h O₂). These results indicate that it is possible to detect the presence of wood-boring insects respirometrically. To detect the presence of an individual insect in the wood by means of respirometry, the sensitivity of the instrument for oxygen measurement at the optimal conditions must be around 0.2 ml/h.     

Plant stress and insect behavior: cottonwood,ozone and the feeding and oviposition preference of a beetle

Summary Adults and larvae of the beetle Plagiodera versicolora preferred to feed on and consumed more of cottonwood, Populus deltoides, plant material that had been previously exposed to an acute dose of ozone (0.20 ppm, 5 h), compared to controls in choice experiments. However, females preferred to oviposit on the unexposed controls. Results were consistent for 2 cottonwood clones over 3 years in disc, leaf and whole-plant choice tests. The differential feeding and oviposition response of this insect to stressed plants could have at least 3 unexpected consequences: 1. An immediate increase in damage to stressed trees, but a subsequent decrease in damage. 2. A subsequent increase in damage to unstressed adjacent trees. 3. Changes in the insect and pathogen communities of both stressed and unstressed trees. These complex scenarios show that predicting outcomes of plant stress on plant-insect interactions will require comprchensive examination of behavioral, growth and reproductive responses of insects to stressed plants.     

Effects of leaf and sap feeding insects on photosynthetic rates of goldenrod

Summary Herbivory can alter the balance between sources and sinks within a plant, and changes in the source-sink ratio often lead to changes in plant photosynthetic rates. We investigated how feeding by three insect herbivores affected photosynthetic rates and growth of goldenrod (Solidago altissima). One, a phloem-sap feeding aphid (Uroleucon caligatum), creates an additional sink, and the other two, a leaf-chewing beetle (Trirhabda sp.) and a xylem-sap feeding spittlebug (Philaenus spumarius) both reduce source supply by decreasing leaf area. Plants were grown outside in large pots and insects were placed on them at predetermined densities, with undamaged plants included as controls. All insects were removed after a 12-day feeding period. We measured photosynthetic rates both of damaged leaves and of undamaged leaves that were produced after insect removal. Photosynthetic rates per unit area of damaged leaves were reduced by spittlebug feeding, but not by beetle or aphid feeding. Conductance of spittlebugdamaged leaves did not differ from controls, but internal carbon dioxide concentrations were increased. These results indicate that spittlebug feeding does not cause stomatal closure, but impairs fixation within the leaf. Effects of spittlebug feeding on photosynthetic rates persisted after the insects were removed from the plants. Photosynthetic rates per unit area of leaves produced after insect removal on spittlegug-damaged plants were lower than control levels, even though the measurements were taken 12 days after insect removal. The measurement leaf on spittlebugdamaged plants was reduced in area by 27% relative to the controls, but specific leaf area (leaf area/leaf weight) was increased by 18%. Because of the shift in specific leaf area, photosynthetic rates were also examined per unit leaf weight, and when this was done there were no significant differences between control and spittlebug-damaged plants. Beetle and aphid feeding had no effects on the photosynthetic rate of the leaves produced after insect removal. Plant relative growth rates (in terms of height) were reduced by spittlebugs during the period that the insects were feeding on the plants. Relative growth rates of spittlebug-damaged plants were increased above control levels after insect removal, but these plants were still shorter than controls 17 days after insect removal. Beetles and aphids did not affect plant relative growth rates or plant height. Feeding by both spittlebugs and beetles reduced leaf area, and the effect of the spittlebug was more severe than that of the beetle. These results show that effects of herbivory on photosynthetic rates cannot be predicted simply by considering changes in the source-sink ratio, and that spittlebug feeding is more damaging to the host plant than beetle or aphid feeding.     

