PLANTS AND INSECT CHEMICAL ECOLOGY

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Aspects of insect chemical ecology: exploitation of reception and detection as tools for deception of pests and beneficial insects

Aspects of insect chemical ecology: exploitation of reception and detection as tools for deception of pests and beneficial insects

By investigating and understanding host location, approaches to deterring pest aphids can be discovered (Bruce & Pickett, 2011). However, rather than using a repellent mixture of com- pounds applied to the crop, host recognition could be disrupted by altering the composition of mixtures released by the plant, or by adding nonhost specific compounds using GM and even plant breeding, although the latter would probably only apply to changing mixture composition. The biosynthesis of some such semiochemicals is already known, as are the associated genetics, presenting a potential target for this new type of pest resistance in crop plants. Another opportunity for ‘repelling’ aphids by GM was also proposed (Pickett, 1985) and was achieved in the model plant Arabidopsis thaliana, genetically transformed with a gene for synthesizing (E)- β -farnenese, the alarm pheromone for many pest aphids (Beale et al., 2006). These A. thaliana plants expressed a gene for the synthesis of pure (E)- β -farnenese, with this being necessary to avoid aphid alarm pheromone inhibitors such as the (1R,4E,9S)- caryophyllene produced naturally by plants (Dawson et al., 1984; Bruce et al., 2005). Transformed plants were found to be ‘repellent’ to the peach-potato aphid Myzus persicae, as well as to cause increased foraging by the aphid parasitoid Diaeretiella rapae (Beale et al., 2006). Furthermore, trans- formation with an (E)- β -farnenese synthase gene has now been achieved in an elite wheat variety, Cadenza, using more sophisticated molecular methods. The transformed wheat elic- its similar aphid ‘repellency’ and increased parasitoid foraging behaviour in the laboratory (T. J. A. Bruce, unpublished data), and permission has now been obtained from the U.K. Govern- ment Advisory Committee on Releases to the Environment for field trials commencing in 2012.
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Chemical ecology of insect parasitoids: towards a new era

Chemical ecology of insect parasitoids: towards a new era

Semiochemical-based manipulations normally include either ‘pheromone-based tactics’ or ‘allelochemical-based tactics’. Pheromone-based tactics now represent one of the major strategies in ecologically based orchard pest management, leading to considerable success in both direct and indirect insect pest control. The most successful applications for the direct control of pest populations concern the release of sex pheromones to disrupt mating in the target pests ( Witzgall et al . 2010 ). In contrast, allelochemical-based tactics represent a relatively new approach that mainly uses plant volatiles. The most promising application of allelochemical-based tactics involves the use of herbivore-induced plant volatiles (HIPVs) to manipulate the natural enemies of the pest species in order to attract and conserve them in the vicinity of the crops to be protected. HIPVs are semiochemicals that mediate many multitrophic interactions in both above- and below-ground plant–insect communities ( Soler et al . 2007 , Soler, Bezemer & Harvey, Chapter 4 , this volume). These volatiles have received increased attention for their role in attracting natural enemies of insect pests (Ode, Chapter 2 , this volume). In the last decade, the results of several fi eld experiments have been published demonstrating that the release of HIPVs can indeed augment, conserve or enhance the effi cacy of natural enemies. However, allelochemical-based tactics, especially based on the use of HIPVs, are lagging far behind the development of applications of pheromones. In this respect, it has to be noted that genetically modifi ed plants have recently been shown to provide new opportunities for semiochemical applications. For example, plants can be engineered to produce ( E )- β -farnesene to mimic the natural aphid alarm response in order to increase foraging by aphid predators and parasitoids ( Yu et al . 2012 ).
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Chemical Cues in Tritrophic Interaction on Biocontrol of Insect Pest

Chemical Cues in Tritrophic Interaction on Biocontrol of Insect Pest

The use of volatiles compound extracted from plants for parasitoid attractant has not been intensively developed in pest management. Meanwhile, this previous research has proven that volatiles produced by a plant as its reaction to a specific way of herbivore infestation were used by specific parasitoids as a cue for host location. Therefore, the volatiles could be a high specificity cues for biocontrol agents. Developing such volatiles for parasitoid attractant would need an understanding both insects ecology as well as chemical ecology in tritrophic interactions. The volatiles for attractant could be developed by involving volatile adsorbent in the attractant formulation.
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Alternatives to Chemical Control of Insect Pests

