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Based on available literature, ecology and economy of LED (light emitting diode) lights in plant foods production were assessed and compared to HPS (high pressure sodium) and CFL (compact fluorescent light) lamps. The assessment summarises that LEDs are superior compared to other lamp types. LEDs are ideal in luminous efficiency, life span and electricity usage. Mercury, carbon dioxide and heat emissions are also lowest in comparison to HPS and CFL lamps. This indicates that LEDs are indeed economic and eco-friendly lighting devices. The present review indicates also that LEDs have many practical benefits compared to other lamp types. In addition, they are applicable in many purposes in plant foods production. The main focus of the review is the targeted use of LEDs in order to enrich phytochemicals in plants. This is an expedient to massive improvement in production efficiency, since it diminishes the number of plants per phytochemical unit. Consequently, any other production costs (e.g., growing space, water, nutrient and transport) may be reduced markedly. Finally, twenty four research articles published in 2013–2017 were reviewed for targeted use of LEDs in the specific, i.e. blue range (400–500 nm) of spectrum. The articles indicate that blue light is efficient in enhancing the accumulation of health beneficial phytochemicals in various species. The finding is important from the global food production.

Chemical communication is ubiquitous. The identification of conserved structural elements in visual and acoustic communication is well established, but comparable information on chemical communication displays (CCDs) is lacking. We assessed the phenotypic integration of CCDs in a meta‐analysis to characterize patterns of covariation in CCDs and identified functional or biosynthetically constrained modules. Poorly integrated plant CCDs (i.e. low covariation between scent compounds) support the notion that plants often utilize one or few key compounds to repel antagonists or to attract pollinators and enemies of herbivores. Animal CCDs (mostly insect pheromones) were usually more integrated than those of plants (i.e. stronger covariation), suggesting that animals communicate via fixed proportions among compounds. Both plant and animal CCDs were composed of modules, which are groups of strongly covarying compounds. Biosynthetic similarity of compounds revealed biosynthetic constraints in the covariation patterns of plant CCDs. We provide a novel perspective on chemical communication and a basis for future investigations on structural properties of CCDs. This will facilitate identifying modules and biosynthetic constraints that may affect the outcome of selection and thus provide a predictive framework for evolutionary trajectories of CCDs in plants and animals., The project was supported by the Graduate School ‘Evolutionary Networks: Organisms, Reactions, Molecules’ (E‐Norm) of the Heinrich‐Heine‐University, Düsseldorf, Germany, the Max Planck Society and the Deutsche Forschungsgemeinschaft (DFG JU 2856/1‐1 and DFG JU 2856/2‐2).

Plants emit biogenic volatile organic compounds (BVOCs) causing transcriptomic, metabolomic and behavioral responses in receiver organisms. Volatiles involved in such responses are often called "plant language". Arthropods having sensitive chemoreceptors can recognize language released by plants. Insect herbivores, pollinators and natural enemies respond to composition of volatiles from plants with specialized receptors responding to different types of compounds. In contrast, the mechanism of how plants "hear" volatiles has remained obscured. In a plant-plant communication, several individually emitted compounds are known to prime defense response in receiver plants with a specific manner according to the chemical structure of each volatile compound. Further, composition and ratio of volatile compounds in the plant-released plume is important in plant-insect and plant-plant interactions mediated by plant volatiles. Studies on volatile-mediated plant-plant signaling indicate that the signaling distances are rather short, usually not longer than one meter. Volatile communication from plants to insects such as pollinators could be across distances of hundreds of meters. As many of the herbivore induced VOCs have rather short atmospheric life times, we suggest that in long-distant communications with plant volatiles, reaction products in the original emitted compounds may have additional information value of the distance to emission source together with the original plant-emitted compounds.

Plants emit a plethora of volatile organic compounds, which provide detailed information on the physiological condition of emitters. Volatiles induced by herbivore feeding are among the best studied plant responses to stress and may constitute an informative message to the surrounding community and further function in plant defence processes. However, under natural conditions, plants are potentially exposed to multiple concurrent stresses with complex effects on the volatile emissions. Atmospheric pollutants are an important facet of the abiotic environment and can impinge on a plant's volatile-mediated defences in multiple ways at multiple temporal scales. They can exert changes in volatile emissions through oxidative stress, as is the case with ozone pollution. The pollutants, in particular, ozone, nitrogen oxides and hydroxyl radicals, also react with volatiles in the atmosphere. These reactions result in volatile breakdown products, which may themselves be perceived by community members as informative signals. In this review, we demonstrate the complex interplay among stresses, emitted signals, and modification in signal strength and composition by the atmosphere, collectively determining the responses of the biotic community to elicited signals.

Summary 1. Many plant species have two inducible indirect defences against herbivores, emission of volatile organic compounds (VOCs) and secretion of extrafloral nectar (EFN). Moreover, herbivore-induced VOCs can serve as airborne signals in plant–plant communication, inducing and/or priming defences in undamaged neighbouring plants. However, it remains largely unknown, particularly in woody plants, whether herbivore-induced VOCs induce and/or prime these two indirect defences simultaneously. 2. We investigated the VOC-mediated induction and priming of VOC emission and EFN secretion in the woody plant hybrid aspen (Populus tremula × Populus tremuloides) in the context of plant–plant communication. Hybrid aspen saplings were exposed to VOCs released either from herbivore-infested or uninfested conspecifics and subsequently challenged by herbivores. VOCs and EFN from exposed plants were collected throughout experiments. Additionally, local and systemic EFN induction was investigated. 3. Exposure to VOCs from infested plants directly induced secretion of EFN sugars but not emission of volatile terpenes. Upon subsequent herbivore attack, however, plants previously exposed to herbivore-induced VOCs released significantly more terpenes than unexposed plants, whereas EFN secretion was not increased, indicating that herbivore-induced VOCs prime VOC emission but not EFN secretion. This switching in the indirect defence priority from induced EFN secretion to primed VOC emission may reflect the potential fitness disadvantages of VOC emission and EFN secretion on their own. In addition, feeding by Epirrita autumnata larvae reduced EFN sugar production both locally and systemically, which disagrees with previous findings and suggests that EFN secretion varies depending on plant and herbivore species. 4. Thereby, our work has parallels and divergences from the most significant previous studies. Nevertheless, it suggests that plants can respond differently to early warning signals and ensuing herbivory and in doing so fine-tune their different indirect defences timely to achieve optimal use of resources.

• It has been suggested that autumn-migrating insects drive the evolution of autumn leaf colours. However, evidence of genetic variation in autumn leaf colours in natural tree populations and the link between the genetic variation and herbivore abundances has been lacking. • Here, we measured the size of the whole aphid community and the development of green-yellow leaf colours in six replicate trees of 19 silver birch (Betula pendula) genotypes at the beginning, in the middle and at the end of autumn colouration. We also calculated the difference between green leaf and leaf litter nitrogen (N) and estimated the changes in phloem sap N loading. • Autumn leaf colouration had significant genetic variation. During the last survey, genotypes that expressed the strongest leaf reflectance 2-4 wk earlier had an abundance of egg-laying Euceraphis betulae females. Surprisingly, the aphid community size during the first surveys explained N loss by the litter of different birch genotypes. • Our results are the first evidence at the tree intrapopulation genotypic level that autumn-migrating pests have the potential to drive the evolution of autumn leaf colours. They also stress the importance of recognizing the role of late-season tree-insect interactions in the evolution of herbivory resistance.

