The Variation of Selected Physiological Parameters in Elm Leaves (Ulmus glabra Huds.) Infested by Gall Inducing Aphids.

Three aphid species, Eriosoma ulmi (L.), Colopha compressa (Koch) and Tetraneura ulmi (L.) induce distinct gall morphotypes on Ulmus glabra Huds.; opened and closed galls. Because the trophic relationship of aphids and their galls shows that throughout the gall formation aphids can elicit multiple physiological regulations, we evaluated the changes of hydrogen peroxide content (H2O2), cytoplasmic membrane condition, expressed as electrolyte leakage (EL) and concentration of thiobarbituric acid reactive substances (TBARS), as well as, the activity of catalase (CAT), guaiacol peroxidase (GPX) and ascorbate peroxidase (APX) in gall tissues, as well as, in damaged and undamaged parts of galled leaves. All aphid species increased EL from gall tissues and significantly upregulated APX activity in galls and galled leaves. Alterations in H2O2 and TBARS concentrations, as well as GPX and CAT activities, were aphid- and tissue-dependent. The development of pseudo- and closed galls on elm leaves did not have a clear effect on the direction and intensity of the host plant's physiological response. The different modes of changes in H2O2, TBARS, CAT and GPX were found in true galls of C. compressa and T. ulmi. Generally, physiological alterations in new plant tissues were quite different compared to other tissues and could be considered beneficial to galling aphids.

The effect of Tanacetum vulgare essential oil and its main components on some ecological and physiological parameters of Acrobasis advenella (Zinck.) (Lepidoptera: Pyralidae).

Acrobasis advenella (Zinck.) is the most dangerous pest of black chokeberry (Aronia melanocarpa [Michx.] Elliot). The aim of this study was to investigate the insecticidal activity of an essential oil from Tanacetum vulgare (L.) and its main components such as thujone, camphor, and borneol against A.advenella larvae. In addition, the effects of the oil and its main ingredients on the activity of catalase (CAT), polyphenol oxidase (PPO), peroxidase (POX), and α- and ß-glucosidases, which are important antioxidants, detoxification enzymes, and digestive enzymes, were examined. Our study showed an increased mortality of larvae and a decrease in the percentage of pupation and emergence of A. advenella moths as well as their longevity. Moreover, we found a significant increase in catalase and polyphenol oxidase activity in larvae feeding on inflorescences treated with T. vulgare EO. The results showed a significant increase in peroxidase assay activity in insects feeding on plants treated with borneol and thujone. However, a significant decrease in peroxidase activity was noted after the use of T. vulgare essential oil. It was shown that the activity of α- and ß-glucosidase significantly decreased in larvae fed on inflorescences treated with the essential oil and all substances but the greatest decrease in the activity of α- and ß-glucosidase was shown in larvae after thujone treatment. The results suggest that T. vulgare essential oil and its compounds can be useful in protecting organic crops of black chokeberry.

The insecticidal activity of Satureja hortensis essential oil and its active ingredient -carvacrol against Acrobasis advenella (Zinck.) (Lepidoptera, Pyralidae).

Nowadays, Acrobasis advenella is considered a pest of the highest economic significance in black chokeberry plantations, negatively affecting the quantity and quality of fruits. The aim of this study was to investigate the effect of Satureja hortensis essential oil and its main constituent, carvacrol, on the life cycle and physiology of A. advenella. The metabolic activity of both preparations was evaluated against insect α- and ß- glucosidase, catalase, peroxidase and polyphenol oxidase. The results showed S. hortensis essential oil and carvacrol, are characterized by insecticidal activity against A. advenella larvae. It found an increase in catalase activity in A. advenella homogenates under the influence of carvacrol and an induction of polyphenol oxidase by S. hortensis EO with no changes in POX activity. Also, it was shown that the activity of α- and ß-glucosidase significantly increased in larvae fed on inflorescences treated with the essential oil and carvacrol. These preparations particularly strongly affected ß-glucosidase activity in the insect homogenates. S. hortensis essential oil reduced emergence the longevity of moths. The obtained results suggest that S. hortensis essential oil and carvacrol can be useful in protecting organic crops of black chokeberry but essential oils may be more effective biopesticides than their active ingredients separately.

Physiological Response of Basil Plants to Twospotted Spider Mite (Acari: Tetranychidae) Infestation.

The induction of plant resistance against pests is considered a potential method of controlling mite infestation as it restricts the use of chemical pesticides in herbal crops. Our goal was to investigate whether plant physiological response to mite feeding varied depending on basil cultivar and/or duration of mite infestation. The effect of plant acceptance, mite mortality rate, and changes in physiological parameters: malondialdehyde content (MDA), hydrogen peroxide (H2O2) concentration, and antioxidant enzyme activities, including guaiacol peroxidase (GPX) and catalase (CAT) were examined in this study. Tetranychus urticae Koch (Acari: Tetranychidae) infestation induced oxidative stress in three Ocimum basilicum L. cultivars: 'Sweet basil,' 'Purpurascens,' and 'Fino Verde.' The analysis of mite behavior and alteration in metabolic plant profiles showed different sensitivities of basil cultivars to biotic stress that were dependent on the cultivar and duration of infestation. All basil plants were suitable as host plants for T. urticae, but they varied in the level of susceptibility to mite feeding. O. basilicum 'Fino Verde' was the most suitable host for the twospotted spider mite. In turn, O. basilicum 'Purpurascens' was characterized by the lowest level of susceptibility to T. urticae feeding. The lowest acceptance, the highest mortality of twospotted spider mite individuals as well as decreased levels of H2O2 and MDA, significantly increased GPX activity and low level of CAT activity were recorded in O. basilicum 'Purpurascens' leaves. Research on plant responses to biotic stress can inform breeding cultivars resistant to arthropod attack.

Parasitoid complex associated with the overwintering generation of Swammerdamia pyrella (Lepidoptera: Yponomeutidae) in Poland.

The study was conducted on fruit trees where bands of corrugated cardboard were attached around the trunks of the trees, which were used to catch the larvae of overwintering generation of the rufous-tipped swammerdamia moth, Swammerdamia pyrella (Villers) (Lepidoptera: Yponomeutidae). Twenty-five species of parasitic Hymenoptera have been described from S. pyrella in Poland including the report in this article of seven species belonging to the family of Ichneumonidae (three species) and superfamily Chalcidoidea (four species). The parasitoids Gelis agilis F. (Ichneumonidae), Chrysocharis aquilegiae (Erdös) (Eulophidae), Catolaccus ater (Ratzeburg) (Pteromalidae), and Eupelmus urozonus (Dalman) (Eupelmidae) had not been reported from the host before. Triclistus pallipes Holmgren (Ichneumonidae), Dibrachys cavus Walker (Pteromalidae) had the greatest effect on the natural regulation of S. pyrella population. Parasitization for the wintering cocoons of S. pyrella changed each year, but it was high throughout the study. The contribution of secondary parasitoids was much higher than primary parasitoids.