A two-phase open-field test to evaluate the host-specificity of candidate biological control agents for Heliotropium amplexicaule

This paper describes an open-field host-specificity test conducted to make a preliminary evaluation of the safety of four candidate agents for the biological control of Heliotropium amplexicaule, an invasive weed of South American origin. These agents were a leaf-eating beetle, Deuterocampta quadrijuga, a flea-beetle, Longitarsus sp., that feeds on leaves as an adult and roots as a larva, a shoot-feeding thrips, Haplothrips heliotropica, and a cell-sucking bug, Dictyla sp. During the first phase of the experiment, the four agents were given a choice between the target weed and six species of nontarget plant of varying degrees of phylogenetic relatedness. All four species were found to feed and reproduce on only H. amplexicaule and the closely related H. nicotianaefolium (a member of the same section of the genus Heliotropium). No plants outside this genus were attacked. For the second “no-choice” phase, the host-plants used in Phase 1 were cut, forcing the insects to use either other plant species within the plots, emigrate, or die of starvation. Heliothrips heliotropica disappeared rapidly from the plot, while D. quadrijuga persisted for several days on Heliotropium arborescens with some exploratory nibbling and then disappeared. Host-choice behavior of these species therefore remained unchanged, even in the absence of the primary host-plants. In contrast, adults of Longitarsus sp. rapidly colonized and fed on H. arborescens when the preferred hosts were removed. It therefore demonstrated a wider host-range under these more extreme conditions. In fact, on some plots, feeding commenced on H. arborescens before the “no-choice” phase, once the two preferred Heliotropium species were heavily damaged by these insects. The two-phase test is shown here to be a useful way of measuring host-choice behavior under “normal” conditions of choice and under more extreme conditions, such as it might occur were an agent to locally destroy the target weed following its release. It therefore provides a more refined assessment of the risk that would be posed to nontarget plants by the release of weed biological control agents.     

Performance of leaf beetle larvae on sympatric host and non-host plants

Studies asking the ability of insects to utilize novel host plants often use novel hosts that are allopatric with the insect population under investigation. However, since the outcomes of species interactions are often site-specific, such studies cannot tell us whether a plant would actually be used by a given insect population if the plant grew sympatrically with it. We therefore performed a quantitative genetics experiment to analyse the performance of larvae of the leaf beetle Oreina elongata Suffrian (Coleoptera: Chrysomelidae, Chrysomelinae) on two host and three non-host plants, collected from a site where insects and plants co-occur in the Western Alps. When raised on the non-host Petasites albus (L.), larvae were able to survive equally well as on the two hosts, Adenostyles alliariae (Gouan) and Cirsium spinosissimum (L.), whereas they did not survive on the two other non-hosts, Peucedanum ostruthium (L.) and Rumex alpinus L. On P. albus, growth rate was slightly lower and development time slightly longer than on the two hosts. We found a genotype by environment interaction only for growth rate but not for development time and survival. However, the shape of the reaction norms of growth rates suggests that it is unlikely that selection could favour the inclusion of P. albus into the host range of the study population.     

Tracking down the "head blob": comparative analysis of wingless expression in the developing insect procephalon reveals progressive reduction of embryonic visual system patterning in higher insects

The evolution of larval head morphology in holometabolous insects is characterized by reduction of antennal appendages and the visual system components. Little insight has been gained into molecular developmental changes underlying this morphological diversification. Here we compare the expression of the segment polarity gene wingless (wg) in the pregnathal head of fruit fly, flour beetle and grasshopper embryos. We provide evidence that wg activity contributes to segment border formation, and, subsequently, the separation of the visual system and protocerebrum anlagen in the anterior procephalon. In directly developing insects like grasshopper, seven expression domains are formed during this process. The activation of four of these, which correspond to polar expression pairs in the optic lobe anlagen and the protocerebral ectoderm, has shifted to postembryonic stages in flour beetle and Drosophila. The remaining three domains map to the protocerebral neuroectoderm, and form by disintegration of a large precursor domain in flour beetle and grasshopper. In Drosophila, the precursor domain remains intact, constituting the previously described “head blob”. These data document major changes in the expression of an early patterning gene correlated with the dramatic evolution of embryonic visual system development in the Holometabola.     