Plant defence can be induced by exposing plants to the plant hormone jasmonic acid (JA) or its volatile ester, methyl jasmonate (MeJA). Carrageenans (Carr) - sulphated D-galactans extracted from red algae - can also induce plant defences. In this study, the effects of exogenous MeJA and Carr application (concentration 300 and 12.7 μmol, respectively) on volatile emissions from two widespread evergreen woody species, Pinus sylvestris (nine Turkish and one Finnish provenance) and Quercus ilex (Italian provenance) were investigated. We collected headspace samples from seedlings and analysed the quality and quantity of volatile compounds emitted by treated and control plants. In total, 19 monoterpenes, 10 sesquiterpenes, 10 green leaf volatiles (GLVs) and two aromatic compounds were emitted by P. sylvestris from all the provenances studied. Foliar MeJA application clearly affected the volatile profiles of trees from all the provenances. Effects of Carr were genotype specific. In Q. ilex, emissions of sesquiterpenes, GLVs and the homoterpene (E)-DMNT were all induced by MeJA application. However, emissions of most constitutively emitted monoterpenes were significantly reduced. Carr application also led to a significant reduction in monoterpene emissions, but without corresponding increases in other emissions. Our results indicate that exogenously applied MeJA and Carr can both significantly modify the volatile profiles of P. sylvestris and Q. ilex, but also that there are important provenance- and species-specific differences in the overall degree of elicitation and compositions of elicited compounds.

The use of plant-based compounds to control insect pests is an alternative to the use of synthetic pesticides. We evaluated the repellent and antifeedant effects of Cordeauxia edulis Hemsley (Fabaceae) and Rhododendron tomentosum Harmaja (Ericaceae) extracts against Hylobius abietis L. (Coleoptera: Curculionidae) and Phyllodecta laticollis Suffrian (Coleoptera: Chrysomelidae). Repellent properties were evaluated by monitoring responses of adult insects toward the odor from extracts or extraction solvents (controls) in a Y-tube olfactometer, and choice or no-choice feeding tests were conducted by applying extracts or extraction solvents on stems of Scots pine [Pinus sylvestris L. (Pinaceae)] and European aspen [Populus tremula L. (Salicaceae)], host plants of H. abietis and P. laticollis, respectively. Extracts of R. tomentosum repelled adults of both insect species effectively. However, extracts of C. edulis did not repel H. abietis although its ethyl acetate extract showed repellence against the adults of P. laticollis. Feeding by H. abietis was significantly reduced by a methanol extract of C. edulis, and methanol and hexane extracts of R. tomentosum. Feeding by the adults and larvae of P. laticollis was significantly reduced by extracts from both plant species. Concomitant with less feeding, larval growth was retarded by ethyl acetate extracts of both plant species. Gas chromatography-mass spectrometry analyses of the volatile components of the extracts showed that extracts from both plant species were mixtures of various terpene and non-terpene compounds, which showed quantitative and/or qualitative variations between plant species and extraction solvents. This experiment showed that extracts from both plant species effectively manipulated the orientation and/or feeding behavior of the two beetle species. Hence, they may be considered as potential alternatives to synthetic chemical pesticides.

Volatile organic compounds (VOCs) emitted by damaged plants convey information to undamaged neighbouring plants, and previous research has shown that these signals are effective over short distances in nature. Many herbivore-induced VOCs react with ozone, which is the most important tropospheric air pollutant in rural areas. We used extrafloral nectar (EFN) secretion as a phenotypic indicator of between-plant communication in Phaseolus lunatus L. (Lima bean) and show that an ozone-rich (80 ppb) atmosphere reduces the distance over which signalling occurs. We found that ozone degrades several herbivore-induced VOCs, a likely mechanism reducing communication distances. Direct exposure to 80-ppb ozone did not affect the VOC emissions from P. lunatus. In addition, we demonstrated that high ozone concentrations, 120 and 160 ppb, induced EFN secretion in exposed plants, whereas more moderate concentrations, 80 and 100 ppb, did not. This suggests that ozone can play a complex role in the indirect defence of P. lunatus.

*Biogenic volatile organic compound (BVOC) emissions from arctic ecosystems are important in view of their role in global atmospheric chemistry and unknown feedbacks to global warming. These cold ecosystems are hotspots of climate warming, which will be more severe here than averaged over the globe. We assess the effects of climatic warming on non-methane BVOC emissions from a subarctic heath. *We performed ecosystem-based chamber measurements and gas chromatography-mass spectrometry (GC-MS) analyses of the BVOCs collected on adsorbent over two growing seasons at a wet subarctic tundra heath hosting a long-term warming and mountain birch (Betula pubescens ssp. czerepanovii) litter addition experiment. *The relatively low emissions of monoterpenes and sesquiterpenes were doubled in response to an air temperature increment of only 1.9-2.5 degrees C, while litter addition had a minor influence. BVOC emissions were seasonal, and warming combined with litter addition triggered emissions of specific compounds. *The unexpectedly high rate of release of BVOCs measured in this conservative warming scenario is far above the estimates produced by the current models, which underlines the importance of a focus on BVOC emissions during climate change. The observed changes have implications for ecological interactions and feedback effects on climate change via impacts on aerosol formation and indirect greenhouse effects.

The individual and combined effects of elevated CO 2 and 0 3 on the foliar chemistry of silver birch (Betula pendula Roth) and on the performance of five potential birch-defoliating insect herbivore species (two geometrid moths, one lymantrid moth and two weevils) were examined. Elevated CO 2 decreased the water concentration in both short- and long-shoot leaves, but the effect of CO 2 on the concentration of nitrogen and individual phenolic compounds was mediated by 0 3 treatment, tree genotype and leaf type. Elevated 0 3 increased the total carbon concentration only in short-shoot leaves. Bioassays showed that elevated CO 2 increased the food consumption rate of juvenile Epirrita autumnata and Rheumaptera hastata larvae fed with short-and long-shoot leaves in spring and mid-summer, respectively, but had no effect on the growth of larvae. The contribution of leaf quality variables to the observed CO 2 effects indicate that insect compensatory consumption may be related to leaf age. Elevated CO 2 increased the food preference of only two tested species: Phyllobius argentatus (CO 2 alone) and R. hastata (CO 2 combined with 0 3 ). The observed stimulus was dependent on tree genotype and the measured leaf quality variables explained only a portion of the stimulus. Elevated 0 3 decreased the growth of flush-feeding young E. autumnata larvae, irrespective of CO 2 concentration, apparently via reductions in general food quality. Therefore, the increasing tropospheric 0 3 concentration could pose a health risk for juvenile early-season birch folivores in future. In conclusion, the effects of elevated 0 3 were found to be detrimental to the performance of early-season insect herbivores in birch whereas elevated CO 2 had only minor effects on insect performance despite changes in food quality related foliar chemistry.

Yeheb is a shrub endemic to the Horn of Africa. It is adapted to hot and xeric environments and known to be resistant to insect herbivores. We analysed volatile organic compounds (VOCs) from the headspace of vegetative branches (VBs) and flowering branches (FBs), stored terpenoids from leaf and bark extracts and foliar total phenolics. Isoprene was the dominant compound in the headspace. In total, 66 VOCs were identified, but only a few stored terpenes were detected. Isoprene and monoterpene emissions from FBs were at levels of 24.0 and 5.12 μg/g dw (dry weight)/h, respectively. A total of 30 compounds were emitted at significantly higher rates from FBs than from VBs. The emission of large quantities of a diverse range of VOCs and the presence of high levels of total phenolics in this plant may be attributed to its defence strategy against both abiotic and biotic stresses in arid environments. Copyright © 2010 John Wiley & Sons, Ltd.

