Electrophysiological and behavioral responses of female African rice gall midge, Orseolia oryzivora Harris and Gagné, to host plant volatiles.

African rice gall midge, Orseolia oryzivora Harris and Gagné, is a major pest of rice in Africa. Depsite its economic importance, its chemical ecology is not well understood. Here, we assessed behavioral and electrophysiological responses of O.

A comparison of the levels of hydroxamic acids in Aegilops speltoides and a hexaploid wheat and effects on Rhopalosiphum padi behaviour and fecundity.

Hydroxamic acids (HAs) are plant secondary metabolites produced by certain cereals, which have been found to be toxic to pest aphids in artificial diet assays. Previous studies have shown that tetraploid and hexaploid wheat varieties, the leaf tissues of which contained higher levels of these compounds than used in artificial diets, did not reduce aphid settling or fecundity. This current study reports findings on a high HA producing B genome accession of the diploid ancestor of wheat, Aegilops speltoides.

Responses of herbivore and predatory mites to tomato plants exposed to jasmonic acid seed treatment.

Jasmonic acid (JA) signalling can influence plant defense and the production of plant volatiles that mediate interactions with insects. Here, we tested whether a JA seed treatment could alter direct and indirect defenses. First, oviposition levels of herbivorous mites, Tetranychus urticae, on JA seed-treated and control tomato plants were compared.

Activation of defence in sweet pepper, Capsicum annum, by cis-jasmone, and its impact on aphid and aphid parasitoid behaviour.

Background: Two important pests of the sweet pepper, Capsicum annuum, are the peach potato aphid, Myzus persicae, and the glasshouse potato aphid, Aulacorthum solani. Current aphid control measures include the use of biological control agents, i.e.

Benzoxazinoid metabolites regulate innate immunity against aphids and fungi in maize.

Benzoxazinoids (BXs), such as 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA), are secondary metabolites in grasses. The first step in BX biosynthesis converts indole-3-glycerol phosphate into indole. In maize (Zea mays), this reaction is catalyzed by either BENZOXAZINELESS1 (BX1) or INDOLE GLYCEROL PHOSPHATE LYASE (IGL).

Development of semiochemical attractants for monitoring bean seed beetle, Bruchus rufimanus.

Background: Bruchus rufimanus is a serious pest of field beans. The objective here was to develop a semiochemical-baited trapping system to facilitate monitoring of the pest.

Results: Volatile compounds that were electrophysiologically active with the antennae of B.

Phytochemicals of Brassicaceae in plant protection and human health--influences of climate, environment and agronomic practice.

In this review, we provide an overview of the role of glucosinolates and other phytochemical compounds present in the Brassicaceae in relation to plant protection and human health. Current knowledge of the factors that influence phytochemical content and profile in the Brassicaceae is also summarized and multi-factorial approaches are briefly discussed. Variation in agronomic conditions (plant species, cultivar, developmental stage, plant organ, plant competition, fertilization, pH), season, climatic factors, water availability, light (intensity, quality, duration) and CO(2) are known to significantly affect content and profile of phytochemicals.

Aphid resistance in wheat varieties.

As an environmentally compatible alternative to the use of conventional insecticides to control cereal aphids, we have investigated the possibility to exploit natural resistance to insect pests in wheat varieties. We have tested a wide range of hexaploid (Triticum aestivum), tetraploid (T. durum) and diploid (T.

To alloy or not to alloy? Cr modified Pt/C cathode catalysts for PEM fuel cells.

The cathode electrocatalysts for proton exchange membrane (PEM) fuel cells are commonly platinum and platinum based alloy nanoparticles dispersed on a carbon support. Control over the particle size and composition has, historically, been attained empirically, making systematic studies of the effects of various structural parameters difficult. The controlled surface modification methodology used in this work has enabled the controlled modification of carbon supported Pt nanoparticles by Cr so as to yield nanoalloy particles with defined compositions.

cis-Jasmone induces Arabidopsis genes that affect the chemical ecology of multitrophic interactions with aphids and their parasitoids.

It is of adaptive value for a plant to prepare its defenses when a threat is detected, and certain plant volatiles associated with insect damage, such as cis-jasmone (CJ), are known to switch-on defense metabolism. We used aphid and aphid parasitoid responses to Arabidopsis thaliana as a model system for studying gene expression and defense chemistry and its impact at different trophic levels. Differential responses to volatiles of induced Arabidopsis occurred for specialist and generalist insects: the generalist aphid, Myzus persicae, was repelled, whereas the specialist, Lipaphis erysimi, was attracted; the generalist aphid parasitoid Aphidius ervi was attracted, but the specialist parasitoid Diaeretiella rapae was not affected.