Alternatives to Chemical Control of Insect Pests

Crop culture sets the stage for interactions between plants, pests, and natural enemies, and has a strong influence on the outcome of these interactions. In many cases, implementing effective cultural controls can be the most economical pest management tactic available to growers because labor and expense are incurred regardless of whether an effective cultural tactic is used. Understanding and implementing cultural practices can reduce other production expenses such as insecticides and fertilizer. Cultural control can be compatible with biological control if the myriad interactions among plants, pests, and natural enemies are well defined. Improving the predictability of biological control will rely on elevating the discipline to its proper place in applied evolutionary ecology and further refinement of the art and practice of biological control (van Lenteren, 1980; Heinz et al., 1993; Heinz, 2005). Fortunately, the organic and sustainable agriculture movements that are gaining both societal and political momentum seem to embrace the art and science of biological pest control (Edwards, 1990; Raynolds, 2000). While various physical control techniques have been used successfully in production systems, this strategy is limited by the significant labor, time, cost, and specialization required for successful control (Vincent et al., 2009). Further refinements and developments in physical control technologies hold promise for enhanced efficacy, compatibility with cultural and biological control, and profits.
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The ecology of subindividual variability in plants: patterns, processes, and prospects

The ecology of subindividual variability in plants: patterns, processes, and prospects

Within-plant variation in leaf, flower, fruit, or seed charac- teristics can affect diverse aspects of plant vegetative (e.g., growth rate, carbon assimilation) and reproductive (e.g., fe- cundity) performance of individuals, as shown by signifi- cant correlations across plants between subindividual vari- ability and diverse measurements of individual performance (Herrera, 2009). In the case of leaves, it has been frequently suggested that subindividual variation in some of their func- tional traits may be advantageous to individuals by enhanc- ing whole-plant photosynthetic performance and optimiz- ing the exploitation of environmental variation (e.g., canopy light gradients; Givnish, 1988; Hollinger, 1996; Osada et al., 2014). For the perennial herb Helleborus foetidus, Herrera et al. (2015) suggested that variation in size, specific leaf area, and stomatal traits across leaves borne in different nodal po- sitions along ramets could influence the water economy and carbon assimilation efficiency of whole plants, and suggested possible mechanisms in support of this explanation. Indirect support for their interpretation is provided by the significant relationships existing across individuals between seed fecun- dity and within-plant leaf variability (Fig. 5). The broad dif- ferences between individuals in subindividual variability of stomatal index, stomatal density, stomatal length, and spe- cific leaf area illustrated in Fig. 4 collectively account for 13 % of the variance in seed fecundity (Fig. 5). The higher the within-plant variability in stomatal index, stomatal length, and specific area, and the lower the variability in stomatal density, the higher was the total number of seeds produced by individual plants, perhaps as a consequence of improved water economy and/or carbon assimilation. Relationships be- tween subindividual variability and fecundity can also hold across populations of the same species, as exemplified by the significant nonlinear relationship between mean individual fecundity and mean subindividual variability in specific leaf area across the populations of Helleborus foetidus sampled by Herrera et al. (2015) (Fig. 6).
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Insect. Pests OF RICE. M. D. Pathak and Z. R. Khan ICIPE. International Centre of Insect Physiology and Ecology

Insect. Pests OF RICE. M. D. Pathak and Z. R. Khan ICIPE. International Centre of Insect Physiology and Ecology

In general, stem borers are polyvolt- ine, but the number of generations in a year depends on environmental factors, primarily temperature, rainfall, and crop availability. In different geographical areas, the borers hibernate, aestivate, or remain active throughout the year, and occur in different seasonal patterns. In areas of short optimum environmental conditions, such as in northern Japan, they appear in only one generation; in Central Japan and the Republic of Korea, in two generations; and in most of the comparatively warm places with a single rice cropping regime, in three to four generations. are frequently referred to as respec- tive broods. During periods when there is no rice crop and the tempera- tures are not optimum for larval development, the full-grown larvae undergo dormancy or diapause. But wherever two or more rice crops are grown in a year, the borers remain active year-round, undergoing only a temporary quiescent stage or weak diapause in the last larval instar during brief periods of nonavailabil- ity of host plants. This is apparently true for most tropical rice where moths have been caught in light traps throughout the year. Their popula- tion peaks have often been misinter- preted as different broods. A critical evaluation of the data shows that these peaks in light trap catches are reflections of major planting seasons and brief environmental variations rather than distinct seasonal effects.
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Insect and Mite Control Options for plants grown in Wyoming Greenhouses

Insect and Mite Control Options for plants grown in Wyoming Greenhouses

The University of Wyoming is an affirmative action/equal opportunity employer and institution and does not discriminate on the basis of race, color, religion, sex, national origin, disa[r]

