The results of evaluation the biological and economic efficiency of herbicides Lazurite Ultra, SC and Sencor Ultra, SC at different times of application in potato plantings are presented in the article. High herbicidal activity of metribuzin-containing preparations against annual dicotyledonous weeds (98.0–100 %) has been noted by two times application (before germination and on potato seedlings at a height of up to 5 cm), as well as against annual grass weeds (83.6 to 98.4 %) by spraying on 5 cm potato seedlings, having been preserved for two months

The results of researches on the regulation of barnyard grass (Echinochloa crus-galli (L.) Beauv.) number in sugar beet crops with the use of graminicides based on quizalofop-P-ethyl, haloxyfop-P-methyl, fenoxaprop-P-ethyl, cletodim and tank mixtures of cletodim + haloxyfop-P-methyl are presented. The use of herbicides in a month after treatment has made it possible to reduce the crops infestation for 96,4–100 %, preserving the root crops yield and getting additionally from 138–200 to 493–558 cwt/ha of beet roots (depending on barnyard grass number), significantly increasing sugar yield. No negative effect on growth, crop development and technological root crops characters has been noticed.

The data on the effectiveness of post-emergent herbicides Corum , WC + SAS DASH (1,5+1,0 l/ha), Pulsar, AS (1,0 l/ha), Basagran, AS (3,0 l/ha) and Hermes, OD (0,9 l/ha) in the agrocenosis of fodder beans are presented in the article. It is determined that crops spraying at 1–3 leaves of the crop stage and the early stages of weed development has made it possible to preserve 5,9–9,6 cwt/ha of fodder beans grain depending on the experimental variant, ensuring getting the conditional net profit of 23,2–228,4 rbl/ha with a profitability level of 65,5–228,4 %.

The article presents the route survey results on sugar beet crops weed infestation in the Republic of Belarus. Information is given on the species and quantitative composition of weed cenosis. The dynamics of its changes from 1995 to 2015 and the reasons for their causes has been studied. A tendency has been determined in the formation of a highly specialized annual dicotyledonous-grass weed cenosis in sugar beet crops.

The biological and economic efficiency of the herbicide Soil, WDG (metribuzin, 700 g/kg) against annual dicotyledonous and grass weeds is shown. The herbicide Soil, WDG is not effective enough against Elytrigia repens, Sonchus spp., Artemisia vulgaris, Galium aparine, Viola arvensis. Therefore, tank mixtures of herbicides, derivatives of metribuzan, with herbicides of other groups or their sequential application are recommended.

It is shown that the weed flora in winter grain crops (rye, wheat, triticale) in Belarus is formed by species from Meadow grass, Aster, Pink, Plantain families.

The herbological database provides the centralized storage of information on specific composition of weeds, their harmfulness in corn crops, depending on the technology of its cultivation and the preparation of an assortment for its protection, which ensures an increase in the efficiency of measures to protect crops against weeds.
The database includes information on active ingredients, herbicides and their application rates, data on the number and specific composition of dominant weed species in corn crops, biological thresholds of weed harmfulness.

Herbicides Extracorn, ES and Saturn Duo, MD are included in the State Register of Plant Protection Products (Pesticides) and Fertilizers permitted for Use on the Territory of the Republic of Belarus. The consistent application of herbicides Extracorn, ES (4,0 l/ha) or Saturn Duo, MD (1,5 l/ha) in early spring on weeds seedlings and Tornado 500, AS (2,0 l/ha) with the appearance of a new wave of weeds has allowed keeping the apple orchard near-stem strips in practically pure state throughout the entire growing season.
From the economic point of view, a system of protection against weeds using the herbicides Extracorn, ES (4,0 l/ha) + Tornado 500, BP (2,0 l/ha) is 16,3 % cheaper than Saturn Duo, MD (1,5 l/ha) + Tornado 500, BP (2,0 l/ha).