Developments in aspects of ecological phytochemistry: the role of cis-jasmone in inducible defence systems in plants.

The challenges and opportunities for protecting agricultural production of food and other materials will be met through exploiting the induction of defence pathways in plants to control pests, diseases and weeds. These approaches will involve processes that can be activated by application of natural products, patented in terms of this use, to "switch on" defence pathways. Already, a number of secondary metabolite defence compounds are known for which the pathways are conveniently clustered genomically, e.

cis-Jasmone induces accumulation of defence compounds in wheat, Triticum aestivum.

Liquid phase extraction (LPE) and vapor phase extraction (VPE) methodologies were used to evaluate the impact of the plant activator, cis-jasmone, on the secondary metabolism of wheat, Triticum aestivum, var. Solstice. LPE allowed the measurement of benzoxazinoids, i.

Development of a pheromone trap monitoring system for orange wheat blossom midge, Sitodiplosis mosellana, in the UK.

Field-trapping experiments with synthetic 2,7-nonadiyl dibutyrate, the female-produced sex pheromone of the orange wheat blossom midge, Sitodiplosis mosellana (Géhin), demonstrated that pheromone traps were highly attractive to males and caught very few non-target organisms. Different formulations of pheromone were tested to identify the optimum release rate and dispenser type for use in pheromone traps in the UK. Key findings were that racemic pheromone was as effective as enantiomerically pure (2S,7R)-2,7-nonadiyl dibutyrate, that release rates higher than 0.

Aphid alarm pheromone produced by transgenic plants affects aphid and parasitoid behavior.

The alarm pheromone for many species of aphids, which causes dispersion in response to attack by predators or parasitoids, consists of the sesquiterpene (E)-beta-farnesene (Ebetaf). We used high levels of expression in Arabidopsis thaliana plants of an Ebetaf synthase gene cloned from Mentha x piperita to cause emission of pure Ebetaf. These plants elicited potent effects on behavior of the aphid Myzus persicae (alarm and repellent responses) and its parasitoid Diaeretiella rapae (an arrestant response).

Response of economically important aphids to components of Hemizygia petiolata essential oil.

The essential oil of Hemizygia petiolata Ashby (Lamiaceae) contains high levels (>70%) of the sesquiterpene (E)-beta-farnesene, the alarm pheromone for many economically important aphid species. In order to test the suitability of H. petiolata oil as a source of (E)-beta-farnesene for use in new integrated aphid control strategies, behavioural responses of pest aphid species were studied in laboratory and field experiments.

Responses of female orange wheat Blossom midge, Sitodiplosis mosellana, to wheat panicle volatiles.

Air entrainment samples of volatiles from panicles of intact wheat, Triticum aestivum, cultivar 'Lynx' were collected at the ear emergence/early anthesis growth stage. In an olfactometer bioassay, both freshly cut panicles and an air entrainment sample were found to attract female orange wheat blossom midge adults, Sitodiplosis mosellana. Coupled gas chromatography-electroantennography (GC-EAG) analyses of panicle volatiles located six electrophysiologically active components.

Orientation and feeding responses of the pollen beetle, Meligethes aeneus, to candytuft, Iberis amara.

The pollen beetle, Meligethes aeneus, which is an important pest of oilseed rape, Brassica napus, and turnip rape, B. rapa var. campestris, does not oviposit in all species of the Brassicaceae.

cis-Jasmone treatment induces resistance in wheat plants against the grain aphid, Sitobion avenae (Fabricius) (Homoptera: Aphididae).

cis-Jasmone is a plant volatile known to have roles as an insect semiochemical and in inducing plant defence. It was evaluated in laboratory and field trials for control of cereal aphids. In an olfactometer bioassay cis-jasmone was repellent to alatae of the grain aphid, Sitobion avenae (Fabricius) (Homoptera: Aphididae).

Synthesis of chromium-containing pigments from chromium recovered from leather waste.

Cobalt-chromite green and chrome-tin pink pigments have been prepared from chromium extracted from leather shavings produced as a waste product of the leather-tanning industry. The alkaline agent (NaOH, CaO, MgO, NH4OH) used in the extraction process influences the nature of the final product. The effect of the NH4OH:CaO ratio on the final product in the case of cobalt-chromite green was examined.