Infestation Of Crops Research Articles

The use of broadband vegetation indices to assess the weed infestation of crops

The use of broadband vegetation indices to assess the weed infestation of crops

Influence of the level and duration of infestation of crops on rice yield

Goal. Determine the effect of the number and duration of the period of presence of weeds in rice crops on the level of yield.
 Methods. We used general approaches to the study of the phytosanitary state of agrocenoses: herbological, laboratory-field, calculated, mathematical-statistical. Weed exposure studies were performed at 10, 20 and 30 pieces of chicken millet/1 m2, competition period — 20, 40, 80 days, and before harvest. Option of pure sowing, as well as all types of weeds without weeding and without treatments. Weeds were recorded at the same time as other pests at the same sites at the appropriate times. The number of weeds by species and their total number were counted, and their height, phase of development and biomass were determined. During the growing season, the increase in raw weed mass and rice yield were determined. The size of the experimental and accounting area is 1 m2, rice variety Ukraine 96.
 Results. The most competitive species for nutrients and light on rice crops are representatives of the genus Echinochloa. There are different data regarding the decrease in rice yield from the number of weeds and the duration of their competition in crops. In the literature there are references that the level of infestation with chicken millet in the amount of 30—40 plants per 1 m2 reduces the yield by 10—15%, an increase in the number to 200 or more plants per 1 m2 leads to a decrease in yield by 50 % or more. In 2016—2018 In the experiment, the number of weeds was formed, which is the most competitive in obtaining a harvest of rice on the territory of Ukraine — chicken millet (ELH 10 pcs/m2). Studies of the influence of weediness were carried out at the number of 10, 20 and 30 pcs/1 m2, the competition period was 20, 40, 80 days and before harvesting, as well as the option of clean sowing. It was found that the yield of rice is negatively affected by both the number of weeds and the duration of infestation (competition). The dependence of the weight of rice grain on the weight of weeds was studied without the formation of the number, that is, all that were present in the sowing from the moment of germination in different periods (20, 40, 80 days) and before harvesting.
 Conclusions. Rice yield losses were determined with different numbers of chicken millet and different duration of joint growth, peculiarities of growth and development of chicken millet under competitive conditions, general soil contamination in rice paddies. The minimum losses in comparison with clean crops are 5.8 %, provided that the number of chicken millet is 10 pcs/m2, and the duration of the competition is only 20 days. With the number of 10 pcs/m2, 20, 30 pcs/m2 of chicken millet, and their competition before harvesting, the losses are — 68.7%, 81.4% and 73.9%, respectively, in comparison with clean crops. An increase in weed weight is directly proportional to a decrease in grain weight. A reliable strong relationship was established between an increase in the mass of weeds and the mass of grain r = –0.901.

The effect of root rot on the yield of durum wheat grain in the conditions of the Orenburg region

The identification of factors that affect the decrease in the yield of hard wheat is the basis for studying plant diseases in the agrometeorological conditions of the Orenburg region. In this regard, field and laboratory studies are being conducted on common root rot (Bipolaris sorokiniana) of durum wheat. In the research work, the method of field experience was applied, the weather factors, the infestation of crops with root rot and the yield of durum wheat grain in crop rotations and during permanent cultivation in the southern black lands of the Urals were taken into account. The research was carried out for the first time from 2015 to 2020 on a long-term stationary experimental plot on crop rotations and permanent crops, laid down in 1988 on the territory of the OPH n.a. Kuibyshev. On average, during the growing season of the crop (durum wheat), 107 mm of precipitation falls at an average monthly air temperature of 20.3 oC and the number of dry days is 68. The results of the study show that the lowest prevalence and development of root rot reaches 28.6 and 10.2 % in the third variant of the experiment on a non-windy background of nutrition, the dependence on the influence of air temperature is 94.4 and 70.0 %. The highest yield of durum wheat grain was obtained in the fallow field with siderates in the average arid year of 2017 and amounts to 2.14 and 2.11 t / ha after the application of mineral fertilizers and without them. In the fourth version of the experiment, there is a decrease in the yield of durum wheat grain, which depends on the development of root rot at the maximum proportions of the influence of 80.0 and 89.7 %. Various agro-meteorological conditions, precursors and food backgrounds are the main cause of changes in the degree of spread and development of durum wheat root rot.

