Russian Journal of General Chemistry最新文献

Using self-propagating high-temperature synthesis with exothermic thermite-type mixtures, CoAl/W_xC and CoCuAl/W_xC composites were obtained. Based on ground composites, catalysts with a metallic active phase were prepared by aluminum leaching and stabilization. Their physicochemical characteristics and catalytic properties in CO₂ hydrogenation and deep oxidation of CO and hydrocarbons were studied. The Co/W_xC catalyst demonstrated 100% CO conversion at 250°C, and the maximum achieved propane conversion was 91% at 400°C. In the hydrogenation reaction, the maximum CO₂ conversion was reached at 350°C and amounted to 37%, while the methane yield fed passed CO₂ reached 32%.

Diketoesters were obtained by reacting dialkyl esters of perfluoroadipic and perfluoropimelic acids with alkyl ketones. The features of synthesizing polyfluorinated tetraketones via the reaction of dimethyl perfluorododecanedioate with alkyl ketones were studied. It was found that the use of THF increases the yield of tetraketones. Based on the results of non-empirical MP2/6-31G* calculations of possible stages of the process, details of the reaction mechanism were discussed.

Natural polymers encompass various classes of biologically important molecules that form the basis of living tissue and are involved in the metabolic processes of living organisms. Natural polymers play a diverse role in biological systems, making them a logical basis for developing means of protecting plants from phytopathogenic species—causative agents of diseases. Chitosan, an aminopolysaccharide with valuable physicochemical properties, biocidal and elicitor activity, and being safe for the environment, has proven itself well in this capacity. The polysaccharide nature of chitosan and the presence of reactive functional groups provide a wide possibility for its chemical modification, allowing the introduction of new properties to the polymer. This paper presents several approaches to creating plant protection products based on chitosan, including variations in molecular weight, colloidal-chemical state, and binding with biologically active modifiers via various mechanisms. In all cases, modified chitosan exhibited enhanced protective properties against plant pathogens.

Control systems for opium poppy (Papaver somniferum L.)—an undesirable narcotic-containing plant—must align with the principles of sustainable agriculture. Their priority is using biological agents and reducing the application of chemical pesticides. In the conducted research, the bioherbicidal activity and efficacy of a promising strain A. papavericola 1.39-8 in laboratory prototypes of mycoherbicides applied in combination with chemical herbicides to suppress Papaver somniferum L. were evaluated. Laboratory mycoherbicide prototypes alone caused mortality of up to 35%, and the severity of toxic damage to surviving poppy plants ranged from 24 to 67%: reductions in growth and biomass reached up to 60 and 65%, respectively. A significant increase in efficacy was recorded after a single combined application of a laboratory prototype based on A. papavericola 1.39-8 and sublethal doses of chemical herbicides based on the active ingredients metsulfuron-methyl and metribuzin. Mortality of test plants and losses in growth and biomass reached 99%.

This study presents results from a two-year monitoring program (2023-2024) on two key fungal diseases affecting potato: Alternaria blight (Alternaria solani Sorauer) and late blight (Phytophthora infestans (Mont.) de Bary). The research was conducted in the experimental field of the Federal State Budgetary Scientific Institution All-Russian Institute of Plant Protection (VIZR) in St. Petersburg. The spread and severity of these pathogens were analyzed in relation to specific agroclimatic conditions during the growing seasons, which determined their respective severity. Long-term meteorological data from the Hydrometeorological Center of the Russian Federation for St. Petersburg—which confirm a regional warming trend—were utilized. Our findings indicate that increasing average summer temperatures correlate with a rise in the damage potential of Alternaria blight in potato. By the end of the 2023 growing season, disease development exceeded 40%. Under very warm, sunny, and relatively dry conditions that year, yield losses from A. solani reached 22%. In contrast, late blight development was negligible in 2023. Conversely, during the hot but rainy 2024 season, no Alternaria blight symptoms were observed. However, late blight development reached 100% by the end of the growing season, resulting in yield losses of 73%.

The challenges of increasing crop productivity and improving harvest quality can be addressed by optimizing the phytosanitary status of agroecosystems and the application of effective and environmentally safe plant protection agents. This study investigated the effects of multifunctional biological preparations based on strains of antagonistic microorganisms of different taxonomic positions and their combinations with chitosan salicylate in the cultivation of spring soft wheat (Triticum aestivum L.). It was found that the application of multifunctional complexes based on strains of Bacillus subtilis, Streptomyces felleus S-8, Streptomyces sp. VIZR-18, and 0.1% chitosan salicylate significantly increased wheat productivity and yield (up to 147.8%) by increasing the number and length of primary and nodal roots, productive tillering, the number of spikelets, and the grain weight per spike. A significant reduction in plant disease incidence was observed: the biological efficacy against root rot was 50%, against Septoria leaf blotch 77.6%, and powdery mildew development was also significantly suppressed.