Avidin and streptavidin as insecticidal and growth inhibiting dietary proteins

Avidin was found to be an insecticidal and growth inhibiting dietary protein for five species of Coleoptera (red flour beetle,Tribolium castaneum, confused flour beetle,T. confusum, sawtoothed grain beetle,Oryzaphilus surinamensis, rice weevil,Sitophilus oryzae, and lesser grain borer,Rhyzopertha dominica) and two species of Lepidoptera (European corn borer,Ostrinia nubilalis, and Indianmeal moth,Plodia interpunctella). At levels ranging from 10 to 1000 ppm in the diet depending on the species, avidin retarded the growth and caused mortality of all seven species. Addition of biotin to the avidin-treated diets forT. castaneum, T. confusum, R. dominica, andO. nubilalis prevented the growth inhibition and mortality caused by avidin. Streptavidin exhibited similar insecticidal and growth inhibiting activity towardsT. castaneum andO. nubilalis. The results support the hypothesis that feeding avidin or streptavidin to insects causes a biotin deficiency which in turn leads to stunted growth and mortality. Avidin and streptavidin are insect growth inhibiting proteins whose genes potentially could be manipulated into plants and provide host plant resistance to insect pests. This research was conducted by the Agricultural Research Service, U.S. Department of Agriculture in coperation with the Department of Biotechnology Research, Pioneer Hi-Bred International. Mention of an insecticide or proprietary product does not constitute a recommendation or endorsement by the USDA.     

First beetle elytra,abdomen (Coleoptera) and a mine trace from Lunz (Carnian,Late Triassic,Lunz‐am‐See,Austria) and their taphonomical and evolutionary aspects

Abstract: Four new species of Permosynidae are described: Platycrossus caroli Ponomarenko in Meller et al. sp. nov., Hydrobiites handlirschi Ponomarenko in Meller et al. sp. nov., Ademosyne polyzetete Ponomarenko in Meller et al. sp. nov. and Diarcuipenna bennettitophila Ponomarenko in Meller et al. sp. nov. Together with one polyphagous abdomen, they represent the first beetle remains from the Lunz formation, known for its richness in bennettite and cycad leaf remains and also for the bennettite reproductive organs. Furthermore, the first insect mine trace on a Nilssonia leaf segment is described, which is one of the most ancient linear mine traces. The rareness of insect remains in the plant‐bearing layers of the Lunz formation is still an enigma from the taphonomical–chemical point of view. The palaeoentomological and palaeobotanical considerations tentatively indicate a relationship between the rare occurrence of coniferous plants and the evolution or radiation of phytophagous insects during this time.     

Survey and prioritisation of potential biological control agents for prickly acacia (Acacia nilotica subsp. indica) in southern India

Prickly acacia, Acacia nilotica subsp. indica (Benth.) Brenan (Mimosaceae), a multi-purpose tree native to the Indian subcontinent, is a weed of national significance, widespread throughout the grazing areas of western Queensland and has the potential to spread throughout northern Australia. Biological control of prickly acacia has been in progress since the early 1980s, but with limited success to date. Based on genetic and climate matching studies, native surveys for potential biological control agents were conducted in 64 sites in Tamil Nadu state and eight sites in Karnataka state from November 2008 to December 2011. Surveys yielded 33 species of phytophagous insects (16 species of leaf-feeders, eight species of stem feeders, four species with leaf-feeding adults and root-feeding larvae, two stem-borers and bark-feeders and three flower-feeders) and two rust fungi. The number of species recorded at survey sites increased with the number of times the sites were surveyed. Using a scoring system based on field host range, geographic range, seasonal incidence and damage levels, we prioritised a scale insect (Anomalococcus indicus Ramakrishna Ayyar), two leaf-webbing caterpillars (Phycita sp. A and Phycita sp. B), a leaf weevil (Dereodus denticollis Boheman), a leaf beetle (Pachnephorus sp.), a gall-inducing rust (Ravenelia acacia-arabica Mundk. & Thirumalachari) and a leaf rust (Ravenelia evansii Syd. & P.) for detailed host specificity tests. The two rusts were sent to CABI-UK for preliminary host-specificity testing. Three insects (A. indicus, D. denticollis and Phycita sp. A) were imported into a quarantine facility in Brisbane, Australia where host-specificity tests are in progress.     

Cry1Ab protein levels in phytophagous insects feeding on transgenic corn: implications for secondary exposure risk assessment