The influence of the protectant and mineral fertilizers on the contamination of crops and the disease infestation of hemp sowing plants

The research was conducted during 2017-2020 at the experimental field of the Federal Research Center for Bast Fiber Crops the Penza region. The results of laboratory and field experiments to determine the effectiveness of seed treatment with TMTD, VSK and Izagri Force fertilizer, as well as spraying with Izagri Phosphorus fertilizer of plants of monoecious hemp of the Nadezhda variety are shown. The studied factors influenced the seed contamination and the prevalence of root rot, and later on the infestation of crops and the intensity of leaf spot development. Seed treatment with TMTD, VSK (5.0 and 2.5 l/t) suppressed 95.3 and 85.5 % of seed infection, reduced the prevalence of root rot by 4.2 and 1.8 %, and the intensity of leaf spot development by 1.3 and 0.6 % compared to the control. A significant effect of the studied factor on the reduction of the air-dry mass of weeds in the phase of 6-7 pairs of leaves was proved by 31.9 and 26.4 % compared to the control. When using Izagri Force fertilizer for seed treatment (1.0 and 0.5 l / t), the biological efficiency of etching was 47.2 and 37.0 %. The prevalence of root rot decreased by 1.8 and 5.4 %, respectively, and the intensity of leaf blotches decreased by 1.6 and 1.1 % compared to the control. The application of the fertilizer allowed to reduce the air-dry mass of weeds in the phase of mass maturation of hemp seeds by 4.8 and 6.5 % compared to the control. Foliar top dressing with Izagri Phosphorus fertilizer for plant vegetation (3.0 l / ha) provided a reduction in the air-dry mass of weeds on average during the growing season by 17.4 % compared to untreated plants. The combination of all the studied factors when using TMTD, VSK and Izagri Force preparations in the consumption rates of 5.0 and 1.0 l / t against the background of foliar top dressing led to the suppression of weed vegetation, respectively, by 48.1 %.

Phytotoxicity of aqueous extract of Ilex paraguariensis A.St.-Hil on Conyza bonariensis (L). Cronquist

Crop infestation species have acquired resistance to herbicides, stimulating the search for new control methods. Plants secondary metabolites can hold more sustainable alternatives, as they can be used for development of natural herbicides. This study evaluated phytotoxic effects of aqueous extracts of Ilex paraguariensis leaves on Conyza bonariensis, an infesting species of Brazilian crops. Different concentrations of decoction and infusion extracts were tested in germination and growth bioassays. Adult plants were evaluated for leaf anatomy effects caused by the yerba mate extract. HPLC analysis was used to quantify the three major chemical constituents. The most effective aqueous extract (decoction 1.0%) decreased the percentage of seed germination, germination speed index, and percentage of germination-derived seedling formation, and increased the time for seedling formation. Shoot and root growth were not affected by this extract. In adult plants, the same extract damaged epidermis and palisade/lacunous parenchyma six hours after exposure. Caffeine was found as the major compound of this extract, followed by rutin and quercetin. Therefore, aqueous extract by decoction 1.0 % of I. paraguariensis leaves showed potential for control of C. bonariensis infestation and rather promising for the development of a natural herbicide.

The effect of herbicides on the infestation of winter wheat crops

Weed vegetation is a serious competitor to cultivated plants. Weed vegetation spends important elements and moisture on its vital activity, thereby reducing the yield. Weed control is an important element of the cultivation technology of any agricultural crop. Winter wheat is the main important crop in the South of Russia, the yield of which affects the quality of life of the population. The use of herbicides is the basis of protective measures against weeds. Modern trends in the development of the agro-industrial complex recommend a reduction in pesticide treatments, however, there is no other alternative for weed control. Our research is aimed at studying the biological effectiveness of herbicidal treatments and their effect on the development of weeds.

