Chrysolina herbacea Modulates Terpenoid Biosynthesis of Mentha aquatica L.

Interactions between herbivorous insects and plants storing terpenoids are poorly understood. This study describes the ability of Chrysolina herbacea to use volatiles emitted by undamaged Mentha aquatica plants as attractants and the plant's response to herbivory, which involves the production of deterrent molecules. Emitted plant volatiles were analyzed by GC-MS. The insect's response to plant volatiles was tested by Y-tube olfactometer bioassays. Total RNA was extracted from control plants, mechanically damaged leaves, and leaves damaged by herbivores. The terpenoid quantitative gene expressions (qPCR) were then assayed. Upon herbivory, M. aquatica synthesizes and emits (+)-menthofuran, which acts as a deterrent to C. herbacea. Herbivory was found to up-regulate the expression of genes involved in terpenoid biosynthesis. The increased emission of (+)-menthofuran was correlated with the upregulation of (+)-menthofuran synthase

Effect of extracts of garlic [Allium sativum L.], wormwood [Artemisia absinthium L.] and tansy [Tanaceum vulgare L.] on the behaviour of the peach potato aphid Myzus persicae [Sulz.] during the settling on plants

Plant derived extracts and phytochemicals have long been a subject of research in an effort to develop alternatives to conventional insecticides but with reduced health and environmental impact. In the present study, the aphid settling deterrent activity of extracts obtained from garlic (Allium sativum L.), wormwood (Artemisia absinthium L.) and tansy (Tanaceum vulgare L.) against peach potato aphid (Myzus persicae [Sulz.]) was investigated. The settling of M. persicae on host plant leaves was strongly deterred by soap 1%, soap 4%, Bioczos Forte 2% + soap 1%, Bioczos 1% + tansy extract 1%. Their effect was observed after 1 hour aphid had got access to the plants and it lasted until the end of the experiment, i.e. 24 hours after application. After 24 hours, aphid settling was deterred by the following combinations of extracts: Bioczos 2%, Bioczos 2% + soap 1%, Bioczos 5%, Bioczos 5% + soap 1%, Bioczos 1% + wormwood extract 1%, Bioczos 1% + wormwood extract 1% + soap, tansy extract 1% + wormwood extract 1% and tansy extract 1% + wormwood extract 1% + soap 1%

Effect of farnesol and its synthetic derivatives on the settling behaviour of the peach potato aphid Myzus persicae (Sulz.)

The behavioural effect of trans,trans-farnesol and its structural derivatives on M. persicae was evaluated. The incorporation of carboxy group into the molecule did not alter the strong deterrent activity of farnesol. The lactonization and the epoxidation of farnesol caused the delay in expression and the loss of deterrent activity, respectively. The ester, product of Claissen rearrangement of farnesol and iodolactone did not exhibit significant biological effect

W poszukiwaniu biopestycydów: wpływ olejku eterycznego z kminku Carum carvi i jego głównych składników na zachowanie mszycy brzoskwiniowej Myzus persicae podczas penetracji roślin

The application of caraway essential oil and its main components, carvone and limonene, to plant surface caused significant changes in aphid probing at the level of non-vascular tissues as well as sieve elements. On treated plants, probes were short and non-probing intervals were long, phloem phase was short and sustained sap ingestion periods occurred sporadically. The deterrent activity of caraway oil is determined mainly by the content of carvone that has the most significant impact on aphid probing behavior. The impediment of aphid probing at the pre-ingestive (pre-phloem) and/or ingestive (phloem) phases revealed the passage of compounds through the plant surface and distribution within tissues in a systemic way