The results of studying the possibility of using the herbicides Terrsan, WDG and Sencor Ultra, SC to protect red chokeberry plantations against weeds are presented. It is determined that the application of the preparation Terrsan, WDG (750 g/kg of sulfometuron-methyl acid) in early spring before the beginning of the crop growing season at the rate of application 30 g/ha makes it possible to keep the bush side stripes practically free from weeds for 60 days. The biological efficiency of Sencor Ultra,SC (metribuzin, 600 g/l) at the rate of application 0,6 l/ha against perennial weeds has made 62,0–65,0 %, and against annual weeds has reached 98,0 %. The negative effect of the preparations on the crop has not been observed.

Herbicides based on the active ingredient prometryn (700 g/l) – Gezagard, SC, Prometrex Flo,SC and Gambit, SC (1.5–2.0 l/ha) with the application after sowing before milk thistle seedlings emergence have a high biological effectiveness against annual dicotyledonous and grass weeds. The application of soil herbicides has been the most effective under wet weather conditions. Volunteer rape, Capsella bursa-pastoris, Galinsoga parviflora, Spergula arvensis have died for 90-100 %; Matricaria perforate, Thlaspi arvense, Chenopodium album, Stellaria media – for 80–90 %; Polygonum scabrum and Polygonum convolvulus – for 70–80 %; Echinochloa crus-galli and Viola arvensis – for 60–80 % depending on the rate of application and weather conditions.

Studies have been carried out to assess the sensitivity of the fungus V. inaequalis to the preparation cresoxim-methyl from the strobilurin group by the method of conidia germination and the molecular-genetic method (detection of G143A mutation). A decrease of the apple scab causative agent sensitivity to cresoxim-methyl in the industrial gardens with the annual one-two-time application of preparations from strobilurins in the garden protection system has been revealed. It is determined that 4-fold sequential application in the garden of the fungicide Strobi, 500 g / kg w. leads to 8.9 times loss of the fungus V. inaequalis sensitivity to cresoxim-methyl compared to the control. In the populations of the fungus V. inaequalis, by PCR-RFLP method the isolates with the G143A mutation have been revealed, determining them as resistant to cresoxim-methyl.

The article describes the species composition of rot pathogens of garden carrot root crops during storage in Belarus. It is determined that in the phytopathogenic complex structure white rot causative agent - the fungus Sclerotinia sclerotiorum is dominant. The cultural and morphological characteristics of phytopathogenic micromycetes are described. The influence of abiotic factors on rot pathogens growth has been studied and a wide adaptive potential of the studied phytopathogens is shown.

The results of a long-term phytosanitary state of tubers evaluation against the background of potato protection against late blight during the growing season are presented. It is found that during harvesting late blight incidence on tubers with the use of single-component fungicides has made, on the average, 2,5 %, two-component fungicides – 2,3 %. Spring phyto-examination of potato tubers has shown the annual presence of oomycete in the combination with the other pathogens of bacterial and fungal etiology. The late blight-fusarium-bacterial type of mixed rot has turned out to be the dominant one, the prevalence of which has made 5,0 %. The long-term protective effect of combined fungicides in reducing the degree of late blight potato tops damage has been determined, exceeding 60,0 % in 30 days after the last application.

During vegetation of spring and winter grain cereals the modern two-component insecticides with a high efficiency against the dominant pests have been studied. By spring barley treatment during vegetation against the main phytophages for the period of 2008–2019 the most effective have been the variants with the application of two–component insecticides based on imidaclopride in a combination with the pyrethroid: in reducing stems damage by Frit flies – 80–100 %, against cereal stem flea beetles – 85,7–100 %, against cereal leaf beetle larvae – 83,7–100 %, cereal aphids – 91,4–100 %, ensuring crop productivity increase for 9,8 %. The biological effectiveness of the preparations used on the basis of neonicotinoids and synthetic pyrethroids against cereal leaf beetle larvae has made in winter wheat agrocoenosis – 72.6–100 %, against cereal aphids – 79,6–100 %, keeping by this 1.5–6.9 % of grain yield. During the growing seasons 2017–2019 the combined insecticides have shown high efficiency in reducing cereal leaf beetle larvae number in winter triticale crops for 89,0–99,0 %, winter barley – 89,6–97,5 %, spring wheat – 83,3–100 %, the kept grain yield has made 1,6–8,1 %.