Complex of agrotechnical methods for different varieties of winter wheat

Increasing grain production and improving its quality are of great importance for our country. A special role is given to winter wheat as a highly productive and valuable food crop, which occupies about 2 million hectares in the Central Black Earth Region. Winter wheat also occupies significant areas in Belgorod region, which, according to agroclimatic zoning, is included in the zone of unstable moisture. Under these conditions, the development and opening up resource-saving adaptive technologies for the cultivation of crops, in particular winter wheat, as the most important grain crop, which would be assessed not only by productivity, but also by the degree of anthropogenic load on ecological systems, are of particular importance. The aim of the research is to change the agrophysical and biological properties of the soil, weed infestation of crops, yield and quality of different varieties of winter wheat, depending on preceding crops, new types of fertilizers and growth regulator. In this work, for the first time for the Central Black Earth Region, the complex effect of preceding crops, new types of fertilizers and growth regulator on changes in agrophysical, biological properties of soil, yield and quality of cultivated varieties of winter wheat Maiskaya Yubileinaya and Almera was studied. A complex of agrotechnical techniques for different varieties of winter wheat, identified on the basis of the research results, based on the use of optimal preceding crops, new types of fertilizers and plant growth regulators, allows the development of energy and resource-saving technologies of the cultivated crop. The expediency of using the most adaptive for the conditions of the region combination of agricultural practices for promising varieties of winter wheat is shown.

Developing Functional Genomics Platforms for Fungi.

ABSTRACTFungi are responsible for diseases that result in the deaths of over a million individuals each year and devastating crop infestations that threaten global food supplies. However, outside of a select few model organisms, the majority of fungal genes are uncharacterized. The roles of these genes in the biology of the organism, pathogenesis, and mediating interactions with the environment and other microbes are unknown. Historically, fungal gene characterization has primarily relied on classical genetic screens. However, advances in sequencing technology have enabled more rapid methods of gene functional characterization. Large-scale transcriptional profiling projects are one solution to generating hypotheses about fungal gene function. Together with other ‘omics techniques and newer tools that enable massively parallel mutant screens, knowledge of fungal gene function will be substantially improved. Understanding the function of fungal genes will be instrumental in increasing global food security, protecting ecosystems, and improving health outcomes.

ВЛИЯНИЕ СРЕДСТВ ХИМИЗАЦИИ НА ОПТИЧЕСКИЕ СВОЙСТВА АГРОЦЕНОЗА ЯРОВОГО ЯЧМЕНЯ С ПОДСЕВОМ МНОГОЛЕТНИХ ТРАВ

The purpose of the research was to study the effect of mineral fertilizers and plant protection system on the vegetation index NDVI and its seasonal dynamics in agrocenoses of spring barley with overseeding of perennial grasses in the North-West of Russia. The data obtained indicate that against the background of the deficiency of the main elements of mineral nutrition in the second half of the growing season of spring barley, a significant phytomass of perennial grasses is formed in the crop, which account for 36.7%. This leads to a smaller decrease in the NDVI index (by 0.06) than in the fertilized variants (0.20). The value of NDVI index reflects not only the state of cultivated plants and weed infestation of crops, but also the level of development of crops, growing under vegetation. The influence of mineral nutrition developed during the period of maximum values of the index, which were recorded 6-8 weeks from the sowing date and 26-30 weeks from the beginning of the year. Under the influence of average doses of fertilizers, the NDVI index increased by 0.09...0.2 (on average 0.13), under the influence of high doses – by 0.13...0.26 (on average 0.18). The influence of plant protection system was expressed by a decrease in the phytomass of weeds (by 49.4...68.9%), at the same time the mass of spring barley and perennial grasses increased (by 1.7...18.5% and by 11.7...43.5% respectively). Carrying out the whole complex of protective measures led to a decrease in the NDVI index values by 0.01...0.06, depending on the phytosanitary situation in the agrocenosis. The most reliable forecast of the yield of spring barley can be implemented in the period from 5 to 7 weeks from the beginning of the emergence of barley shoots, especially against the background of the use of plant protection products that eliminate the influence of harmful organisms on the formation of the crop and the optical properties of crops