Enzyme-linked immunosorbent assays (ELISA) and bioassays were used to estimate levels of Cry1Ab protein in four species of phytophagous insects after feeding on transgenic Bt-corn plants expressing Cry1Ab protein or artificial diets containing Cry1Ab protein. The level of Cry1Ab in insects feeding on sources containing the Cry1Ab protein was uniformly low but varied with insect species as well as food source. For the corn leaf aphid, Rhopalosiphum maidis (Fitch), feeding on diet solutions containing Cry1Ab protein, the level of the protein in the aphid was 250–500 times less than the original levels in the diet, whereas no Cry1Ab was detected by ELISA in aphids feeding on transgenic Bt-Corn plants. For the lepidopteran insects, Ostrinia nubilalis (Hübner), Helicoverpa zea (Boddie), and Agrotis ipsilon (Hufnagel), levels of Cry1Ab in larvae varied significantly with feeding treatment. When feeding for 24 h on artificial diets containing 20 and 100 ppm of Cry1Ab, the level of Cry1Ab in the larvae was about 57 and 142 times lower, respectively, than the original protein level in the diet for O. nubilalis, 20 and 34 times lower for H. zea, and 10 to 14 times lower for A. ipsilon. Diet incorporation bioassays with a susceptible insect (first instar O. nubilalis) showed significant Cry1Ab bioactivity present within whole body tissues of R. maidis and O. nubilalis that had fed on diet containing a minimum of 20 ppm or higher concentrations (100 or 200 ppm) of Cry1Ab, but no significant bioactivity within the tissues of these insects after feeding on transgenic Bt-corn plants. The relevance of these findings to secondary exposure risk assessment for transgenic Bt crops is discussed.     

Differential effects of foliar endophytic fungi on insect herbivores attacking a herbaceous plant

Foliar endophytic fungi appear to be ubiquitous in nature, occurring in a very wide range of herbaceous plants. However, their ecological role within forbs is very poorly known and interactions with foliar-feeding insects virtually unexplored. In this study, leaves of Cirsium arvense were infected with different combinations of endophyte fungi that had been previously isolated from this plant species. Two months later, leaf material was fed to larvae of a generalist insect, Mamestra brassicae, and adults of a specialist feeder, Cassida rubiginosa. Endophytes had different effects on the two insects; one species, Chaetomium cochliodes, reduced growth of M. brassicae but increased feeding by C. rubiginosa. Another species, Cladosporium cladosporioides, increased beetle feeding also, but had no effect on M. brassicae. Interactions were also seen between fungal species and dual infection with C. cladosporioides and Trichoderma viride greatly reduced beetle feeding. It is concluded that endophytes have significant effects on foliar feeding insects that differ with degree of specialism of the herbivore. We suggest that these effects are due to chemical changes in the host, brought about by fungal infection. These fungi have received remarkably little attention in the study of insect–plant interactions and yet could be important determinants of insect growth and even population dynamics.     

Presence of weed fungus in a non‐social beetle–fungus cultivation mutualism

1. Farming by non‐human organisms has arisen independently in several animal lineages, allowing them to survive on food sources that are otherwise difficult to access. However, agricultural gardens are prone to invasion by parasites that overgrow cultivars in the absence of host animals. The presence of garden parasites and associated host adaptations are well studied in advanced fungal agriculture practised by social insects (ants, termites, and ambrosia beetles), but the impact of garden parasites in more primitive forms of agriculture is poorly known. The aim of the present study was to report the presence of weed fungi in fungal gardens of the non‐social lizard beetle Doubledaya bucculenta Lewis (Coleoptera: Erotylidae: Languriinae), which cultivates the yeast Wickerhamomyces anomalus (E.C. Hansen) Kurtzman, Robnett & Bas.‐Powers in the internodes of recently dead bamboo culms. 2. The filamentous fungi Arthrinium spp., Fusarium spp., and an unidentified species were isolated from the inner wall and insect‐made wall debris of bamboo internodes inhabited by the beetle. 3. When cultured together with the yeast in the absence of host larvae, Arthrinium sp.1 outcompeted the yeast, suggesting that this filamentous fungus can invade yeast gardens but is normally suppressed under natural conditions. 4. Rearing experiments showed that beetle larvae grew faster when grown on yeast cultures than when fed only Arthrinium sp.1. 5. These results suggest that Arthrinium sp.1 acts as a weed in the fungal gardens of D. bucculenta, inhibiting both growth of the beetle larvae and proliferation of the beneficial yeast.     