When plants are damaged by herbivorous insects they emit a blend of volatile organic compounds (VOCs) which include a range or terpenoids and green leaf volatiles (GLVs) formed via different metabolic pathways. The precise timing of these emissions upon the onset of herbivore feeding has not been fully elucidated, and the information that is available has been mainly obtained through laboratory based studies. We investigated emissions of VOCs from Populus tremula L. xP. tremuloides Michx. during the first 20 h of feeding by Epirrita autumnata (autumnal moth) larvae in a field site. The study was conducted using Proton Transfer Reaction-Mass Spectrometry (PTR-MS) to measure emissions online, with samples collected for subsequent analysis by complementary gas chromatography-mass spectrometry for purposes of compound identification. GLV emission peaks occurred sporadically from the outset, indicating herbivore activity, while terpene emissions were induced within 16 h. We present data detailing the patterns of monoterpene (MT), GLV and sesquiterpene (SQT) emissions during the early stages of herbivore feeding showing diurnal MT and SQT emission that is correlated more with temperature than light. Peculiarities in the timing of SQT emissions prompted us to conduct a thorough characterization of the equipment used to collect VOCs and thus corroborate the accuracy of results. A laboratory based analysis of the throughput of known GLV, MT and SQT standards at different temperatures was made with PTR-MS. Enclosure temperatures of 12, 20 and 25 degrees C had little influence on the response time for dynamic measurements of a GLV or MT. However, there was a clear effect on SQT measurements. Elucidation of emission patterns in real-time is dependent upon the dynamics of cuvettes at different temperatures.

During 1978–1979 72 species and 9688 individuals of Carabid beetles were collected in cabbage, sugar beet and timothy fields at Viikki, Helsinki. Trechus secalis, Clivina fossor, Amara bifrons, Calathus melanocephalus and Harpalus rufipes were the most numerous species in the total catch. C. fossor in cabbage, Patrobus atrorufus in sugar beet and T. secalis in timothy were the most abundant. The number of carabids was significantly affected by crop plant and year. The diversity of carabids was highest in sugar beet and lowest in timothy. Carabid communities were quite similar in different crops, the highest affinity was between cabbage and sugar beet. Carabid catches were highest during warm and dry periods, especially in cabbage. Meteorological data and activity density patterns in each crop for the eight most numerous species are given. The role of the weather, crop plant and reproduction biology of each species is discussed in relation to abundance and seasonal occurrence. Zusammenfassung Abundanz und saisonales Auftreten adulter Carabidae (Coleoptera) in Kohl-, Zuckerruben- und Timothygrasfeldern im sudlichen Finnland In den Jahren 1978–1979 wurden in Kohl-, Zuckerruben- und Timothygrasfeldern in Viikki, Helsinki, insgesamt 9688 Individuen von 72 Laufkafer-Arten (Carabidae) gefangen. Als haufigste Arten traten Trechus secalis, Clivina fossor, Amara bifrons, Calathus melanocephalus und Harpalus rufipes auf. In den verschiedenen Kulturen waren die dominanten Arten C. fossor (Kohl), Patrobus atrorufus (Zuckerrube) und T. secalis (Timothygras). Je nach Kulturpflanzen und Fangjahren war die Individuenzahl der Laufkafer signifikant verschieden. Die Diversitat (nach Shanon und Weaver) war am hochsten in Zuckerrube und am niedrigsten in Timothygras. Die Laufkafer-Gemeinschaften waren in den verschiedenen Kulturen ziemlich gleichartig. Die Similaritat zwischen den Gemeinschaften war am starksten zwischen Kohl und Zuckerrube. Die Anzahl der gefangenen Laufkafer war am grosten wahrend warmer und trockener Perioden, besonders bei Kohl. Meteorologische und Aktivitats-Diagramme fur die haufigsten 8 Arten werden aufgestellt. Die Rolle des Wetters, der Pflanzenart und der Vermehrungsbiologie von jeder Art in Beziehung zu Abundanz und jahreszeitlichem Auftreten wird diskutiert.

Summary • Does transgenically incorporated insect resistance affect constitutive and herbivore-inducible terpenoid emissions and multitrophic communication under elevated atmospheric CO2 or ozone (O3)? This study aimed to clarify the possible interactions between allocation to direct defences (Bacillus thuringiensis (Bt) toxin production) and that to endogenous indirect defences under future climatic conditions. • Terpenoid emissions were measured from vegetative-stage non-Bt and Bt Brassica napus grown in growth chambers under control or doubled CO2, and control (filtered air) or 100 ppb O3. The olfactometric orientation of Cotesia vestalis, an endoparasitoid of the herbivorous diamondback moth (Plutella xylostella), was assessed under the corresponding CO2 and O3 concentrations. • The response of terpenoid emission to CO2 or O3 elevations was equivalent for Bt and non-Bt plants, but lower target herbivory reduced herbivore-inducible emissions from Bt plants. Elevated CO2 increased emissions of most terpenoids, whereas O3 reduced total terpenoid emissions. Cotesia vestalis orientated to host-damaged plants independent of plant type or CO2 concentration. Under elevated O3, host-damaged non-Bt plants attracted 75% of the parasitoids, but only 36.8% of parasitoids orientated to host-damaged Bt plants. • Elevated O3 has the potential to perturb specialized food-web communication in Bt crops.

Deciduous trees remobilize the nitrogen in senescing leaves during the process of autumn colouration, which in many species is associated with increased concentrations of anthocyanins. Archetti1 and Hamilton and Brown2 observed that autumn colouration is stronger in tree species facing a high diversity of specialist aphids. They proposed a coevolution theory that the bright colours in autumn might provide an honest signal of defence commitment, thus deterring migrant aphids from settling on the leaves. So far, there have been very few experimental results to support the hypothesis, and tree commitment to phenolics-based defences has not shown direct protection against aphids. Predators and parasitoids have been found to be the major controllers of arboreal aphids. Indirect defences involve the emission of attractive volatile compounds that enhance the effectiveness of carnivorous enemies. The indirect defence hypothesis is presented to explain low aphid diversity on tree species that are green during autumn. The hypothesis suggests that green foliage can continue to produce herbivore-inducible plant volatiles and maintain volatile-based indirect plant defences against aphids until leaf abscission. BioEssays 30:889–896, 2008. © 2008 Wiley Periodicals, Inc.

Scots pine [Pinus sylvestris L. (Pinaceae)] trees with four different seed origins were exposed to exogenous applications of the elicitor, methyl jasmonate (MeJA), for three consecutive years. We studied the effects of MeJA on needle chemistry (including monoterpenes, sesquiterpenes, and tricyclic resin acids), plant growth, and the performance of two diprionid sawflies, the European pine sawfly (Neodiprion sertifer Geoffr.) and the common pine sawfly (Diprion pini L.) (both Hymenoptera: Diprionidae). In general, foliar MeJA application affected the whole range of needle secondary chemistry with significantly higher concentrations of two monoterpenes, β-pinene and limonene, in particular. Furthermore, for some seed origins the growth rates of N. sertifer and D. pini larvae were lower on needles of MeJA-treated plants with either high total terpene or high resin acid concentrations. However, inconsistencies in diprionid sawfly performance within each studied Scots pine origin suggest genetic variance in needle secondary chemistry. The differences between selected seed origins and notably variable responses to MeJA application imply that adaptation of the seed to new conditions may have had an impact on secondary chemistry and, thus, on insect performance. Finally, our results suggest that modification of Scots pine defence by a low-concentration exogenous elicitor affects the production of terpenoids in the newly growing needles, leading to poorer pine sawfly performance in origins with high terpenoid content, while not harming the growth of Scots pine trees.