Bis- and mono-substituted Chalcones exert anti-feedant and toxic effects on fall armyworm Spodoptera frugiperda

Spodoptera frugiperda is a highly polyphagous migratory lepidopteran pest species. It causes infestation in crops leading to the severe crop losses. Being a new invasive parasite, its susceptibility to insecticides needs to be explored; and therefore, there is an urgent need to develop the potent insecticides for the effective control of this insect pest. To attain the crop sustainability, the antifeedant, toxicity and nutritional effects on larvae of Spodoptera frugiperda were studied with six mono- and eight bis- substituted chalcones. The antifeedant activity was calculated when 50% of the larvae control ate 50% of the diet through the FR factor. Toxicity was assessed through larval, pupal mortality and the emergence of adults and nutritional effects with consumption rates (IC), growth (GR) and consumption efficiency (EIC). The bis-chalcones 6b, 6e, 6f and 6h caused lethal effect on S. frugiperda in the first larval stages, being 6b the most toxic (85%). Adults who survived showed malformations and decreased size, which led to death. The larvae fed with aggregate in the bis-chalcones diet: 6b, 6e and 6f had the highest percentage of intake and the poorest conversion of nutrient absorption (ECI), which suggests that the larva metabolizes food for energy and results in a decrease of growth and death in early stages. Bis-chalcones showed more toxicity than mono-chalcones and 6b causes the most toxic and dietary change.

Testing of herbicidal systems for maize cultivation in the Steppe of Ukraine

Goal. To determine the agrarian and economic efficiency of different technological systems for herbicidal protection of maize depending on the weed harmfulness level and weather conditions.
 Methods. Field experiment — for the weeds and maize yield accounting, and calculation method — for determining of the technical and economic efficiency of herbicide systems.
 Results. We recorded a significant decrease in the inhibitory effect of soil herbicides without precipitation, at elevated air temperature and hot dry wind in the first 5—7 days after their application. Also we specified the best pre-emergence herbicide Acris SE containing the active ingredients: Dimethenamid P (280 g/l) + Terbuthylazine (250 g/l). The number of weeds was indicated according to the experiment variants before spraying crops and 21 days after the application of toxicants. The technical and economic efficiency of combined (pre-emergence + post-emergence herbicides) and mixture of post-emergence products for protection systems of maize was determined.
 Conclusions. Under arid conditions, within 5—7 days after the application of pre-emergence herbicides (in 2018, the average background weed infestation of crops — 37 pcs/m2), the chemical plant protection system based on a tank mixture of post-emergence herbicides was ahead in terms of technical efficiency, yield and profitability grain production: Frontier Optima CE (Dimethenamid, 720 g/l) + Stellar RK (Topramezone, 50 g/l + Dicamba, 160 g/l) + Metolat wetting agent. The manifestation of soil herbicide phytotoxicity in favorable weather (in 2019—2020, background weed infestation of crops 129—147 pcs/m2) was more effective when using a combined system for controlling harmful species in the maize production technology: Dual Gold KE (S-metolachlor, 960 g/l) — before sowing + Stellar RK (Topramezone, 50 g/l + Dicamba, 160 g/l) + Metolat wetting agent — post emergence application. The best pre-emergence chemical product was Acris SE (Dimethenamid P, 280 g/l + Terbuthylazine, 250 g/l).

