Effects of Larch Woolly Adelgid Infestation on Morphological, Histological and Allelochemical Traits of European Larch Needles.

The study was carried out to assess the effect of the larch wooly adelgid Vallot (Hemiptera: Adelgidae) infestation on its secondary host, the European larch Mill. Morphology and anatomy of adelgid-infested needles, and content of defense phenolic compounds including individual flavonoids isorhamnetin, kaempferol, quercetin, rutin, catechin, epicatechin, apigenin, ampelopsin and taxifolin, were analyzed. The amount of total phenols in needles from adelgid-infested twigs of increased following the development of the population, from the end of April until the end of June.

Genistein and Aphid Probing Behavior: Case Studies on Polyphagous Aphid Species.

(1) Background: Genistein is a naturally occurring flavonoid with a rich spectrum of biological activities, including plant-herbivore interactions. The aim of the study was to evaluate the effect of exogenous application of genistein on aphid behavior during probing in plant tissues. (2) Methods: , ssp.

Hesperidin as a Species-Specific Modifier of Aphid Behavior.

Hesperidin is a highly bioactive natural flavonoid whose role in ecological interactions is poorly known. In particular, the effects of hesperidin on herbivores are rarely reported. Flavonoids have been considered as prospective biopesticides; therefore, the aim of the present study was to examine the influence of hesperidin on the host plant selection behavior of three aphid (Hemiptera: Aphididae) species: Harrris, (L.

Antifeedant Potential of Geranylacetone and Nerylacetone and Their Epoxy-Derivatives against (Sulz.).

Geranylacetone and nerylacetone are natural sesquiterpenoids, which play various roles in plant-insect interactions, including the deterrent and repellent effects on herbivores. The structural modifications of natural compounds often change their biological activities. The aim of the study was to evaluate the effect of geranylacetone, nerylacetone and their epoxy-derivatives on the probing and settling behavior of (Sulz.

Effect of Soy Leaf Flavonoids on Pea Aphid Probing Behavior.

Flavonoids detected in soybean (L.) Merr. (Fabaceae) cause various alterations in the metabolism, behavior, and development of insect herbivores.

Antixenosis in Glycine max (L.) Merr against Acyrthosiphon pisum (Harris).

To reveal the antixenosis potential against the pea aphid Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae) we analyzed the pea aphid survival and probing behavior, and the quantitative and qualitative variation of flavonoids in the leaves of selected soybean Glycine max (L.) Merr (Fabaceae) cultivars 'Aldana', 'Annushka', 'Augusta', 'Madlen', 'Mavka', 'Simona', 'Violetta', and 'Viorica'. Aphid survival was drastically impeded on all cultivars.

Quercetin and Rutin as Modifiers of Aphid Probing Behavior.

Rutin and its aglycone quercetin occur in the fruits, leaves, seeds, and grains of many plant species and are involved in plant herbivore interactions. We studied the effect of the exogenous application of rutin and quercetin on the probing behavior (= stylet penetration activities in plant tissues) of on on ssp. , and on using the electrical penetration graph technique (EPG = electropenetrography).

Probing behavior of Adelges laricis Vallot (Hemiptera: Adelgidae) on Larix decidua Mill: Description and analysis of EPG waveforms.

Adelgidae are a sister group of Aphididae and Phylloxeridae within Hemiptera, Aphidoidea and occur exclusively on Pinaceae. The piercing-sucking mouthparts of Adelgidae are similar to those of aphids and it is believed that adelgids ingest sap from both the non-vascular and vascular (phloem) tissues. The aim of the present study was to identify and characterize the adelgid stylet activities during their penetration in plant tissues.

Synthesis of novel phytol-derived γ-butyrolactones and evaluation of their biological activity.

The synthesis of phytol-derived γ-butyrolactones as well as their evaluation for deterrent activity towards peach-potato aphid Myzus persicae and antiproliferative activity against four selected cancer cell lines are reported. Products were obtained in good yields (19-96%) and their structures were fully characterized by spectroscopic data (NMR, HRMS). Four synthesized δ-halo-γ-lactones (4-7) are new and have not been previously described in the literature.

Repellent and Antifeedant Activities of Citral-Derived Lactones against the Peach Potato Aphid.

Citral is well known for its antimicrobial, antifungal, and insecticidal activities. Natural sesquiterpene α-methylenelactones also exhibit a broad spectrum of biological activities. The aim of the study was to explore the effect of structural changes to citral molecules on citral behavior-modifying activity towards .

Effect of Naringenin and Its Derivatives on the Probing Behavior of (Sulz.).

Substances that alter insect behavior have attracted a lot of attention as potential crop protection agents. Naringenin (5,7,4'-trihydroxyflavanone) is a naturally occurring bioactive flavanone. We evaluated the influence of naringenin on aphid activities during individual phases of probing and feeding and the effect of structural modifications of naringenin on its activity towards aphids.

Behavioral and physiological effects of Viola spp. cyclotides on Myzus persicae (Sulz.).

Cyclotides are defense peptides produced by several plant families. Viola spp. (Violaceae) produce an array of cyclotides with varying biological activities.

New insight into the behaviour modifying activity of two natural sesquiterpenoids farnesol and nerolidol towards (Sulzer) (Homoptera: Aphididae).

The effect of structurally related sesquiterpenoids (E,E)-farnesol and cis-nerolidol on the host-plant selection behaviour of the peach potato aphid Myzus persicae (Sulz.) was evaluated using electrical penetration graph (EPG) technique. No repellent effects of (E,E)-farnesol and (Z)-nerolidol to M.