Climate change factors such as elevated carbon dioxide (CO2) and temperature typically affect carbon (C) and nitrogen (N) dynamics of crop plants and the performance of insect herbivores. Insect-resistant transgenic plants invest some nutrients to the production of specific toxic proteins [i.e. endotoxins from Bacillus thuringiensis (Bt)], which could alter the C–N balance of these plants, especially under changed abiotic conditions. Aphids are nonsusceptible to Lepidoptera-targeted Bt Cry1Ac toxin and they typically show response to abiotic conditions, and here we sought to discover whether they might perform differently on compositionally changed Bt oilseed rape. Bt oilseed rape had increased N content in the leaves coupled with reduced total C compared with its nontransgenic counterpart, but in general the C : N responses of both plant types to elevated CO2 and temperature were similar. Elevated CO2 decreased N content and increased C : N ratio of both plant types. Elevated temperature increased C and N contents, total chlorophyll and carotenoid concentrations under ambient CO2, but decreased these under elevated CO2. In addition, soluble sugars were increased and starch decreased by elevated temperature under ambient but not under elevated CO2, whereas photosynthesis was decreased in plants grown under elevated temperature in both CO2 levels. Myzus persicae, a generalist aphid species, responded directly to elevated temperature with reduced developmental time and decreased adult and progeny weights, whereas the development of the Brassica specialist Brevicoryne brassicae was less affected. Feeding by M. persicae resulted in an increase in the N content of oilseed rape leaves under ambient CO2, indicating the potential of herbivore feeding itself to cause allocation changes. The aphids performed equally well on both plant types despite the differences between C–N ratios of Bt and non-Bt oilseed rape, revealing the absence of plant composition-related effects on these pests under elevated CO2, elevated temperature or combined elevated CO2 and temperature conditions.

Transgenic Bt (expressing the cry1Ac endotoxin gene) and conventional oilseed rape plants grown in different soils were used to study nutrient uptake and emission of volatiles after herbivore damage. All plants were greenhouse-grown in soils representing low-, medium- and high-nutrient levels. The concentrations of N, P, K, Mg and Zn were significantly affected by the transgene, while the main effect of soil type appeared in N, P, Ca, Mg, B, Mn and Zn concentrations in the plants. Plants with four to five leaves were infested with the third instar larvae of Bt-susceptible Plutella xylostella for 48 h, and samples of volatiles were collected and analysed. In the first experiment, the soil nutrient level had a significant effect on the emissions of (Z)-3-hexen-1-ol, (Z)-3-hexenyl acetate, hexyl acetate, (E)-4,8-dimethyl-1,3,7-non-atriene (DMNT), beta-elemene, gamma-bisabolene, alpha-bisabolene and (E)-nerolidol. The induction of these volatiles was significantly higher in infested conventional plants grown at a high-soil nutrient level compared to infested conventional plants at a low-soil nutrient level. In the second experiment, the soil nutrient level had a significant effect on the emissions of (Z)-3-hexen-1-ol, (Z)-3-hexenyl acetate and beta-elemene and, again, this was significantly higher in infested conventional plants grown at high-soil nutrient levels in comparison with infested plants at a low-soil nutrient level. In both experiments, the transgene effect was significant on the emissions of DMNT and (E,E)-alpha-farnesene. The differences in emissions between the two separate experiments suggest that growth conditions (particularly daylength) and sampling procedure may affect the ratio of compounds detected in the emission blend, even though the response to herbivory, nutrient availability and the transgene were similar.

Overwintered adult carrot psyllids [Trioza apicalis Forster (Homoptera: Psylloidea: Triozidae)] damage carrot [(Daucus carota ssp. sativum L.) (Apiaceae)] seedlings by phloem feeding on the leaves. The aim of this study was to investigate the carrot root and shoot growth in relation to carrot psyllid density during early growth stages. One, two, or three carrot psyllids were allowed to feed on carrot seedlings for 3 days. Leaf damage was measured at the 8-leaf stage, and root, leaf fresh weight, and number of true leaves were measured at harvest. Both the age of the carrot seedling at infestation and the psyllid density had a significant effect on leaf damage at the 8-leaf stage: seedlings damaged at the cotyledon stage exhibited more leaf damage than seedlings damaged at the 1-leaf stage. A higher psyllid density significantly reduced the carrot root weight at harvest. The significant interaction of psyllid density with seedling age indicates that differently aged carrot seedlings responded differently to feeding: one psyllid feeding for 3 days at the cotyledon stage caused a significant yield loss, whereas three psyllids were needed to cause the same impact at the 1-leaf stage. Carrot leaf weight at harvest was not reduced by carrot psyllid feeding: leaves recovered from the damage but roots did not. Our results confirm the farmers’ observations that a trap replacement period of 1 week for carrot psyllid monitoring is too long, especially at the cotyledon stage. Severe leaf discolouration on damaged carrots was observed at harvest. The possible reasons for this discolouration, such as toxin excreted in psyllid saliva or plant pathogenic mycoplasma infection, are discussed.

Tropospheric ozone levels are continuously rising due to human activities in the 21st century. Although the phytotoxic impact of ozone on plants has been well documented, the effect of ozone on plant emissions has received little attention. We have conducted a field-based investigation utilizing two clones of hybrid aspen (Populus tremula L. ×P. tremuloides Michx.) in a free-air ozone concentration enrichment (FACE) facility. The effects of chronic exposure to moderately increased concentrations of ozone on insect-induced terpene emissions by these trees were investigated. We used two herbivore species, Phyllobius piri, and Epirrita autumnata, both of which can reach outbreak levels on deciduous trees in Northern Europe. Our results indicated only very small changes in emissions due to increased ozone levels, but showed induction of some terpenes, particularly the monoterpene trans-β-ocimene and the homoterpene (E)-4,8-dimethyl-1,3,7-nonatriene, in response to insect feeding. Here, we consider the positive aspects of conducting this type of study in the field and consider the possible influences of other field-based environmental factors.

Isoprene is a reactive hydrocarbon with an important role in atmospheric chemistry, and emissions from vegetation contribute to atmospheric carbon fluxes. The magnitude of isoprene emissions from arctic peatlands is not known, and it may be altered by increasing UV-B radiation. Isoprene emission was measured with the dynamic chamber method from a subarctic peatland under long-term enhancement of UV-B radiation targeted to correspond to a 20% loss in the stratospheric ozone layer. The site type of the peatland was a flark fen dominated by the moss Warnstorfia exannulata and sedges Eriophorum russeolum and Carex limosa. The relationship between species densities and the emission was also assessed. Isoprene emissions were significantly increased by enhanced UV-B radiation during the second (2004) and the fourth (2006) growing seasons under the UV-B exposure. Emissions were related to the density of E. russeolum. The dominant moss, W. exannulata, proved to emit small amounts of isoprene in a laboratory trial. Subarctic fens, even without Sphagnum moss, are a significant source of isoprene to the atmosphere, especially under periods of warm weather. Warming of the Arctic together with enhanced UV-B radiation may substantially increase the emissions.

This paper reports significant effects of a co-occurring plant species (Lythrum salicaria, Lythraceae) on the reproductive success of the perennial herb Filipendula ulmaria (Rosaceae). We studied 1 ...

The effect of atmospheric change on birch aphid (Euceraphis betulae Koch) oviposition preference was examined and plant characteristics that are possibly responsible for the observed effects were investigated. It was hypothesized that the increasing concentrations of CO2 and O3 affect singly or in combination the oviposition of birch aphids via changes in host plant characteristics. Two genotypes of field-growing silver birch (Betula pendula Roth) trees (clones 4 and 80), which were exposed to doubled ambient concentration of CO2 and O3, singly and in combination, in a 3-year open-top chamber experiment, were used in an aphid oviposition preference test. It was found that elevated CO2, irrespective of ozone concentration, increased the number of aphid eggs laid on clone 4, but not in clone 80. Several flavonoid aglycones were identified from the exudate coating of birch buds. Although elevated CO2 and O3 affected these phenolic compounds in clone 4, the effects did not correlate with the observed changes in aphid oviposition. It is suggested that neither bud length, which was not affected by the treatments, nor surface exudate phenolics mediate birch aphid oviposition preference.