Uncovering the Cultivable Microbial Diversity of Costa Rican Beetles and Its Ability to Break Down Plant Cell Wall Components

Coleopterans are the most diverse insect order described to date. These organisms have acquired an array of survival mechanisms through their evolution, including highly efficient digestive systems. Therefore, the coleopteran intestinal microbiota constitutes an important source of novel plant cell wall-degrading enzymes with potential biotechnological applications. We isolated and described the cultivable fungi, actinomycetes and aerobic eubacteria associated with the gut of larvae and adults from six different beetle families colonizing decomposing logs in protected Costa Rican ecosystems. We obtained 611 isolates and performed phylogenetic analyses using the ITS region (fungi) and 16S rDNA (bacteria). The majority of fungal isolates belonged to the order Hypocreales (26% of 169 total), while the majority of actinomycetes belonged to the genus Streptomyces (86% of 241 total). Finally, we isolated 201 bacteria spanning 19 different families belonging into four phyla: Firmicutes, α, β and γ-proteobacteria. Subsequently, we focused on microbes isolated from Passalid beetles to test their ability to degrade plant cell wall polymers. Highest scores in these assays were achieved by a fungal isolate (Anthostomella sp.), two Streptomyces and one Bacillus bacterial isolates. Our study demonstrates that Costa Rican beetles harbor several types of cultivable microbes, some of which may be involved in symbiotic relationships that enable the insect to digest complex polymers such as lignocellulose.     

Postgenomics of Tribolium: Targeting the endocrine regulation of diuresis

Coleopteran insects comprise a highly successful taxon, representing more than 25% of eukaryotic species, many of which are economically important. One of these, the red flour beetle (Tribolium castaneum H.), is a major pest of stored grain and cereal products and is also an excellent genetic model for the Coleoptera. The Tribolium genome sequencing project was recently completed, the first for an agricultural insect pest species. This genome sequence and annotation, in combination with the tractability of Tribolium for genetic dissection and functional genomic analysis, makes it one of the most useful subjects for studies of insect development, genetics and physiology. Tribolium has a number of interesting physiological adaptations, including desiccation tolerance associated with specialized cryptonephridial organs for active rectal absorption of atmospheric water. The study of endocrine regulation of diuresis in this species has led to the identification of a number of osmoregulatory peptides, including the novel arginine‐vasopressin‐like peptide.     

Developmental O-glycan profile analysis shows pentasaccharide mucin-type O-glycans are linked with pupation of Tribolium castaneum

Eukaryotic cells can decorate their proteins with carbohydrate structures or glycans, significantly affecting the properties and activities of these proteins. Despite the importance of protein glycosylation in numerous biological processes, our knowledge of this modification in insects is far from complete. While N-glycosylation is the most studied, the study of O-glycans in insects is still very fragmentary and these studies are limited to a specific developmental stage or a specific tissue. In this article, matrix-assisted laser desorption/ionization (MALDI)-Fourier transform ion cyclotron resonance (FTICR) mass spectrometry (MS) technology was used to analyze the O-glycan profile for the different developmental stages of egg, larva, pupa, and adult of the red flour beetle Tribolium castaneum, an important insect model and pest worldwide. The results on the O-glycan profile showed that the mucin-type glycans dominate the O-glycome of the red flour beetle. Interestingly, some of the more complex mucin-type O-glycans, such as a tetra- (O-GalNAcGalGlcAGalNAc) and pentasaccharide O-glycan (O-GalNAc(GalGlcA)GalNAcGlcA), were highly abundant during the pupa stage, the intermediate stage between larval and adult stage in holometabolous insects, demonstrating that insect metamorphosis is accompanied with a change in the insect O-glycan profile. Together with the N-glycan profile, the current data are a foundation to better understand the role of protein glycosylation in the development of insects.     

Cryptic local adaptation of the herbivorous ladybird beetle Henosepilachna pustulosa in the ability to use the thistle Cirsium boreale

Local adaptation to different host plants is important in the diversification of phytophagous insects. Thus far, much evidence of the local adaptation of insects with respect to host use at the physiological level has been gathered from systems involving less mobile insects and/or divergent hosts such as plants belonging to different families or genera. On the other hand, the prevalence of such local adaptation of insects with moderate or high dispersal ability to the intraspecific variation of herbaceous hosts is largely unknown. In the present study, we examined the occurrence and degree of local adaptation of the herbivorous ladybird beetle Henosepilachna pustulosa (Kôno) (Coleoptera: Coccinellidae) to its primary host, the thistle Cirsium boreale Kitam. (Asteraceae), through reciprocal laboratory experiments using beetles and thistles from three locations with a range of approximately 200 km. Concerning the larval developmental ability, obvious patterns of local adaptation to the thistles from respective natal locations were detected, at least in some combinations of beetle populations. Similar tendencies were detected concerning adult feeding acceptance, although the statistical support was somewhat obscure. Overall, our results indicate that the degree of local adaptation of insect species with moderate dispersal ability to conspecific herbaceous hosts is occasionally as strong as that involving less mobile insects and/or heterospecific hosts, indicating the potential of such cryptic local adaptation to promote ecological/genetic differentiation of phytophagous insect populations.     

