Expediency and ways of perfection of system control by the productional process of grain-crops with the purpose of more effective grain production in Belarus are determined in the article basis the generalization own and other authors of scientific researches the results.

The article presents the results longstanding research of the effect of doses of mineral fertilizers on the growth and development of plants, the density of shoot formation, the yield of seeds and the structure of the Silfium рerfoliatum L. The high yield (293,8 and 301,7 kg/ha) of seeds was obtained at doses of N₆₀ and N₉₀ kg/ha with simultaneous application P₉₀ and K₁₂₀ kg/ha. It is better to use the vegetative method of reproduction when there is deficiency of seeds and the laying of plantations of seed crops takes place on low-cultivated lands. Planting of plants in parts of bushes and rhizomes ensures the production of seeds in the first year and high yields in the second and third years of plant life.

The results of studies of the effect of nano aqua citrate of microelements (Se + Ge) on the combined changes in the body of Aphidoletes aphidimyza Rond are made with the biologically active components. When supplemental nutrition is used, the optimum concentration nanoaquacitrate of microelements (Se – 0,0005 + Ge – 0,0003) – 0,0008 mg/dm³ with the biologically active components – 65 mg/dm³ the survival increases to 89 %, the fertility – to 98 %, reproductive capacity (Ρ_π) females – at 64,5 %. It is found that with the modification of trophics it is possible to improve the competitive ability of the aphidophagus, increase economic efficiency.

The results of studies on the productivity and nitrogen-fixing ability of leguminous vegetable crops (green beans, vegetable peas, vegetable beans, lens, fenugreek and blue fenugreek) on a sod-podzolic loamy soil are presented.

The amount of symbiotically fixed nitrogen in the phase of flowering of leguminous vegetable crops was from 26,9 to 52,7 kg/ha or 0,23–0,37 kg per 1 dt of green mass with a yield of green mass of 115,1–152,3 dt/ha and content of nitrogen of 1,85–2,21 %.

In the phase of full ripeness, symbiotic nitrogen fixation in the crops of lens was 2,2 kg/dt, vegetable peas – 2,4, green beans – 2,7, vegetable beans – 3,6, fenugreek – 4,0, blue fenugreek – 4,3 kg per 1 dt of seeds with a seed yield of 17,5 dt/ha (lens), 24,7 (vegetable peas), 35,7 (green beans), 74,5 (vegetable beans), 7,2 (fenugreek) and 3,8 dt/ha (blue fenugreek) respectively with a nitrogen content of 3,15–4,21 %

In cucumber plants under greenhouse conditions of Belarus downy mildew harmfulness is increased during winter-summer and summer–autumn crop rotations period. A high degree of the disease affection during 2016–2018 yr. is marked in hybrids Mamlyuk, Athlete and Kurazh. The results of wide-used one–component fungicide Topas, EC (penconazole, 100 g/l) and a new two–component preparation Cydeli Top 140, DK (difenoconazole, 125 g/l + cyphlufenamide, 15 g/l) in Athlete F1 plants by growing during winter-summer crop rotation against a natural infectious background under small– volume hydroponics conditions are presented. A high biological efficiency of Cydeli Top 140, DK is determined which has made after two times treatment by 0,1 % preparation solution 90,1 % under the moderate downy mildew development (2017 yr.) and 65,8 % under the epiphytoty disease development (2018 yr.). The maximum effect on downy mildew restriction with the preparation Topas, EC use by 0,075 % working solution concentration has been made in 2017 yr. and on the 14-th day after the last treatment has made 78,6 %, at that time under 2018 yr. conditions this indicator has not increased 24,0 %.

The biological and economic efficiency evaluation of her bicides based on pendimethalin in crops (plantings) of winter garlic, garden carrot and bulb onion has been done. It has been determined that their use after sowing and before crop emergence contributes to the number and the vegetative mass reduction of annual dicotyledonous and some cereal weeds, inhibits their germination within two months after spraying and has a positive effect on the formation of vegetable crops yield.

The species composition of ground beetles (Coleoptera: Carabidae) in the fields of spring rape in 2016 and 2017 is given in the article. In 2016, 43 species of ground beetles related to 13 genera were identified, in 2017, 15 ground beetles belonging to 7 genera were identified. Common views for 2016 and 2017 dominated by the species Pseudoophonus rufipes (De Geer, 1774).

A two-year research sandy loam soil the soil it is established that in maize with a predominance of annual dicotyledonous weeds, mainly Chenopodium album, the most effective use of Lumax, FE in a dose 3,5 l/ha the 3–5-leaf phase of a culture. Among the preparations containing sulfonylurea and used against perennial weeds, the highest net income is provided by relatively cheap Doublon, SC (1,0 l/ha) + Aegis, SC (0,2 l/ha) + Adyu surfactant (0,2 l/ha) or Doublon gold in a mixture with Ballerina and Adyu surfactant.

The surveys carried out on spruce trees in Kharkiv and Kharkiv region showed that the population of insects of genus Coccidae found on spruce trees was at the level 3 points. Three species of insects were identified, two of them - Physokermes hemicryphus and Physokermes inopinatus were firstly noted in the region. The optimum terms of chemical protection from insects of the genus Coccidae were established. All tested preparations showed high efficiency; the technical efficiency ranged within 90–96 %. Proteus and Movento preparations showed the greatest effectiveness in controlling these insects. The annual growth of spruce branches treated with insecticides was almost two times more than on the untreated trees.

The effectiveness of spring application (before soil treatment) of Tuviaan Fоrte as well as soil treatment in potato crops were studied in 2016–2018 in the conditions of Shamkir region of Azerbaijan. The most effective turned out to be Tavian Forte 2.0 l/ha + double cuitivation + hilling. The biological efficacу aqainst pests 93,5–97,6 % and the increase in the уield of potatoes was – 165 cent/ha.

The paper presents a method for determining the degree of inhibition of flax by calcium chlorosis by the ratio of the mass difference of 100 plants healthy and affected by calcium chlorosis, expressed in %. The degree of inhibition of flax by calcium chlorosis in the mass of 100 plants most fully characterizes the connection of this indicator with the yield losses of flax products.