This study presented the possibility of joint application of plant compounds with attractant properties and compounds with repellent action, as elements of a push-pull strategy for thrips control in greenhouses on ornamental crops. The extracts from the Laurus nobilis L., Filipendula ulmaria (L.) and Tanacetum vulgare L. were studied. The laboratory tests revealed the attracting qualities of F. ulmaria and L. nobilis extracts. Using GC-MS, the presence of eucalyptol (1,8-cineole) was determined in the volatiles of all three extracts at that, in F. ulmaria this compound was predominant (52%). Field trials involving the combined use of attractant-baited traps (F. ulmaria and L. nobilis) showed the effectiveness of blue sticky traps with F. ulmaria extract. Application of 1% solution of T. vulgare extract with repellent effect (spraying of rose plants) resulted in the suppression of the pest population for a fortnight.

This study presents data on the biological activity of strain Streptomyces sp. VIZR-018, isolated from Crimean soil, against plant pathogens and phytophagous insects under laboratory and field conditions in the Stavropol region. The strain exhibited high antagonistic activity against a broad spectrum of phytopathogenic fungi and bacteria, insecticidal activity against a group of sucking arthropods, and phytoregulatory activity towards potato, cucumber, wheat, and barley plants. In field trials, pre-planting tuber treatment followed by two applications of a liquid formulation during the potato growing season had a stimulating effect on plant height (+64–71%), stem count (+30–33%), and the onset of flowering. The biological efficacy of the preparation against late blight development, compared to the farm’s standard protection system, ranged from 44.7 to 65.3%. As a result of treatment with the liquid Streptomyces sp. VIZR-018 sample, potato yield increased by 0.8–6.3 t/ha, equivalent to 9–68% compared to the control. In the laboratory, the strain demonstrated high insecticidal activity against the vetch aphid (Megoura viciae), with 100% mortality observed 4 h after treatment with the liquid sample.

A comprehensive comparative evaluation was performed to assess the effectiveness of various methods for the combined application of chitin, chitosan, and strains of the genus Bacillus for plant disease protection. The application of chitin and chitosan to soil—both individually and in combination with the B. subtilis VKM B-2604D strain—demonstrated significant efficacy in reducing the incidence of Fusarium wilt in tomato and cucumber plants. The most pronounced protective effect, characterized by a 2–3-fold reduction in disease incidence, was observed when these components were applied together. Application of a B. subtilis VKM B-2604D + chitin/chitosan formulation achieved a 1.7-fold reduction in the incidence of gray rot in tomato (cv. Kupets), whereas the B. subtilis VKM B-2604D strain alone reduced it by only 1.4-fold. Introducing colloidal chitin into the nutrient medium for the large-scale submerged cultivation of B. subtilis strains significantly enhanced their antagonistic activity against Alternaria solani and Clavibacter michiganensis. A formulation comprising B. subtilis VKM B-2604D and VKM B-2605D with colloidal chitin exhibited a higher fungistatic effect against Cochliobolus sativus compared to the original strain. Foliar application of B. subtilis VKM B-2604D and VKM B-2605D + colloidal chitin formulation increased wheat resistance to dark brown spot and brown rust by 1.5–2.0 times compared to the original strains. The hydrolysis of colloidal chitin by bacterial chitinases yields chitooligosaccharides, which serve as effective elicitors of induced plant resistance. These compounds activate genes encoding protective proteins, including plant chitinase, and enhance the generation of reactive oxygen species, primarily H₂O₂. Hydrogen peroxide, in turn, functions as a signaling molecule, activating protein genes through redox control of transcription factors or via interaction with other signaling components. This study demonstrates that formulations based on chitin, chitosan, and selected active strains of endophytic antagonistic bacteria hold considerable promise for developing novel biopreparations with enhanced biological efficacy that strengthen plants’ natural defense responses.

The environmentally safe application of pesticides requires a detailed understanding of their behavior under specific agroclimatic conditions. Pyraclostrobin, a member of the strobilurin class, is a contact fungicide that is absorbed into the plant cuticle without systemic translocation, forming a reservoir of the active substance on the surface. Beyond its direct action on pathogens, pyraclostrobin can delay crop senescence, accelerate the synthesis of resistance-related proteins, promote plant growth, and enhance overall immunity and stress tolerance. The objective of this study was to investigate the degradation dynamics of pyraclostrobin across various agricultural crops and under different natural-climatic zones. The results demonstrate a consistent degradation pattern for pyraclostrobin across the studied crops. The compound exhibited a half-life of approximately one week post-application. Within two weeks, residues were typically at or below the method's limit of quantification (LOQ). At harvest, residues were below the established maximum residue level (MRL) for grapes and were not detectable in other crops. In conclusion, pyraclostrobin demonstrates a broad application spectrum, high efficacy in disease control, and a safety profile that ensures consumer protection.