The reasons for the decrease in the feld crops yield against the background of flat-cut basic tillage

The purpose of the research was to establish the reason for the decrease in the productivity of crops grown in the experiments under replacing the main processing of moldboard plowing with flat-cut loosening to appropriate depths based on a review of the literature and our own experiments conducted on podzolized chernozem in a fve-feld crop rotation of soybeans – spring rape – spring wheat – oil flax – spring barley. According to the research data, the average yield of 15 crops decreased by 9.0 % due to such replacement. In our experience, the average yield of spring crops decreased by the same amount. Such a decrease in the yield of crops cultivated in different experiments against the background of flat-cut cultivation instead of plowing could not be caused by a deterioration in the physical condition of the soil due to the absence of the latter, sinse in 15 experiments, according to the literature data, the density of the addition of the arable layer of different soils changed only by 0.7 % and the content of agronomically valuable structures – only by 0.1 %, and in our experience – respectively by 2.1 and 1.4 % (towards improvement). The total soil permeability in the arable layer also decreased by 1.9 % in our study due to the use of flatcut tillage instead of fall plowing, while remaining within the acceptable range. Changes in the water regime related to the change in the method of basic soil cultivation could not negatively manifest at the level of productivity of crops cultivated in different experiments. In addition, only in fve publications out of 15 the reserves of available moisture in the root layer decreased due to replacing moldboard cultivation with non-moldboard loosening, and in the rest 10 ones they remained unchanged or they increased signifcantly. Therefore, the reserves of soil moisture available against the background of flat-cut loosening were 1.7 % higher in comparison with plowing. In the experiment, the advantage of flat-cut cultivation over plowing in terms of available moisture reserves in a meter layer of soil at the middle and end of the growing season of spring crops increased to 6.1 and 6.4 %, respectively. The average productivity of crops cultivated in crop rotation against the background of flat-cut cultivation was signifcantly (by 9.0 %) lower in comparison with plowing. The reason for this could be almost a third (by 27–31 %) higher infestation of crops after the moldboard-free main autumn tillage. Key words: fve-feld crop rotation, physical condition of the soil, reserves of available moisture, crops weediness, crop yield.

Achieving Sustainability in Food Systems: Addressing Changing Climate through Real Time Nitrogen and Weed Management in a Conservation Agriculture-Based Maize–Wheat System

The proven significance of conservation agriculture (CA) in enhancing agronomic productivity and resource use efficiency across diverse agro-ecologies is often challenged by weed interference and nitrogen (N) immobilization. The collective effect of real-time N and weed management has been scarcely studied. To evaluate the appropriateness of sensor-based N management in conjunction with a broad-spectrum weed control strategy for the maize–wheat system, an experiment was conducted at ICAR—Indian Agricultural Research Institute—in New Delhi, India, during 2015–2016 and 2016–2017. Weed management in maize through Sesbania brown manure followed by post-emergence application of 2,4-D (BM + 2,4-D) in maize and tank-mix clodinafop-propargyl (60 g ha−1) and carfentrazone (20 g ha−1) (Clodi+carfentra) in wheat resulted in minimum weed infestation in both crops. It also resulted in highest maize (5.92 and 6.08 t ha−1) and wheat grain yields (4.91 and 5.4 t ha−1) during 2015–2016 and 2016–2017, respectively. Half of the N requirement, when applied as basal and the rest as guided by Optical crop sensor, resulted in saving 56 and 59 kg N ha−1 in the maize–wheat system, respectively, over 100% N application as farmers’ fertilizer practice during the two consecutive years. Interactive effect of N and weed management on economic yield of maize and wheat was also significant and maximum yield was obtained with 50% N application as basal + rest as per Optical crop sensor and weed management through BM+2,4-D in maize and Clodi+carfentra in wheat crop. The study concludes that real-time N management, complemented with appropriate weed management, improved growth, enhanced agronomic productivity and endorsed N saving under a CA-based maize–wheat system in Trans Indo-Gangetic Plains.