Scots pine (Pinus sylvestris L., Pinaceae) produces a terpenoid resin which consists of monoterpenes and resin acids that offer protection against herbivores and pathogen attacks. Methyl jasmonate (MJ) is a potential plant elicitor which induces a wide range of chemical and anatomical defence reactions in conifers and might be used to increase resistance against biotic damage. Different amounts of MJ (control, 10 mM, and 100 mM) were applied to Scots pine to examine the vigour, physiology, herbivory performance, and induction of secondary compound production in needles, bark, and xylem of 2-year-old Scots pine seedlings. Growth decreased significantly in both MJ treated plants, and photosynthesis decreased in the 100 mM MJ treated plants, when compared to 10 mM MJ or control plants. The large pine weevil (Hylobius abietis L.) (Coleoptera: Curculionidae) gnawed a significantly smaller area of stem bark in the 100 mM treated plants than in the control or 10 mM treated plants. The 100 mM MJ treatment increased the resin acid concentration in the needles and xylem but not in the bark. Furthermore, both MJ treatments increased the number of resin ducts in newly developing xylem. The changes in plant growth and chemical parameters after the MJ treatments indicate shifts in carbon allocation, but MJ also affects plant physiology and xylem development. Terpenoid resin production was tissue-specific, but generally increased after MJ treatments, which means that this compound may offer potential protection of conifers against herbivores.

Monoterpenes are plant-based alternatives for pest control in sustainable agriculture. This study investigated the phytotoxic effects of the monoterpene limonene on white cabbage (cv Rinda and Lennox) and carrot (cv Parano and Splendid) plants. The effects of increasing concentrations (from 10 to 120 ml l−1) of limonene on visible leaf injuries, growth, chlorophyll fluorescence, net photosynthesis and stomatal conductance were studied. Limonene concentrations of 90 and 120 ml l−1 were significantly phytotoxic in both cabbage and carrot, depending on the cultivar. However, there were major differences in limonene responses between the cultivars in both species. In carrot, lower shoot and root biomass was related to lower chlorophyll fluorescence (indicating lower efficiency of the photochemical processes) in cv Splendid, whereas in cv Parano it was related to lower stomatal conductance (indicating reduced gas exchange), suggesting that the mechanism behind the phytotoxicity may be different in different cultivars. In cabbage, better limonene tolerance and faster recovery processes in cv Lennox compared with cv Rinda were evident through increasing efficiency of photochemistry (chlorophyll fluorescence), and in the higher stomatal conductance and net photosynthesis rates, providing energy for defence and repair action. Since direct phytotoxic effects were detected on carrot and cabbage with limonene, we conclude that critical threshold concentrations for cultivated plants should be determined before monoterpenes are widely used as repellents and deterrents. These thresholds should, as far as possible, be species- and cultivar-specific in order to provide full protection of plants. Copyright © 2004 Society of Chemical Industry

Elevated atmospheric carbon dioxide (CO2) and ozone (O3) concentrations have both been shown to affect plant tissue quality, which in turn could affect litter decomposition and carbon (C) and nutrient cycling. In order to evaluate effects of climate change on litter chemistry, needle litter was collected from Scots pine (Pinus sylvestris L.) saplings exposed to elevated CO2 or O3 concentration and their combination over three growing seasons in open-top chambers. The decomposition of needle litter was followed for 19 months in a pine forest. During decomposition, needle samples for secondary compound analysis were collected and the mass loss of needles was followed. Main nutrients and total phenolics were analysed from litter in the beginning and at the end of the experiment. After 19-month decomposition, the accumulated mass loss was about 34%; however, no significant differences were found in decomposition rates of needle litter between various treatments. Concentrations of total monoterpenes were about 4%, total resin acids 21% and total phenolics 14% of the initial concentrations in litter after 19-month decomposition. In the beginning of litter decomposition, concentrations of individual monoterpenes –α-pinene and β-pinene – were significantly higher in needle litter grown under elevated CO2. However, concentrations of total monoterpenes during the whole decomposition period were not significantly affected by CO2 or O3 treatments. Concentrations of some individual and total resin acids were higher in needle litter grown under elevated CO2 or O3 than under ambient air. There were no significant differences in concentrations of total phenolics as well as nitrogen (N) and the main nutrient concentrations between treatments during decomposition. High concentrations of monoterpenes and resin acids in needles might slightly delay C recycling in forest soils. It is concluded that elevated CO2 and O3 concentrations do not have remarkable impacts on litter decomposition processes in Scots pine forests.

We propose an alternative hypothesis to the handicap-signalling hypothesis, to explain the high number of specialist aphids on tree species having bright autumn colour. Since birch aphids actively seek the first yellowing leaves for breeding in autumn, it is obvious that autumn colour of foliage does not repel migrating aphids. We suggest that aphids use bright colours as a cue to detect individual trees and leaves that are good sources of nitrogen in the form of amino acids in autumn. The active formation of bright-coloured pigments in leaves is needed to protect them from photo inhibition during energy consuming nutrient retranslocation under cold autumn conditions. During nutrient export from leaves, nitrogen is in the form of amino acids in the sieve elements and easily available for aphids. Therefore, bright colours may act as a signal of easily available high-quality food for viviparous aphid migrants that are selecting suitable trees for their sexual offspring reproduction. The females of sexual generation grown on the better quality food probably can oviposit the over-wintering eggs to the twigs in higher numbers, which may have an adaptive advantage in competition with conspecific females.

1 The carrot psyllid Trioza apicalis and Lygus rugulipennis can cause serious damage to cultivated carrots, especially at the seedling stage. The essential oil composition in leaves of several carrot varieties was studied in relation to oviposition acceptance by sucking insect herbivores that have different feeding strategies. Of the insect species studied, T. apicalis is a carrot specialist, T. anthrisci is an Apiaceae specialist, and L. rugulipennis is a generalist. 2 The oil composition differed significantly between leaves from different carrot varieties (Flakkeer 2, Nantura, Parano, Napoli, Panther, Splendid, Nantes 3 Express). 3 There were no differences in the mean numbers of eggs laid by T. apicalis or T. anthrisci on different varieties, but L. rugulipennis laid fewer eggs on the Panther variety than on Nantes 3 Express. 4 There was a negative linear correlation between limonene concentration and number of eggs laid by T. apicalis, confirming that limonene is a repellent to the carrot psyllid. Results suggest that only particular compounds influence the preference of the carrot psyllid, and these compounds may not be the main components in the essential oil of carrots. 5 A positive correlation was found between myrcene concentration and number of eggs laid by T. anthrisci. Essential oil composition did not explain egg-laying preference of L. rugulipennis. 6 The results indicate that essential oil composition of carrot varieties affects host preference of Apiaceae specialists more than that of generalists.

Terpene, resin acid and total phenolic concentrations in five-year-old Scots pine (Pinus sylvestris L.) seedlings were analysed after exposure to ambient and realistically elevated (2 3 ambient) O3 and CO2 concentrations and their combination in open-top chambers during two growing seasons. Under O3 exposure, limonene concentration in needles and isopimaric concentration in stems decreased significantly. As a response to elevated CO2, a-pinene and total phenolic concentrations in needles increased significantly, while bornyl acetate concentration in needles and palustric + levopimaric and neoabietic acid concentrations in stems decreased significantly. Some terpenes and resin acids were found at lower concentrations in the combined O3 and CO2 treatment than in O3 exposure or elevated CO2. A negative chamber effect was found: seedlings growing inside the chambers with ambient air had significantly lower concentrations of some terpenes and resin acids than seedlings growing outside the chambers. There was a lot of between-tree variation in terpene and resin acid concentrations, which is typical of open-pollinated populations. The results of this study suggest that, at least in shortterm experiments, Scots pine secondary metabolites are relatively insensitive to climate change factors. Total phenolics in the needles were the most responsive group showing about 25% increase in elevated CO2, and O3 exposure did not mitigate this CO2 effect. Terpenes and resin acids were less responsive, although some individual compounds showed notable responses, e.g. a-pinene in needles, which increased about 50% in response to elevated CO2. As a consequence, although there were only slight effects on total pools of needle secondary metabolites, considerable O3 and CO2 effects on certain individual compounds might have ecological significance via trophic amplification, e.g. in decomposing processes of needle litter.