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Evaluation of Botanical Mixtures for Insect Pests Management on Cowpea Plants

Evaluation of Botanical Mixtures for Insect Pests Management on Cowpea Plants

Plant based insecticides (PBI) have been used for many centuries ( Jacobson , 1958, 1975) among limited resource farmers in developing countries to control insect pests of both field crops and stored produce, but their potential was initially limited and ignored. Nicotine, rotenone and pyrethrum were popular among the PBIs used to some extent for storage pests control and other pests in green houses ( Schmutterer , 1981).Some of these plant species possess one or more useful properties such as repellency, antifeedant, fast knock down, flushing action, biodegradability, broad-spectrum of activity and ability to reduce insect resistance ( Olaifa et al., 1987; Stoll , 1988).However, most of them are either weak insecticidally or may require other plant species with different mode of action (depending on the ratio and rate of application) to increase their potency ( Sommers , 1983; Oparaeke , 2004).For instance, Xylopia aethiopica (Dunal) (A. Rich.) is found to be weak insecticidally for control of Callosobruchus maculatus Fab.on bruchid ( Oparaeke , 1997; Oparaeke and Bunmi , 2004) and on field pests of cowpea ( Oparaeke , 2004).However, ground, dried fruit of X. aethiopica (African pepper or
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The Population Ecology of Ant-dispersed Plants in Space and Time.

The Population Ecology of Ant-dispersed Plants in Space and Time.

Much of ecology seeks to understand interactions among species and their consequences. Evidence continues to grow that facilitation, and more specifically mutualism, increases biological diversity and shapes the structure of ecological communities (Stachowicz 2001; Bruno et al. 2003; Lengyel et al. 2009). In particular, ant-seed dispersal mutualisms (myrmecochory) are both geographically widespread and ecologically important (Giladi 2006; Lengyel et al. 2010). Myrmecochorous seeds have a small, lipid-rich appendage called an elaiosome that ants remove and consume after dispersal. Elaiosomes have evolved tens of times in the monocots (Dunn et al. 2007) and over a hundred times in the angiosperms more generally (Lengyel et al. 2009; Lengyel et al. 2010). Over 11,000 species and 77 families of angiosperms participate in myrmecochorous relationships across a variety of ecosystems that span arid, tropical, and temperate regions (Giladi 2006; Lengyel et al. 2010). To date, our understanding of the benefits of myrmecochory to plants (reviewed in Giladi 2006) focus on dispersal distance of the seed away from its parent (e.g., Andersen 1988), reduction in seed predation due to dispersal (e.g., Culver and Beattie 1978; Heithaus 1981) and movement of the seed to a favorable germination site (e.g., Beattie and Culver 1983; Hanzawa et al. 1988).
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The reproductive ecology of vascular plants on subantarctic Macquarie Island

The reproductive ecology of vascular plants on subantarctic Macquarie Island

As such the subantarctic islands represent the southern limit of many vascular plant families and genera, as well as relatively complex vascular plant dominated plant communities.. Sever[r]

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Chemical ecology and conservation biogeography of Rhododendron ponticum L

Chemical ecology and conservation biogeography of Rhododendron ponticum L

tw o species w ere collected from populations o f R. ponticum , w hile the la tte r was reared fro m larval stage in a glasshouse on straw berry plants. However, as Nut leaf and Clay-coloured weevils refused to feed on artificial diets (see below) during initial trials, fu rth e r experim ents w ith these species w ere not attem pted . Bioassays w ith black vine weevils (BVWs) w ere conducted using late instar adults in pre-oviposition period; a phase lasting 3-6 weeks during which tim e they consume the most plant foliage. T hirty adults were placed in to individual arenas (20 X 10 X 6 cm) and random ly allocated to three treatm ents: 1.) a control artificial diet; 2.) an artificial diet in which GTX I was incorporated at natural leaf concentrations; and 3.) an a rtificial diet in which ten tim es the natural concentrations o f GTX I was incorporated. A rtificia l diets fo r BVWs w ere constructed follo w in g established techniques (Bristow et al. 1979, Shanks and Doss 1987), which consisted o f cellulose acetate disks (0.45 nm pore size) tre a te d w ith water-dissolved sucrose and p-sitosterol phagostim ulants at concentrations known to solicit high feeding rates (Doss and Shanks 1984). Sample sizes (the num ber o f BVWs per tre a tm e n t) w ere constrained by the lim ited qu a n tity o f GTX I we w ere able to isolate fro m several kg o f dried R. ponticum flow ers, as per m ethods previously reported (Tiedeken et al. 2014). However, since there is typically low betw een-individual variation in BVWs due to obligate parthenogenesis (Stenberg and Lundmark 2004), we considered these sample sizes adequate. Experiments w ere conducted fo r a to ta l o f 11 days (w ith a single change o f cellulose disks at day 5.5) in conditions m aintained at ca. 21 °C and 85 % relative hum idity (Shanks and Finnigan 1973, Fisher and Bruck 2004). The cum ulative area eaten (mm^) fro m disks was quantified per weevil fro m digital scans using ImageJ analysis softw are (National Institutes o f Health, Bethesda, M aryland, USA). For both field and laboratory assessments, results are reported in term s of resistance (i.e. 1 m inus % herbivore damage). In addition to resistance, we also assessed tolerance to herbivory as a com plem entary defence strategy which is often co-em ployed by plants (Carmona and Fornoni 2013). In field studies, tolerance was quantified per range as the slope o f relative fitness regressed on percent herbivore damage (Wise and Carr 2008).
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Alarms are used in chemical processing plants to