Production of bio-fungicide, Trichoderma harzianum CH1 under solid-state fermentation using coffee husk

A novel and effective bio-fungicide, Trichoderma harzianum CH1 was isolated earlier and characterized for its potential to prevent infestation of pepper and ginger crops by phytopathogens like Phytophthora spp., Rhizoctonia spp., and Fusarium spp. Response surface methodology based central composite design has been applied with T. harzianum on coffee husk (lab-scale, 10 g of substrate) for optimizing the fermentation parameters for enhancing biomass production. The bioprocess parameters such as temperature, moisture content, carbon sources and ammonium sulphate were optimized. A combination of temperature (30 °C), moisture content (67.5% v/w), jaggery (2% w/v), and ammonium sulphate (2% w/v) was found optimum for maximum production. The biomass yield of 143.24 mg/gram of dried fermented substrate was 2.05 times the yield on the optimized conditions by the one-factor-at-a-time method and 3.64 times of the randomly selected conditions. Enhanced production of T. harzianum has great potential to be developed as substitute of toxic fungicides.

Exploring the dermotoxicity of the mycotoxin deoxynivalenol: combined morphologic and proteomic profiling of human epidermal cells reveals alteration of lipid biosynthesis machinery and membrane structural integrity relevant for skin barrier function

Deoxynivalenol (vomitoxin, DON) is a secondary metabolite produced by Fusarium spp. fungi and it is one of the most prevalent mycotoxins worldwide. Crop infestation results not only in food and feed contamination, but also in direct dermal exposure, especially during harvest and food processing. To investigate the potential dermotoxicity of DON, epidermoid squamous cell carcinoma cells A431 were compared to primary human neonatal keratinocytes (HEKn) cells via proteome/phosphoproteome profiling. In A431 cells, 10 µM DON significantly down-regulated ribosomal proteins, as well as mitochondrial respiratory chain elements (OXPHOS regulation) and transport proteins (TOMM22; TOMM40; TOMM70A). Mitochondrial impairment was reflected in altered metabolic competence, apparently combined with interference of the lipid biosynthesis machinery. Functional effects on the cell membrane were confirmed by live cell imaging and membrane fluidity assays (0.1–10 µM DON). Moreover, a common denominator for both A431 and HEKn cells was a significant downregulation of the squalene synthase (FDFT1). In sum, proteome alterations could be traced back to the transcription factor Klf4, a crucial regulator of skin barrier function. Overall, these results describe decisive molecular events sustaining the capability of DON to impair skin barrier function. Proteome data generated in the study are fully accessible via ProteomeXchange with the accession numbers PXD011474 and PXD013613.

An automatic pesticide sprayer to detect the crop disease using machine learning algorithms and spraying pesticide on affected crops

In the face of a focus on development, a farming residue a most powerful sector of an Indian financial management system both regarding the benefaction to gross domestic product (GDP) and also the source of utilization to the billions of people across the country. Agriculture is an agribusiness of the farmer that take part in the Indian financial management system. More than 75 percent of farm households depend on agriculture for their livelihood. But pest infestation in crops is a serious problem that slows down the growth of agricultural production. Crop disease identification in the agricultural sector is essential to deal with such problems. This present paper provides a technical solution to solve the type of issue in which the CNN algorithm is used to diagnose crop diseases and involves automatic pesticide spraying to spray pesticides on the affected crops locally. The system is based on pesticide sprays. The design deals with three modules image acquisition, image pre-processing, image segmentation, feature extraction, and classifications, and automatic spraying pesticide on the crop. The suggested system can work from a distance with a laptop with the help of a VNC viewer and Python IDLE.