Oxidative stress links response to lead and Acyrthosiphon pisum in Pisum sativum L.

This study demonstrates the impact of lead at hormetic (0.075 mM Pb(NO)) and sublethal (0.5 mM Pb(NO)) doses on the intensity of oxidative stress in pea seedlings (Pisum sativum L.

β-Thujone and Its Derivatives Modify the Probing Behavior of the Peach Potato Aphid.

Thujone is a natural biologically active monoterpene ketone component of essential oils of numerous plants. The aim of the study was to evaluate the effect of β-thujone and β-thujone derivatives bisulfite adduct, lactone, oxime, and lactam application on behavior of (Sulz.) (Hemiptera: Aphididae) during probing and settling.

Synthesis and Biological Activity of New 4-tert-Butylcyclohexanone Derivatives.

In the synthesis performed in this study, derivatives of 4-tert-butylcyclohexanone 1 were obtained using typical reactions of organic synthesis. The bioactivity of the selected compounds was evaluated. 1-(Bromomethyl)-8-tert-butyl-2-oxaspiro[4.

Synthesis and biological activity of new derivatives with the preserved carane system.

Terpenoid derivatives, which contain a preserved carane system in their structure, exhibit a broad spectrum of biological activities. Among them, we can distinguish insecticides, structures with pharmacological application etc. In the presented paper, the substrate - (-)-cis-caran-trans-4-ol was transformed using the reactions of typical organic synthesis to obtain novel derivatives.

Antixenosis Potential in Pulses Against the Pea Aphid (Hemiptera: Aphididae).

The aim of the study was to explore the acceptability of 14 species, varieties, and cultivars of grain legumes (Fabales: Fabaceae) to the pea aphid, by investigating the aphid probing behavior using the electrical penetration graph (EPG) technique. Phaseolus coccineus L. 'Felicia', Pisum sativum L.

Novel Hydroxy- and Epoxy--Jasmone and Dihydrojasmone Derivatives Affect the Foraging Activity of the Peach Potato Aphid (Sulzer) (Homoptera: Aphididae).

Jasmonates show great potential in sustainable agriculture due to their various roles in natural mechanisms of plant defense, and because they are non-toxic, non-mutagenic, and easily metabolized. The aim of the study was to explore structure⁻activity relationships of dihydrojasmone, -jasmone, and their derivatives at the plant⁻aphid interface. We focused on the behavioral responses of aphids, following the exogenous application of natural jasmonates and their derivatives to the host plants.

The Dynamics of the Defense Strategy of Pea Induced by Exogenous Nitric Oxide in Response to Aphid Infestation.

The aim of this study was to investigate the effect of exogenous nitric oxide (NO), i.e., -nitrosoglutathione (GSNO) and sodium nitroprusside (SNP), on the metabolic status of L.

Biotransformation of Bicyclic Halolactones with a Methyl Group in the Cyclohexane Ring into Hydroxylactones and Their Biological Activity.

The aim of this study was the chemical synthesis of a series of halo- and unsaturated lactones, as well as their microbial transformation products. Finally some of their biological activities were assessed. Three bicyclic halolactones with a methyl group in the cyclohexane ring were obtained from the corresponding γ,δ-unsaturated ester during a two-step synthesis.

Alkyl-Substituted δ-Lactones Derived from Dihydrojasmone and Their Stereoselective Fungi-Mediated Conversion: Production of New Antifeedant Agents.

A chemoenzymatic method was applied to obtain optically pure alkyl-substituted δ-lactones. First, chemical Baeyer-Villiger oxidation of dihydrojasmone (1) was carried out, affording two new alkyl-substituted δ-lactones: 3,4-dihydro-5-methyl-6-pentyl-2H-pyran-2-one (2) and 5-methyl-6-pentyl-1,13-dioxabicyclo[4.1.

Chemo-Enzymatic Synthesis of Optically Active γ- and δ-Decalactones and Their Effect on Aphid Probing, Feeding and Settling Behavior.

The enantiomerically enriched γ- and δ-decalactones (4a and 4b) were prepared from corresponding racemic primary-secondary 1,4- and 1,5-diols (1a and 1b), as products of enzymatic oxidation catalyzed by different alcohol dehydrogenases. The results of biotransformations indicated that the oxidation processes catalyzed by alcohol dehydrogenase (HLADH), both isolated from horse liver and recombinant in Escherichia coli, were characterized by the highest degree of conversion with moderate enantioselectivity of the reaction. Useful, environmentally friendly extraction procedure of decalactones (4a and 4b) based on hydrodistillation using a Deryng apparatus was developed.

Systemic deterrence of aphid probing and feeding by novel -damascone analogues.

-Damascone appeared a weak attractant close to not active to , but modifications of its structure caused the avoidance of treated leaves by aphids during settling and reluctance to probe in simple choice- and no-choice experiments in previous studies. Here, the electrical penetration graph (EPG) technique, which allows monitoring of aphid probing within plant tissues, was applied to explore the biological background and localisation in plant tissues of the deterrent activities of -damascone and its analogues. Activity of -damascone and -damascone-derived compounds depended on their substituents, which was manifested in the variation in the potency of the behavioural effect and differences in aphid probing phases that were affected.

Insect Antifeedant Potential of Xanthohumol, Isoxanthohumol, and Their Derivatives.

Xanthohumol (14) and isoxanthohumol (6) derived from hop (Humulus lupulus L., Cannabaceae) and selected chalcone and chromene derivatives, obtained by chemical synthesis, were studied for antifeedant activity against the peach-potato aphid (Myzus persicae [Sulz.]).