Alarms are used in chemical processing plants to

Alarm management has become increasingly important as chemical plants look for ways to reduce costs, increase productivity, and deal with the loss of experienced operators. It has also become more chal- lenging due to the adoption of the modern distributed control system (DCS). Alarm systems of the past consisted of panel- board control rooms, where the number of alarms was limited by the finite wall space, and there was an actual cost to hard-wire the system into the process (approximately $1,000 per alarm) (1). Today, alarms are considered free because they are implemented via software. Consequently, less
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Some Aspects of Chemical Changes During Insect Metamorphosis

Some Aspects of Chemical Changes During Insect Metamorphosis

In order to study in more detail these interesting changes in fatty acid content, the iodine and thiocyanogen values of the fatty acids obtained from one detailed study were taken and th[r]

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Induced resistance in plants and counter-adaptation by insect pests

Induced resistance in plants and counter-adaptation by insect pests

insect pests. In Brassicaceae, glucosinolates and myrosinases are hydrolyzed to toxic isothiocyanates (mustard oils) and other biologically active products (64). Together the glucosinolates and myrosinases constitute an activated plant defense system known as the ‘‘mustard oil bomb’’. The abrupt release of these compounds produces toxicity in insect pests (64, 65). Glucosinolate–myrosinase system is as defensive in plants as commercial insecticides. High glucosinolate and myrosinase containing lines of Brassica juncea L. are more defensive against Spodoptera eridania (Cramer) larvae than the ones with less glucosinolate and myrosinase content (65). However, adaptation of the P. xylostella and many other insect pests to glucosinolate- myrosinase system has nullified the value of this system as a defensive strategy. The glucosinolates and the specific enzyme (myrosinase) are stored in separate compartments of the cells (idioblasts and guard cells), and are distributed in different parts of an organ unevenly (30). They are stored in special sulfur-rich cells called as S-cells situated close to the phloem (66). When the tissue is damaged, the glucosinolates and myrosinases come in contact with each other, and the glucosinolates are hydrolysed to highly toxic products, such as isothiocyanates. These isothiocyanates are the important plant defensive compounds, however, insect pests have developed adaptations to reduce and/or evade the toxicity of glucosinolates, and have even evolved strategies to sequester them and use them for their own defense. For example, P. xylostella modifies the glucosinolates by sulfatase gut enzyme avoiding their hydrolysis (12). Myzus persicae (Sulz.), Athalia rosae (L.) and Pieris
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The concept of vulnerability in security assessment of chemical plants

The concept of vulnerability in security assessment of chemical plants

Vulnerability can simply be represented by any weakness in an asset or facility’s design. Vulnerability assessment is based on the analysis of scenario or the vulnerability of every asset. Vulnerability assessment also includes the assessment of system’s effectiveness that concentrates on physical protection systems (prevention, detection, delay, response, resilience). Facilities such as vehicle barriers, fences, barbed wire, doors, windows, walls, terrain-following, locks and other physical protection systems are equipped primarily to prevent the occurrence of adversary’s attacks. If adversaries take action to attack assets of chemical plants, security forces must be able to detect an attack soon enough so as to react to adversaries. Continuous video monitoring of an area, fixed cameras, pan-tilt-zoom (PTZ) cameras, sensors, line detection, physical detection and CCTV all can be used in the process of detection. Also, a sufficiently potent response force to arrive and interrupt the attack is needed before the attack succeeds in stealing, releasing, destroying or otherwise compromising the facilities’ critical assets. Since the attacks really happen and give rise to consequences, emergency relief workers must react to the accidents as soon as possible. Public relations officials and media professionals need to take action according to the situation in case of false reports.
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Chemical studies on three plants of biological interest