The article presents a retrospective analysis of the biological effectiveness of insectoacaricides widely used in granaries - Actellik, EC (pirimifos-methyl, 500 g/l) and Prostor, EC (bifenthrin, 20 g/l + malathion, 400 g/l) to protect agricultural products at storage. For the first time, a decrease in the effectiveness of preparations containing pirimiphos-methyl against grain beetle (Rhyzoperta dominica F.) and mites (Acarina), a composition of malathion and bifenthrin against rice weevil (Sitophilus oryzae L.), brachycerous cucuid beetle (Cryptolestes ferrugineus Steph.) and mites (Acarina) is determined. In order to expand the assortment, the biological effectiveness of the insectoacaricide Pirinex Super, EC (chlorpyrifos, 400 g/l + bifenthrin, 20 g/l) has been studied. Further monitoring of the state of stock pest populations and the search for new insectoacaricides for use in technocenoses of granaries is indicated.

The article presents the results of monitoring the imago of the European corn borer using a mixture of phenyl acetaldehyde and 4-methoxyphenyl alcohol as an attractant, container and barrier – type traps in 2018–2019. It is determined that container-type traps are the most promising for monitoring the pest imago. Based on the calculated statistical models, taking into account the number of adults caught by them, it is possible to predict the number of ovipositions and damage to corn plants.

It is determined that during the years of mass sucking pests development (2019 - 2020) in the industrial type orchards of Belarus, the shoot damage by apple leaf gall midge (Dasyneura mali Kieff.) has made 42.7 %, the number of red fruit mite (Metatetranychus ulmi Koch.) has reached 10.3 individuals per leaf. The effectiveness of three-fold two-component insecticides application against apple gall midge, during the most vulnerable for the phytophage development periods, by harmfulness decrease during the vegetation period has made 83.4 - 86.4 %, and by wintering larvae number has reached 77.9 %. The double use of preparations against red fruit mite ensures the effectiveness of protective measures to reduce the number of pests during the growing season at the level of 80 - 90 % and 70 % by hibernating eggs number.

The article presents the results of studying the influence of black root of sugar beet incidence on sugar beet productivity depending on the degree of crop rotation saturation with sugar beet, the precursor, the main soil tillage and new fungicidal protectants. It has been determined that the effective black root of sugar beet control is possible only with a combination of agrotechnical and chemical measures. The most effective agronomic methods for reducing the development of black root of sugar beet and providing the maximum productivity of sugar beet are: saturation of crop rotation with sugar beet for not more than 20 %, the use of crop rotation link “pea – winter wheat – sugar beet” and double disking at a depth of 10 cm as primary tillage. Also, to control black root of sugar beet, the fungicidal protectant Maxim XL, SC at the rate of 7-9 l/ha is recommended.

The article presents the results of studying the red spider mite (Tetranychus urticae Koch) harmfulness in soybean crops. The optimum time and expediency of using the preparations have been substantiated. For the first time, the relative coefficients have been calculated and harmfulness quantitative assessment has been given. The effectiveness of Apollo acaricide, SC (clofentezine, 500 g/l), insectoacaricide Voliam Targo, SC (abamectin, 18 g/l + chloranthraniliprol, 45 g/l), Karate Zeon insecticide, MC (lamda-cyhalothrin, 50 g/l ) in decreasing the pest number has been studied. The economic thresholds on the expediency of preparations application have been developed, taking into account their cost, as well as varietal and zonal specificity for protecting soybeans against red spider mite.

The article presents the results of evaluating the antagonistic effect of the fungus Trichoderma asperellum D-11, the basis of the biological preparation Fungilex, L, in relation to the Botrytis cinerea Pers., isolated from the phytopathological material of tomato plants in the greenhouses of Belarus. It is found that the fungus Trichoderma asperellum D-11 has a high complex antagonistic activity, inhibiting the pathogen growth for 52,8–96,0 % and exhibiting hyperparasitic properties. The biological effectiveness of Fungilex, L for gray mould control under on-the-farm conditions has made 94,1 % by the end of the growing season. The studies can justify the inclusion of the biopreparation in the system of measures to activate the anti-resistant component of the technology for protecting tomato against gray mould.

