The causal agent of tan spot of wheat, Pyrenophora tritici-repentis is largely understudied in terms of the producing of potentially toxic secondary metabolites. The main goal of this study was to analyze main metabolites in cultures of P. tritici-repentis Vol2 obtained on different substrates and compare their toxicity. Four tetramic acid derivatives (triticones A/B, C, and D, and curvupallide C) were isolated from the culture filtrate obtained on M1D liquid medium. Two anthraquinone pigments (catenarin and chrysophanol) and a macrolactone (10,11-dehydrocurvularin) were purified from the extract of millet solid culture. 10,11-Dehydrocurvularin (DHC) and triticones A/B (TAB) showed phytotoxic properties, antimicrobial activity, and strong toxicity toward Sf9 insect cells. Moreover, TAB were acute toxic to Galleria mellonella larvae in an injection assay, while DHC considerably inhibited spider mite reproductivity. TAB were the major metabolites in the extracts from culture filtrates of P. tritici-repentis in media containing ammonium tartrate as a nitrogen source. DHC was found to be a major metabolite of P. tritici-repentis on grain solid substrates with a yield from 2 to 110 mg/kg on pearl barley depending on strain. Thus, TAB and DHC can represent a potential threat for human and animals as mycotoxins of P. tritici-repentis, and therefore, their possible production in wheat grain should be further monitored.

Data on virulence of various species of entomopathogenic fungi of the genus Lecanicillium against the thrips Frankliniella occidentalis and the effect of the fungal spores and mycelium on the behavioral responses of the phytophage are presented. A pronounced repellent effect was found for 7 strains: Vl 21 (Lecanicillium muscarium), Vit 117 and Vit 71 (L. attenuatum), 2332 (L. dimorphum), 8057 and F 2 (L. lecanii), and Vl 13 (L. longisporum); the remaining strains showed a response with a tendency towards repellency. Most of the studied strains showed high virulence when the plants were treated with fungal conidia at a concentration of 1 × 10 mln spores/mL, causing 80–100

Fungal 10-membered lactones (TMLs), such as stagonolide A, herbarumin I, pinolidoxin, and putaminoxin, are promising candidates for the development of nature-derived herbicides. The aim of this study was to analyze the structure-activity relationships (SAR) of C-9-methyl-substituted TMLs with a multitarget bioassay approach to reveal compounds with useful (phytotoxic, entomotoxic, antimicrobial) or undesirable (cytotoxic) bioactivities. A new TML, stagonolide L (1), along with five known compounds (stagonolides D (2) and E (3), curvulides A (4) and B1/B2 (5a,b), and pyrenolide C (6)), were purified from cultures of the phytopathogenic fungus Stagonospora cirsii, and five semisynthetic derivatives of 3 and 4 (7-11) were obtained. The absolute configuration of 4 was revised to 2Z, 4S, 5S, 6R, and 9R. The identity of 5a,b and stagonolide H is discussed. The phytotoxicity of compound 4, the entomotoxicity of 5a,b, and nonselective toxicity of compound 6 are demonstrated. The latter confirms the hypothesis that the alpha,beta-unsaturated carbonyl group is associated with the high general toxicity of TML, regardless of its position in the ring and other substituents. The epoxide in compound 4 is important for phytotoxicity. The revealed SAR patterns will be useful for further rational design of TML-based herbicides including curvulide A analogs with a 4,5-epoxy group.