Summary Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies Karst.) seedlings were exposed to realistically elevated O3 levels in open-air experiments over three growing seasons. The total O3 exposure doses were 1.2 × (1991), 1.5 × (1992) and 1.7 × (1993) ambient levels. During the 1992 and 1993 growing seasons pine and spruce seedlings received two different levels of nitrogen supply. Effects on growth, mycorrhiza formation, needle ultrastructure, primary and secondary compounds were studied. Ozone exposure had only slight effects on biomass production, growth height and nutrient content of studied conifers. Higher nitrogen availability improved growth of the seedlings and resulted in higher concentration of nitrogen in needles. In Scots pine O3 exposure did not have effects on quantity of total mycorrhizas and short roots, while higher nitrogen availability decreased quantity of mycorrhizas and short roots. In both tree species O3 exposure induced O3-related ultrastructural symptoms, e.g. granulation and dark staining of the chloroplast stroma in the needle mesophyll cells, at both nitrogen availability levels. Ozone exposure and nitrogen availability did not have significant effects on starch concentrations in either tree species. Concentrations of some individual terpenes were higher in O3-exposed needles, while concentrations of individual and total resin acids, total phenolics and catechins were not affected by O3 exposure. Nitrogen availability did not have substantial effects on concentrations of monoterpenes. By contrast, concentrations of some individual and total resin acids were lower in pine needles and higher in spruce needles with higher nitrogen availability, while phenolic concentration in spruce needles decreased at higher nitrogen availability. The results suggest that realistically elevated levels of O3 in the field can have some negative effects on the mesophyll ultrastructure of conifer needles, but carbon allocation to root and shoot growth and secondary metabolites are not affected substantially.

The effects of low-level ozone exposure and suppression of natural mycorrhizas on the above-ground chemical quality of Scots pine (Pinus sylvestris L.) needles and insect herbivore performance were studied in a two-year field experiment. Seedlings were fumigated with the ozone doses 1.5–1.7 times the ambient, and natural mycorrhizal infection level was about 35% reduced in roots with fungicide propiconazole. On ozone-exposed seedlings the mean relative growth rate (MRGR) of Lygus rugulipennis Popp. nymphs was lower than on ambient ozone seedlings, but Gilpinia pallida Klug sawfly larvae grew better on elevated ozone seedlings than on ambient ozone seedlings. MRGR of Schizolachnus pineti Fabr. and Cinara pinea L. aphid nymphs or Neodiprion sertifer Geoffr. sawfly larvae or the oviposition of L. rugulipennis and N. sertifer were not affected by ozone exposure. Although ozone exposure did not affect total phenolics, total terpene, total or individual resin acid, total free amino acid, nutrient or sugar concentrations in needles, MRGR of L. rugulipennis positively correlated with total terpenes and MRGR of G. pallida positively with total amino acids. In addition, ozone exposure increased serine and proline concentration and marginally also starch concentration in needles. When mycorrhizas were reduced with fungicide, only MRGR of L. rugulipennis nymphs increased, but performance of other insect herbivores studied was not changed. However, number of L. rugulipennis eggs correlated positively with mycorrhizal infection level and also with total sugars. Reduction of mycorrhizas did not strongly affect the concentrations of analysed compounds in needles, because only phosphorus and potassium and some individual resin acids were reduced by fungicide treatment. These results suggest that low-level ozone exposure and moderately declined mycorrhizal infection do not drastically affect either the above-ground chemical quality of Scots pine seedlings or performance of studied insect herbivores. (Less)

Combined effects of O{sub 3} and N supply on Scots pine (Pinus sylvestris L.) were studied in two separate growth chamber experiments exposing seedlings to 0, 0.075, 0.15, and 0.3 {micro}L/L of O{sub 3} during 8 h/d, 5 d/wk for a period of 5 wk. Seedlings were fertilized with low, medium, and high levels of N. Ozone and N availability affected concentrations of several primary and secondary metabolites. More changes on metabolites were detected in Exp. 1 (with seedlings ceasing their annual growth) than in Exp. 2 (with seedlings actively growing). Overall, high O{sub 3} exposure levels significantly decreased concentrations of monoterpenes and increased concentrations of resin acids. Concentrations of total phenolics were not affected by O{sub 3} exposure. Mostly lower concentrations of monoterpenes and resin acids were found at a medium N-fertilization level than at low and high N-fertilization levels, while total phenolic concentration decreased by enhanced N availability. In Exp. 1, significantly elevated concentrations of free amino acids were found at O{sub 3} concentration of 0.3 {micro}L/L. Nitrogen availability did not have remarkable effects on amino acid concentrations. In Exp. 1, both {sub 3} and N had a significant effect on the MRGR of the aphid Schizolachnus pineti.more » In Exp. 2, the weight of the females and nymphs and the total number of reproduced nymphs were significantly affected by O{sub 3} and N. Only a few interaction effects were found, suggesting that the N supply does not significantly modify O{sub 3}-induced effects on studied primary and secondary compounds and aphid performance in Scots pine seedlings.« less

SUMMARY We tested how nitrogen availability affects suitability of ectomycorrhizal (ECM) and non-mycorrhizal Pinus sylvestris (L.) for a polyphagous insect herbivore. Seedlings grown on sterile agar at two N levels, were infected or not with the ECM fungus Cenococcum geophilum (Sow.) Ferd. & Winge. Ultrastructural observations showed that C. geophilum formed well-developed ectomycorrhizas in pine roots. After mycorrhizal establishment, oviposition preference of the polyphagous tarnished plant bug (Lygus rugulipennis Popp.) was determined in three different experiments. The duration of these experiments and the amount of irradiance were different. Nitrogen level or mycorrhizal treatment did not have significant effects on oviposition preference. However, mycorrhizal seedlings were favoured as an oviposition site at the lower N level, but only in expt 1. Total or individual terpene, total resin acid and total or individual sugar concentrations in pine shoots were not altered by treatment. Total phenolics concentration in pine shoots and roots was also the same in different treatments. Of individual resin acids, the concentration of dehydroabietic acid was increased after mycorrhizal treatment. Total resin acid, abietic acid and sandaraco pimaric acid concentrations correlated negatively with the number of Lygus eggs, but the correlations were only marginally significant. Of individual terpenes, ,8-pinene and bornylacetate concentrations had a significant positive correlation with the number of Lygus eggs. Greater amounts of N predictably increased total N concentration in pine seedlings in expts 1 and 2, but mycorrhizal infection increased total nitrogen concentration only in expt 3. Total N concentration did not correlate with the number of Lygus eggs in expts 1 and 2. An early stage of mycorrhizal development did not provide mycorrhizal benefits to the host plant as a higher nutrient concentration or as increased growth. These results suggest that host-plant quality might be involved in selection of oviposition site by L. rugulipennis, but ectomycorrhizal infection at this level does not seem to be an important mediator.

Spruce shoot aphid, Cinara pilicornis Hartig (Homoptera: Lachnidae), is an aphid species that has shown enhanced performance on trees exposed to SO 2 or mixtures of air pollutants, whereas results with ozone have been contradictory. Using a 4-week chamber fumigation experiment, we tested how different population dynamic parameters of aphids are affected by ozone (O 3 ). Mean relative growth rate (MRGR), development time and reproduction rate of C. pilicornis were determined using 7h day-time O 3 concentrations of 0, 40, 80 and 160 ppb. Development period from birth to reproductive stage was fastest at 80 ppb during early shoot elongation, while reproduction and intrinsic rate of population increase was not significantly affected by ozone concentration. There was a significant negative correlation between ozone concentration and the MRGR of first instar nymphs in the third fumigation week. In feeding test performed on seedlings after fumigation, the MRGR was reduced on shoots which had been exposed to 80 ppb O 3 . The results suggest that elevated O 3 concentration during early shoot elongation period may stimulate population development of C. pilicornis, but on maturing shoots, high O 3 concentration has a negative effect on aphid performance. This might be due to accelerated ageing of O 3 exposed shoots.