Chemical studies on three plants of biological interest

Since a study of the chloroform extract of the plant had been carried out, the present work concentrated on the more polar fractions, that is, those present in the MeOH/H20 extract, sinc[r]

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Volatile chemical interaction between undamaged plants

Volatile chemical interaction between undamaged plants

The adaptive significance of these insect responses is still not apparent, however aphid natural enemies are known to be sensitive to the quality of their aphid hosts, and should forage optimally to locate and exploit the best quality hosts. Barley plants that became attractive to aphid natural enemies after volatile exposure also appear to be less preferred as hosts by aphids. However, experiments suggest that aphids developing on plants exposed to volatiles from a different cultivar represent higher quality hosts for aphid natural enemies. For example, ladybirds consumed more aphids that had developed on exposed plants than on unexposed plants, and female parasitoids attacked and laid more eggs in aphids that had developed on exposed plants (Glinwood et al. 2009 ). Parasitoid egg development did not appear to be affected, suggesting that natural enemies may have handled aphid prey items more efficiently, perhaps due to decreased defensive behaviour by the aphids.
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A Review on the Effect of Organic and Chemical Fertilizers on Plants

A Review on the Effect of Organic and Chemical Fertilizers on Plants

Organic farming is one of the fastest growing sectors of the agriculture worldwide and its main objective is to create a balance between the inter-connected system such as soil organism, plants, animals and humans (Berova, et al., 2010). The organic fertilizers offer the biological process necessities of plants and conjointly suppress the plant pests’ populations (Heeb et al., 2005a; Heeb et al., 2005b; Heeb et al., 2006; Liu et al., 2007; Tonfack et al., 2009). Additionally, they increase the microorganism activity in soil, anion and cation exchange capability, organic matter and carbon-content of soil. Organic fertilizers increase the quality and yield of agricultural crops in ways similar to inorganic fertilizers (Bulluck and Ristaino, 2002; Bulluck et al., 2002; Arancon et al., 2004), however it does not cause environment pollution. Some of the important advantages of organic fertilizers include improved soil texture, water retention and resistance to erosion. Organic fertilizers provide nitrogen in a usable form, which will help plant to improve plant growth while at the same time neither cause burning of roots nor destroying beneficial micro-organisms in the soil. Organic fertilizers help to prevent diseases by meeting the plants ‘nutritional needs and enhancing plant tolerance. This action removes a serious source of stress. Plant wastes such as wood ash, spent grain, rice bran, and sawdust were effective as fertilizers (Ogbalu, 1999). According to Ogbalu (1999) ancient sources of nutrients are accessible to farmers and therefore the use of chemical fertilizers by villagers isn't common.
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Ecology of Upland Rice Plants and Seeds Subjected to Growth Regulator

Ecology of Upland Rice Plants and Seeds Subjected to Growth Regulator

tendency, with a high coefficient of determination (R = 0.99), as can be observed in Figure 1. During the initial period of the crop cycle of plants in all treatments, a phase of slow growth occurred until 42 DAE, following a phase of intense growth. From 56 DAE, it is possible to observe a reduction in the growth of plants subjected to the growth regulator. At 98 DAE, there was an intense reduc- tion in dry matter allocation in plants subjected to growth regulator, with a re- duction of approximately 25%, 40% and 41% in plants subjected to the doses 0.25, 0.50 and 0.75 L·ha −1 , respectively, compared to plants without growth reg-
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Behavioural Ecology of Insect Parasitoids - from theoretical approaches to field applications (BEPAR)

Behavioural Ecology of Insect Parasitoids - from theoretical approaches to field applications (BEPAR)

Until the 1990s, behavioural ecologists largely focussed on developing and testing theoretical predic- tions for the fitness consequences of behaviour but devoted less effort to studying the behavioural rules (so-called proximate mechanisms) employed by the animals. In the last decade, behavioural ecologists have been trying to integrate the study of behavioural mechanisms with the functional approach of studying the fitness consequences of behaviour. A wealth of knowledge is available on the behavioural mecha- nisms employed by parasitoids to find hosts and allo- cate offspring to them, but how these mechanisms contribute to fitness or act as constraints on the opti- mization of reproductive behaviour of parasitoids is often poorly known. One main aim of the programme is thus to foster the development of theory in behav- ioural ecology that incorporates knowledge of the underlying mechanisms of parasitoid behaviour in models that predict maximal fitness. The results obtained that way can be used to define more efficient biological control technologies of insect pests in agri- culture.
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