Previously, using an MS7-200 quadrupole mass spectrometer developed by the Institute for Analytical Instrumentation, sulfur dioxide was detected in volatile organic compounds (VOCs) released into the air by entomopathogenic fungi (EPF) of the genus Lecanicillium. In this work, we assessed the effect of this compound on such dangerous phytophages as the western flower thrips Frankliniella occidentalis and the green peach aphid Myzus persicae at low doses corresponding to the sulfur dioxide content of VOCs above the growing fungal mycelium. It was found that sulfur dioxide did not have a negative effect on females of the F. occidentalis thrips and their fertility when sulfur dioxide was introduced into vials at a concentration of 9 and 17 ppm and kept for 2 h. At a dose of 33 ppm, sulfur dioxide caused a 10

The wide range of biological activity of essential oils in relation to pests gives reason to consider them as additional plant protection products and in other measures aimed at reducing the number of harmful arthropods. This paper presents the results of a study of the biological activity of a mixture of thymol and carvacrol, which are part of the essential oils of many plants, including oregano Origanum vulgare L. for the peach aphid Myzus persicae. The use of essential oil and a mixture of its components as fumigants has demonstrated their high aphidocidal potential. When processing the leaves of a forage plant (beans), the ability of a mixture of thymol and carvacrol to reduce the viability of female aphids and the number of offspring was established, and on vegetative plants (pepper) to negatively affect the survival of individuals of the daughter generation in the preimaginal period. The short duration of action allows the use of oils and individual components in conjunction with biological control agents and pollinators, and assumes a slight or complete absence of residues in food products. Preparations based on essential oils of plants can be used immediately before harvesting, due to the minimum waiting period.

Earlier, using the MS7-200 quadrupole mass spectrometer developed by the IAP RAS, sulfur dioxide was detected as part of volatile organic compounds (VoCs) released into the air by entomopathogenic fungi (EPF) of the genus Lecanicillium. In this work, we evaluated the effect of this compound on such dangerous phytophages as the Western flower thrips Frankliniella occidentalis and the peach aphid Myzus persicae in low doses corresponding to the content of sulfur dioxide in the composition of VOCs over the growing mycelium of fungi. It was found that sulfur dioxide did not have a negative effect on female thrips F. occidentalis and their fertility when sulfur dioxide is injected into vials at concentrations of 9 and 17 ppm and kept for 2 hours. At a dose of 33 ppm, sulfur dioxide caused a 10% mortality of female thrips after 2 hours and 15.4% after 1 day, while a 36% decrease in female fertility was observed. Sulfur dioxide at concentrations of 17-33 ppm was nontoxic for peach aphid females after 2 hours. Aphid mortality at the level of 26% was noted after 2 days at a sulfur dioxide concentration of 33 ppm, while fertility decreased by 22%. At a dose of 23 ppm, sulfur dioxide reduced the fertility of aphids most significantly - by 30%. The data obtained indicate the influence of sulfur dioxide contained in the composition of fungal VOCs on the behavioral reactions of phytophages.

The e ect of VOCs of six entomopathogenic fungal strains from genus Lecanicillium on the behavioral responses of the western ower thrips females Frankliniella occidentalis on vegetative bean plants and in a Y-shaped olfactometer was studied. The signi cant repellent reactions of thrips females and a decrease in a number of o spring by 33-34% were revealed after treatment the beans by conidial suspensions of L. lecanii strains F2 and Vl 29 in the concentration of 1 × 107 spores/ml. Strains Vl 21 ( L. muscarium ) and Vit 71 ( L. attenuatum ), which showed a repellent tendency towards thrips females, also caused a signi cant decrease of o spring number. The strains isolated from aphids (ARSEF 2332 of L. dimorphum and Vl 13 of L. longisporum ) showed a tendency towards attractiveness. In the Y-shaped olfactometer the repellency of the F2 strain and the attractiveness of the ARSEF 2332 strain were con rmed. The in uence of the other studied strains on the thrips behavioral reactions was unreliable. Acetic acid, tested in the olfactometer at doses corresponding to its content in the fungal VOCs over growing mycelium, caused di erent reactions of thrips females depending on the acid concentration: attractive reactions at the dose of 0.17 ppm; neutral - at the dose of 0.34 ppm; and weak repellent - at 0.85 ppm. The obtained data indicate that acetic acid, contained in the fungal VOCs, e ect on the behavioral responses of thrips females. The repellant e ect of the fungal spores of the genus Lecanicillium on thrips females and the negative impact on o spring number increase the e ectiveness of entomopathogenic fungi.