The article presents the results of efficiency evaluating of microbiological growth regulator «MaxImmun» on the base of the elicitor components – inactivated bacteria Pseudomonas chlororaphis subsp. aurantiaca 162 and Bacillus subtilis 494 and their secondary metabolites – when growing onion in oneyear culture. It is shown that the use of the preparation provides the productivity increase for 29,0–55,0 %. The protective effect of the preparation against downy mildew (peronosporosis) has been noted: the biological effectiveness for crop protection against the disease has reached 71.4 %. Based on the studies, the preparation MaxImmun» is recommended for use in the Republic of Belarus as a plant growth regulator in the agricultural sector and in private farms.

The improved two-stage and preparative “one-pot” methods for the synthesis of 2,5-diphenylthiophene and its methoxy and bromo derivatives from the corresponding terminal arylacetylenes have been realized. Taking into account the conditions and principles of “green” chemistry, the syntheses are implemented with such important criteria as saving of atoms, availability and low cost of reagents. The resulting compounds can be used for the synthesis of biopesticide analogues.

The behavior of herbicide active ingredients used for vegetable peas protection against weeds in soddy-podzolic soil has been studied. It has been shown that the use of herbicides Corum, WSC (bentazone, 480 g / l + imazamox, 22.4 g / l) at a rate of 1.0-1.5 l/ha and Miura, EC (quizalofop-P-ethyl, 125 g / l) at a rate of 1.0 l/ ha does not pose a danger to subsequent crops of the crop rotation, since already 20- 40 days after their application, the active ingredients are localized in the arable layer and do not exceed the determined maximum permissible concentrations, and after 75 days they are exposed to complete decomposition.

The conditions of the modern intensive technology use require high yields of good quality corn. The main technique aimed at achieving this goal is the use of mineral and organic fertilizers. When planning yield, the state of soil fertility and the economic importance of cultivating crops must be taken into account. To form high yields, corn plants require significant amounts of nutrients throughout the growing season. Therefore, the relevance of research aimed at studying the effect of fertilizers on the yield and quality of corn is undeniable.
In the conducted studies, fertilizer systems have been determined providing corn grain yield increase, improving the grain chemical composition and quality. It is determined that the highest grain yield (103,8 cwt/ha) and crude protein content (10,40 %) have been in the variant with an organic-mineral fertilizer system of 60 t/ha of manure combined with MicroStim – Zn foliar top dressing against the background of N₉₀P₇₀K₁₂₀ + N₃₀.

The possibilities of phenylcarbamate and phenylurea herbicides micro quantities determination with the gas-liquid chromatography method have been studied. By the example of phenmedipham, desmedipham, isoproturon and chlorotoluron, the possibility of direct determination of the analyzed compounds without preliminary hydrolysis of substances, significantly increasing the expressiveness, selectivity and sensitivity of determination is shown.

The results of residues determination of herbicides isoproturon and diflufenican in plant products (winter and spring wheat, spring barley, winter rye) are presented. It is shown that isoproturon and diflufenican residues have not been detected in grain and straw yield, and in a single case have been found in winter wheat green mass at the amount of 0.013 and 0.008 mg/kg.

The results of determining the residues of insecticides based on lambda-cyhalothrin in 2018-2019 in grain and straw of winter and spring wheat, spring barley, green mass and corn grain, sugar beet roots, apple fruits using a gas chromatograph are presented. It is shown that residues of the active ingredient lambda-cyhalothrin have not been detected in sugar beet roots, apple fruits, green mass and corn grain, winter wheat grain, grain and straw of spring barley, but have been found in winter and spring wheat straw at the amount of 0 , 21 and 0.039 mg / kg. The analysis of the obtained differences has been done.

The results of acetamiprid - containing insecticides residues determination during 2018–2019 in the plant production (corn, potato, sugar beet, spring wheat, spring barley, winter rape, spring rape) are presented. It is shown that acetamiprid residues have not been detected in green mass, grain, oil, straw, tubers, roots yield.