Atomic Force Microscopy Study of Nano-Physiological Response of Ladybird Beetles to Photostimuli

Background

Insects are of interest not only as the most numerous and diverse group of animals but also as highly efficient bio-machines varying greatly in size. They are the main human competitors for crop, can transmit various diseases, etc. However, little study of insects with modern nanotechnology tools has been done.

Methodology/Principal Findings

Here we applied an atomic force microscopy (AFM) method to study stimulation of ladybird beetles with light. This method allows for measuring of the internal physiological responses of insects by recording surface oscillations in different parts of the insect at sub-nanometer amplitude level and sub-millisecond time. Specifically, we studied the sensitivity of ladybird beetles to light of different wavelengths. We demonstrated previously unknown blindness of ladybird beetles to emerald color (∼500nm) light, while being able to see UV-blue and green light. Furthermore, we showed how one could study the speed of the beetle adaptation to repetitive flashing light and its relaxation back to the initial stage.

Conclusions

The results show the potential of the method in studying insects. We see this research as a part of what might be a new emerging area of “nanophysiology” of insects.     

Climatic factors on entomopathogenic hyphomycetes infection of Trialeurodes vaporariorum (Homoptera: Aleyrodidae) in Mediterranean glasshouse tomato

Collaborative research was conducted at the INRA Research Centers to assess the microbial control potential of Beauveria bassiana- and Lecanicillium lecanii-based formulations against whiteflies in protected crops under Mediterranean conditions. Four series of small-scale glasshouse trials were performed in 1999 and 2000 in southern France. Two applications at 4–5 day intervals of Naturalis-L and Mycotal were conducted on young larvae of the greenhouse whitefly, Trialeurodes vaporariorum, at rates recommended by the manufacturers. Because of the expectation that environmental conditions prevailing in Mediterranean greenhouse crops may lead to greater climatic constraints for mycoinsecticide efficacy than in more temperate areas, manipulation of the greenhouse climate has been used to aim at optimizing mycoinsecticide efficacy. The climatic management strategy was mainly based on closing the ridge vents 2 h more at night-time in so-called “humid” glasshouse compartment than in a “dry” one. Thus, the daily period at high humidity (>90% RH) was two or three times longer in the “humid” compartment than in the “dry” one. In spite of this differential, mycoinsecticide treatments reduced numbers of surviving whitefly larvae by >85% in the “humid” compartment as expected as favorable, as well as in the “dry” compartment, expected as unfavorable. The results indicated clearly that both B. bassiana- and L. lecanii-based mycoinsecticides have a strong potential for microbial control of whitefly larvae infesting tomato crops at moderate ambient humidity in Mediterranean glasshouses. Our investigations provided strong arguments for explaining these unexpected results. The RH conditions prevailing in the targeted insect habitat should be greatly disconnected from that of the ambient glasshouse air. We suggest that strategies of mycoinsecticide optimization against phyllophagous insects in protected crops have to take into account factors acting on the leaf transpiration activity.     

Responses of a native beetle to novel exotic plant species with varying invasion history

相似文献   

Comparative analysis of insect control by nitrogen, argon and carbon dioxide in museum, archive and herbarium collections

An investigation of insect control using non-toxic methods was carried out in museums, archives and herbaria in different climatic regions. The efficacy of using modified atmospheres including nitrogen, argon and carbon dioxide to eliminate insect families was evaluated. Analyses were performed on eight different species, and all their development stages, in the families Cerambicidae, Anobiidae, Dermestidae and Lyctidae in the Coleoptera. The modified atmospheres were used in several treatment systems, i.e. plastic bags of low permeability, a fumigation vacuum chamber and a fumigation bubble, and the most appropriate conditions for disinfestation of ancient objects were assessed. An argon atmosphere achieved the best results for insect elimination with a short exposure time. Different species of Coleoptera were found to be resistant to carbon dioxide. From this study, a model of insect control was used in situ for art and historical collections.