Abstract—Bipolaris sorokiniana is circumglobally widespread root and leaf pathogen of cereals and grasses. It can grow both endo- and epiphytically and also survive in the soil. The chemical mechanisms of such good persistence of the fungus are poorly studied. This study assays the biological (phytotoxic, antimicrobial, insecticidal, and cytotoxic) activity of extracts from cultures of four B. sorokiniana of distinct geographical origin produced on three different media. The composition of media and, to lesser extent, origin of the isolate affected the yield of extractive matter, spectrum, and level of biological activity of extracts. Extracts from liquid culture mycelium demonstrated relatively high insecticidal activity to wheat aphid and galleria, while extracts from solid cultures were highly cytotoxic to the Sf9 cell line. Phytotoxic activity was the most pronounced in extracts from culture liquids. No correlation was found between phytotoxic and insecticidal or cytotoxic activity of extracts indicating possible production of insecticidal metabolites by B. sorokiniana isolates. The revealed insecticidal properties of the fungal metabolites were able to explain its high competition activity for the plant substrate and broaden the biotechnological potential B. sorokiniana of as a producer of bioactive compounds.

Investigation of the biological activity of Litsea cubeba essential oil and its main component citral to assess the possibility of their use in biologized protection of greenhouse crops was the aim of this research. The study was carried out on a laboratory population of the two-spotted spider mite on bean plants. The toxic action under the contact-intestinal application and fumigation, and repellent action against the spider mite females and their o spring were evaluated. When using L. cubeba oil and citral at a concentration of 0.25%, a signi cant decrease in the reproduction index by 2.8 and 2.5 times, respectively, was recorded. The activity of the essential oil under fumigation at doses of 7.5 and 6.0 μl/l of air was close to 100%. After reducing the dosage to 4.5 μl/l, the mortality in the experiment exceeded 50%, and the suppression rate of reproduction was 84.5%. The negative e ect on fertility remained above 60% at 3.75 μl/l. The citral application at a dosage of 3.0 μl/l resulted in the mite mortality above 80% and a decrease in the number of eggs laid by female by more than 90%. Females ignored leaves treated with 0.25% solutions of the studied substances, and the decrease in the number of eggs was more than 90% (repellent e ect). The use of citral at 0.125 and 0.06 % concentrations prevented the colonization of leaves by mites also, and at a concentration of 0.045 %, it reduced the number of eggs laid by 3.1 times. Thus, L. cubeba oil and citral may be perspective as natural acaricidal agents with di erent modes of action.

О ВЛИЯНИИ ЭФИРНОГО МАСЛА Litsea cubeba (Lour

О ВЛИЯНИИ ЭФИРНОГО МАСЛА Litsea cubeba (Lour

In evaluating the effectiveness of entomopathogenic fungi for control of the green peach aphid Myzus persicae (Sulzer, 1776), a dangerous pest and a virus vector, it is necessary to consider the effects of fungal spores and mycelium on the behavior of aphids related to host plant selection. In laboratory experiments, 5 out of 13 strains of different species of the genus Lecanicillium caused the repellency response in aphid females, with the index of aggregation varying from −22.7 to −39.7 and the number of nymphs in the daughter generation decreasing by 1.6–4.2 times. The species of fungi varied significantly in their ability to infect aphid nymphs: Lecanicillium longisporum was the most virulent against the green peach aphid, causing 89% nymphal mortality at a concentration of 1 × 107 spores / mL, while Lecanicillium psalliotae was practically non-pathogenic to aphids. All the strains showing significant repellency also possessed pronounced pathogenicity, while the opposite was not always true.