Classification of Plant Electrophysiology Signals for Detection of Spider Mites Infestation in Tomatoes

Herbivorous arthropods, such as spider mites, are one of the major causes of annual crop losses. They are usually hard to spot before a severe infestation takes place. When feeding, these insects cause external perturbation that triggers changes in the underlying physiological process of a plant, which are expressed by a generation of distinct variations of electrical potential. Therefore, plant electrophysiology data portray information of the plant state. Analyses involving machine learning techniques applied to plant electrical response triggered by spider mite infestation have not been previously reported. This study investigates plant electrophysiological signals recorded from 12 commercial tomatoes plants contaminated with spider mites and proposes a workflow based on Gradient Boosted Tree algorithm for an automated differentiation of the plant’s normal state from the stressed state caused by infestation. The classification model built using the signal samples recorded during daylight and employing a reduced feature subset performs with an accuracy of 80% in identifying the plant’s stressed state. Furthermore, the Hjorth complexity encloses the most relevant information for discrimination of the plant status. The obtained findings open novel access towards automated detection of insect infestation in greenhouse crops and, consequently, more optimal prevention and treatment approaches.

Influence of herbicides and their tank mixes on infestation of spring barley crops

Influence of herbicides and their tank mixes on infestation of spring barley crops

Вплив основного обробітку ґрунту та удобрення на забур’яненість посівів соняшнику

The influence of basic tillage and fertilizer on weediness of sunflower crops The article presents the influence of the basic tillage and fertilization system on weediness of sunflower crops in the stationary crop rotation during 2016–18 in the conditions of the eastern part of the Forest-Steppe of Ukraine. The largest number of species of weeds and contaminants in crops was found on the background without fertilizers (plowing) and on the organic-mineral intensive background (manure aftereffect, 30 t / ha + N30P30K30, chiseling). The type and level of weed infestation of sunflower crops significantly depended on the studied factors. Keywords: sunflower, crop rotation, tillage, fertilizers, weeds, herbicides.

ФИЛОАГРОЦЕНОГЕНЕЗ В ПОСЕВАХ САХАРНОЙ СВЕКЛЫ ПРИ РАЗНОЙ СТЕПЕНИ АНТРОПОГЕННОЙ НАГРУЗКИ В ХХВЕКЕ–НАЧАЛЕ ХХI ВЕКА

The south of the Non-Chernozem Region is the north-ern boundary of sugar beet production in the Russian Fed-eration. An important factor restraining the growth of crop productivity is the high weed infestation of crops. To devel-op an effective system of crop protection against weeds, it is necessary to study their species composition in order to determine the most occurring and noxious weed species. The available data of geobotanical surveys since the 1930s showed that at different levels of anthropogenic impact the core of the most noxious weed species was formed. Under extensive agriculture conditions, the following species were the most widespread ones: Elytrigia repens(L.) Nevski, Equiseeum arvenseL., Sonchus arvensis L., Convolvulus arvensisL., Cirsium setosum(Willd.) Besser., Artemisia absinthiumL., Chenopodium albumL., Polygonum avicula-reL., Apera spica-ventiL., etc. The introduction of mechan-ical plowing decreased the population density of A. spica-ventiL., Dracocephalum thymiflorumL., and P. aviculareL. Further intensification of agriculture contributed to the narrowing of the weed species composition. Avena fatuaL., not previously found, appeared in abundance in crops and surpassed all other species in terms of number and frequency of occurrence, as well as species resistant to herbicides from the 2.4-D dimethylamine group -Poaceae, Galium aparineL., Tripleurospermum inodorum(L.) Sch. Bip. Couch grass(Elytrigia repens(L.) Nevski) was com-pletely substituted. Currently, the agrophytocenoses con-tain the most harmful rhizome and root-sucker weeds and spring species. Thefollowing early spring weeds are par-ticularly harmful and highly spread in crops: common wild oat (Avena fatuaL.), hemp-nettle species (Galeopsis), and Chenopodium albumL.; overwintering weeds resistant to 2.4-D dimethylamine which seeds accumulate in the soil during the cultivation of other crops in crop rotations where weed control is not so intense.