The phenology of Fagus sylvatica was unaffected by exposure to an atmosphere of elevated CO2 (600 μL L-1) after two years of fumigation. Non-significant changes in nitrogen and phenolic content of the leaves decreased the nutritional status of beech for female larvae in elevated CO2 such that they responded by eating in a compensatory manner; males were unaffected. Rates of development, mortality and adult biomass of Rhynchaenus fagi were no different from those in ambient CO2 concentrations (355 μL L -1). It is possible that, with the changes in leaf chemistry affecting the females, fecundity will be altered, with important consequences for populations of beech weevil.

Needle damages caused by mining insects on Scots pine and Norway spruce were studied in the vicinity of a pulp mill. The abundance of needles mined by the pine bud moth Exoteleia dodecella (Lepidoptera: Gelechiidae) on Scots pine Pinus sylvestris and the spruce needle miner Epinotia tedella (Lepidoptera: Tortricidae) on Norway spruce Picea ahies had a significantly peaked response curve on logarithmic distance scale. For pine bud moth, the maximum expected population density was estimated to be at the distance of 1.35 km from the factory. The maximum expected population density for the spruce needle miner was at the distance of 1.53 km from the factory. However, for both species the curves were significantly different among transects. Both species had a peaked and significant response to sulphur level in needles as well. The maximum expected density in pine was at 1270 ppm, and in spruce at 1070 ppm sulphur concentration in pine needles. The results are consistent with earlier reports demonstrating that these mining insects frequently attack trees suffering from air pollution. The nonlinear response of both species to distance from the pulp mill suggests that E. dodecella on pine and E. tedella on spruce are rather indicators of the zone of intermediate air pollution than of strongly polluted or nearly unpolluted sites. This also agrees with the plant stress-insect performance hypothesis indicating that insect response varies with the magnitude of stress, and at very high stress levels a tree no longer provides the insects with relevant food.

We tested how variable nitrogen availability affects the above-and below-ground growth of first-year Scots pine (Pinus sylvestris L.) seedlings and carbon allocation to defensive allelochemicals and storage. Concentrations of free ammo acids were considered as indicators of nutritive quality. Suitability of seedlings for polyphagous Lygus rugulipennis Popp. (Heteroptera: Miridae) was tested with oviposition preference and nymphal growth experiments. At the end of the growing season, needle length increased while root hiomass decreased with elevated N fertilization, but shoot length was not affected. Concentration of starch in needles and roots, representing carbon storage, was not significantly affected by N fertilization, although there was a decrease in the starch concentration of needles when nitrogen input increased. Nitrogen fertilization significantly increased the pool of total and non-essential ammo acids in the shoots. Arginine, proline and glutamine were the individual ammo acids most affected by elevated N. Of the carbon-based defence compounds, total resin acid concentrations in shoots were significantly reduced with elevated nitrogen in 9-wk-old seedlings. Palustric acid and neoabietic acid were the most affected individual) resin acids, where as foliar monoterpenes were not influenced by N availability. Total phenolics in shoot and root showed variable response. The increasing effect of nitrogen on the oviposition rate of Lygus females was almost linear. Mean relative growth rate of the nymphs was significantly affected by the level of N fertilization. but the mortality of nymphs was high in all treatments. The results suggest that in nitrogen-rich environments the needle growth of small Scots pine seedlings is improved, but their Susceptibility to insect attack is increased and they remain less defended as predicted by the carbon/nutrient balance hypothesis. Total phenolics and resin acids, representing phenylalanine and mevalonic acid pathways, respectively, were both reduced by increased nitrogen availability. Together with the simultaneous increase of foliar free nitrogen in the form amino acids, the nutritive value of seedlings is ameliorated and this might explain susceptibility of nursery-grown. N fertilized seedlings to polyphagous Lygus bugs.

SUMMARY In a search for biochemical markers indicating the impact of ozone on plants. Pathogenesis related (PR) proteins were studied. The following observations were made: (1) PR-proteins are present in gymnosperms, exemplified by Norway spruce (Picea abies) and (2) ozone induces PR-proteins in Norway spruce. Studies were made by Western blot analysis using antibodies raised against seven PR-proteins; five from tobacco (PR-1a, -1b, -1c, -P and -Q) and two from maize (PRm 6 and 7). Each antibody recognized specific proteins in spruce needles. A more detailed study was done with the antibodies against tobacco PR-P (endochitinase) and maize PRm 6 (β-1,3-glucanase). Exposure to ozone increased the contents of proteins recognized by both antibodies. In control trees, anti-PR-P antibody recognized a protein of about 28 kD while in the ozone-exposed trees a form with a slightly faster migration rate in SDS-PAGE predominated. In contrast, in the range of 34–44 kD, a family of proteins was recognized by anti-PRm 6 antibody upon induction by ozone. In this same size range, a strong bund of 37 KD appeared in the total protein pattern, corresponding to about 5 to 10% of total protein. N-terminal sequencing revealed a typical homology pattern shared by β-1,3-glucanases. This was also reflected by the enzymatic level Where ozone was shown to increase β-1,3-glucanase activity. By inducing pathogenesis-related proteins, ozone may modify the response of spruce to pathogens.

Literature regarding the host plants of the European tarnished plant bug (Lygus rugulipennis Poppius) is surveyed and records of some unpublished host plants are added. The recorded hosts include 437 plants from 57 families. Of these 50 host plants are classified to genus and 387 to species or subspecies level. Oviposition of L. rugulipennis or growth of its nymphs has been observed on 59 plant species. The most important host families are Brassicaceae, Asteraceae and Fabaceae. The highest total numbers of recorded host plants are from Poland, Finland and France. Damage to crop plants caused by L. rugulipennis has been most often recorded on alfalfa, clover, potato, cereals and sugarbeet. L. rugulipennis probably has the broadest documented host plant range after Philaenus spumarius (L.) (Horn., Cercopidae), which has nearly 500 documented host plant species. The distribution and attractiveness of different hosts is discussed. Zusammenfassung Wirtspflanzen der Truben Feldwanze, Lygus rugulipennis Poppius (Het., Miridae) Es wird ein Literaturuberblick uber das Wirtspflanzenspektrum von Lygus rugulipennis gegeben, das durch einige unveroffentlichte Wirtspflanzenangaben erganzt wird. Es konnten 437 Wirtspflanzen aus 57 Familien ermittelt werden. Von diesen sind 50 Wirtspflanzen bis zur Gattung, 387 bis zur Art oder Unterart bestimmt. An 59 Pflanzenarten konnte eine Eiablage oder die Entwicklung der Nymphen beobachtet werden. Die wichtigsten Wirtspflanzen gehoren zu den Familien Brassicaceae, Asteraceae und Fabaceae. Die groste Wirtspflanzenzahl wird aus Polen, Finnland und Frankreich gemeldet. Schaden an Nutzpflanzen durch L. rugulipennis wurden uberwiegend an Luzerne, Klee, Kartoffeln, Getreide und Zuckerruben festgestellt. Neben Philaenus spumaris (L.) (Horn., Ceropidae), dessen Wirtspflanzenspektrum nahezu 500 Pflanzenarten umfast, hat L. rugulipennis das wohl breiteste dokumentierte Wirtspflanzenspektrum. Die Verbreitung und Attraktivitat der verschiedenen Wirte wird diskutiert.