The study of fungal antibiotics in their competitive interactions with arthropods may lead to the development of novel biorational insecticides. Extracts of Alternaria tenuissima MFP253011 obtained using various methods showed a wide range of biological activities, including entomotoxic properties. Analysis of their composition and bioactivity allowed us to reveal several known mycotoxins and unidentified compounds that may be involved in the entomotoxic activity of the extracts. Among them, tenuazonic acid (TeA), which was the major component of the A. tenuissima extracts, was found the most likely to have larvicidal activity against Galleria mellonella. In the intrahaemocoel injection bioassay, TeA was toxic to G. mellonella and of Zophobas morio with an LT50 of 6 and 2 days, respectively, at the level of 50 µg/larva. Administered orally, TeA inhibited the growth of G. mellonella larvae and caused mortality of Acheta domesticus adults (LT50 7 days) at a concentration of 250 µg/g of feed. TeA showed weak contact intestinal activity against the two phytophages, Tetranychus urticae and Schizaphis graminum, causing 15% and 27% mortality at a concentration of 1 mg/mL, respectively. TeA was cytotoxic to the Sf9 cell line (IC50 25 µg/mL). Thus, model insects such as G. mellonella could be used for further toxicological characterization of TeA.

Secondary metabolites were isolated from cultures of four geographically distant isolates of the cosmopolitan fungus, Bipolaris sorokiniana for intense biological characterization. Analysis of extracts from their liquid and solid cultures with TLC and HPLC-MS showed high similarity of their composition despite on fungal origin. From the extracts of B. sorokiniana 14 metabolites (terpenes, quinones, xanthones etc.) were isolated using column chromatography and preparative HPLC; among them, 12 known substances were identified. Chloromonilinic acid B (CAB) showed the highest level phytotoxic activity on wheat leaves. The most of isolated compounds inhibited growth of Bacillus subtilis, of which methyl-8,3-hydroxy-3-methyl-4-chloroxanthon-1-carboxilate (MMC) demonstrated the strongest activity. Some metabolites of B. sorokiniana (CAB and MMC) were shown to have insecticidal activity against common cereal aphid. All the compounds were cytotoxic (especially, cochlioqionones and fusaroproliferin) when tested on Sf9 cell line. However, no one was acute toxic for infusoria. Evidently, the production of multiple bioactive compounds makes B. sorokiniana a strong competitor in different ecological niches and a dangerous contaminant of grain.

This paper presents comparative assessment of the reaction of the western flower thrips Frankliniella occidentalis and the predatory bug Orius laevigatus to the seed oil of Pongamia pinnata (L.) Pierre. This oil had repellent and toxic effects on the adult and larval thrips, and also reduced the number of laid eggs. The predatory bug O. laevigatus was highly sensitive to P. pinnata oil under various methods of exposure, even at a concentration of 0.75%, which was the lowest concentration effective against the thrips. The observed side effects of the oil on O. laevigatus determine the need either for development of a specific approach for combined use of the oil and this entomophage, or for replacing O. laevigatus with some other predator resistant to P. pinnata oil.

The effect of the spores of Akanthomyces and Lecanicillium species on the behavioral responses of the greenhouse whitefly Trialeurodes vaporariorum has been studied. Three strains of the species Akanthomyces muscarius, Lecanicillium pissodis and Lecanicillium dimorphum demonstrated a strong repellency and negative effect for the adult fecundity, causing the decrease of the eggs number up to 70 % in comparison with control. Two other strains of species L. psalliotae and A. muscarius did not affect the behavioral responses and fecundity of whitefly. All studied strains showed high virulence against whitefly larvae at concentration of 5 mln spores/ml causing mortalily rate between 76 and 98 % on the 7th day after treatment. The virulence of species L. dimorphum and L. pissodis was comparable with the virulence of the species A. muscarius, they are traditionally used to produce biopreparations against whitefly. They are promising for the whitefly control. Apparently, the behavioral responses of these pests should be considered for the evaluation of the pathogenic potential of entomopathogenic fungi.