Carabid beetles were sampled using pitfall traps on 3 biologically and 4 conventionally managed cabbage fields near Frankfurt, FRG, during 2 growing seasons. The total carabid catch was 4541 individuals representing 54 species. Of the 10 most abundant species Pterostichus melanarius, P. cupreus, Loricera pilicornis, and Agonum dorsale were significantly more abundant in biologically managed fields, whereas Trechus quadristriatus, Bembidion quadrimaculatum, and B. lampros were more abundant in conventionally managed fields. The total biomass of captured carabid beetles was in biologically managed fields significantly higher (about 2–20 times) than in conventionally managed fields throughout the summer. The higher carabid activity density in biologically managed fields was probably due to the more abundant soil fauna and other sources of prey. More carabid species were found on biologically than in conventionally managed fields, but no significant difference in the species diversity index was detectable. Based on dominance similarity comparisons between the studied fields, the method of farming seemed to modify annually the carabid fauna to be indicative of the practiced farming method. Zusammenfassung Laufkaferarten und ihre Aktivitatsdichte auf biologisch und konventionell bewirtschafteten Kohlfeldern Wahrend 2 Anbauperioden wurde die Laufkaferfauna auf 3 biologisch und 4 konventionell bewirtschafteten Weiskohlfeldern in der Nahe von Frankfurt am Main, BRD, mit Hilfe von Pitfallfallen untersucht. Die Gesamtzahl der gefangenen Individuen betrug 4541, die 54 verschiedene Arten reprasentierten. Von den 10 am haufigsten aufgetretenen Arten waren Pterostichus melanarius, P. cupreus, Loricera pilicornis und Agonum dorsale signifikant zahlreicher auf biologisch bewirtschafteten Feldern, wohingegen Trechus quadristrichatus, Bembidion quadrimaculatum und B. lampros signifikant haufiger auf konventionell betriebenen Feldern vorkamen. Auf biologisch bewirtschafteten Feldern lag die Gesamtbiomasse der Laufkafer ebenfalls signifikant hoher (2–20mal) als auf konventionell bewirtschafteten Feldern. Die hohere Laufkaferaktivitatsdichte auf biologisch bewirtschafteten Feldern durfte auf die vielfaltigere Bodenfauna und auf andere weitere Nahrungsquellen zuruckzufuhren sein. Obwohl ein groserer Artenreichtum auf biologisch betriebenen Feldern als auf konventionell bewirtschafteten festgestellt wurde, konnte kein signifikanter Unterschied im Artendiversitatsindex nachgewiesen werden. Dominanzsimilari-tatsvergleiche zwischen den Untersuchungsfeldern deuten darauf hin, das die Laufkaferfauna jahrlich von der Bewirtschaftungsmethode charakteristisch modifiziert wird.

The oviposition host preference of the tarnished plant bug (Lygus rugulipennis Popp.) and occurrence of this species on stocks of conifers, silver birch and on a common weed, Senecio vulgaris in a conifer nursery were studied. In the nursery adults and nymphs of the bug were more abundant on S. vulgaris and Silver birch than on conifer seedlings in July and August. In cage experiments S. vulgaris and Stellaria media were the most preferred oviposition hosts among 3 woody and 9 herbaceous species tested. The greater attractiveness of herbaceous plants may offer the possibility of using these plants as trap plants around nursery stocks of conifers during oviposition period of L. rugulipennis to decrease the damage caused by this bug on conifer seedlings. Zusammenfassung Zur Wirtspflanzenpraferenz der Truben Feldwanze, Lygus rugulipennis Popp. (Het., Miridae) In einem Koniferenpflanzgarten wurde untersucht, welche Wirtspflanzen Lygus rugulipennis zur Eiablage bevorzugt, und es wurde das Vorkommen von L. rugulipennis auf Koniferenpflanzen, auf Silberbirke sowie auf Senecio vulgaris untersucht. Im Pflanzengarten waren im Juli/August Adulte und Nymphen haufiger auf S. vulgaris und auf Silberbirke zu finden als auf Koniferensamlingen. In Kafigversuchen erwiesen sich S. vulgaris und Stellaria media von 12 getesteten Pflanzen (9 krautige Gewachse und 3 Holzgewachse) als die bevorzugtesten Pflanzen zur Eiablage. Die grosere Attraktivitat von krautigen Pflanzen scheint die Moglichkeit zu bieten, diese Pflanzen wahrend der Eiablagezeit der Wanze als Fangpflanzen in Koniferenpflanzgarten zu nutzen, um die Schaden, die L. rugulipennis an Koniferensamlingen verursacht, zu reduzieren.

The effects of simulated summer night frost on actively growing Scots pine seedlings were studied in environmental plant growth chambers. Exposure to temperatures ranging from −4.5°C to −7.5°C caused ultrastructural alterations in the mesophyll cells of visually healthy cotyledons and primary needles of pine seedlings.

Carabid beetles were monitored with pitfall traps in cabbage, sugarbeet and timothy fields in two successive growing seasons. Enclosure of the trapping areas with a polythene barrier decreased the total carabid catches highly significantly, especially the numbers of large and medium-sized species. The catches of several small macropterous and dimorphic carabid species (e.g. Bembidion quadrimaculatum, Clivina fossor, Trechus quadristriatus, T. discus, T. micros) were not affected to the same extent. The use of formalin in the traps increased the total carabid catches, but Amara bifrons was the only single species whose numbers were significantly raised. In studies made to examine the effect of carabid predation on prey populations, enclosure of study plots with polythene barriers does not decrease the catches of the different species to the same extent, which may lead to difficulties in the evaluation of their predatory role. Zusammenfassung Uber den Einflus mechanischer Barrieren und Formalinlosung auf die Bodenfallenfange von Laufkafern (Coleoptera, Carabidae) auf Ackerland Das Auftreten der Laufkafer in Kohl-, Zuckerruben- und Timothygrasfeldern wurde in zwei aufeinanderfolgenden Jahren mit Hilfe von Bodenfallen untersucht. In den durch Polyathylenbarrieren begrenzten Fanggebieten waren die Totalfange der Laufkafer signifikant reduziert. Besonders deutlich wurde die Abundanz von grosen und mittelgrosen Arten beeinflust im Vergleich zu manchen kleinen makropteren und dimorphen Arten (z.B. Bembidion quadrimaculatum, Clivina fossor, Trechus quadristriatus, T. discus, T. micros). Die Totalfangzahlen waren hoher in Fallen mit Formalin als Konservierungsflussigkeit als in leeren Fallen. Amara bifrons war jedoch die einzige Art, deren Individuenzahl signifikant anstieg. Zum Einflus der rauberischen Tatigkeit der Laufkafer auf die Beutepopulationen wurde festgestellt, das die Polyathylenbarriere die Fange von verschiedenen Arten nicht gleichmasig reduzierte. Dies kann die Beurteilung der rauberischen Wirkung der Laufkafer komplizieren.

Summary Laboratory experiments were carried out to evaluate the efficiency of two insecticides, cypermethrin and oxydemeton-methyl, in controlling the nymphs and adults of Lygus bugs and the resulting damage caused by these bugs to small pine seedlings. Both insecticides significantly increased the mortality of bugs on the seedlings compared with bug mortality on untreated controls. Mortality of bugs was higher in the oxydemeton-methyl treatment than in the cypermethrin treatment. The occurrence of seedlings with multiple leaders and the number of leader shoots per seedling were significantly decreased in insecticide-treated seedlings. Mean number of leader shoots was significantly higher in seedlings treated with oxydemeton-methyl than in seedlings treated with cypermethrin after a 24-h exposure to nymphal instars of Lygus. The mortality of the pine seedlings was very low but significantly decreased in insecticidal treatments. Factors affecting the effects of different insecticides on bug mortality and their efficiency in controlling the multiple-leadering phenomenon are discussed.