The effect of herbicide Flex, AS (active ingredient fomesafen 250 g/l) on annual weed species common in soybean crops was studied. The studies were conducted under greenhouse conditions in 2019-2021. The sensitivity of ragweed Ambrosia artemisiifolia L., Asian copper leaf Acalypha australis L., common lamb's quarters Chenopodium album L., common dayflower Commelina communis L., China jute Abutilon theophrasti Medik, trailing hollyhock Hibiscus trionum L., St.-Paul’swort Sigesbeckia pubescens Makino, green amaranth Amaranthus retroflexus L., elsholtzia Elsholtzia pseudocristata Levl. et Vaniot, and Siberian cocklebur Xanthium sibiricum Patrin ex Widd was determined. Weed treatment with Flex at rates of 0.75, 1.0, 1.25 and 1.5 l/ha was carried out three times a season at different stages of plant growth and development. The level of sensitivity of weed species to herbicide was judged by the decrease in height and weight of the aboveground organs of the experimental plants compared to the control. It was found that Flex herbicide completely destroys plants of all tested species in the early stages of growth and development (1-4 true leaves). When treating weeds that have formed 3-10 leaves, ragweed, green amaranth, Asian copper leaf, trailing hollyhock and Siberian cocklebur remain highly sensitive to the drug action (reduction of the aboveground weight up to 94-100%). Application of Flex on overgrown plants leads to a significant decrease in its activity against all studied weed species. When used in the third term, the herbicide is effective only on the green amaranth, suppressing the mass of the plants by 76-86%.

The work presents the results of testing tank mixtures of herbicides Proponit and Pledge applied in different doses to soybean crops during preemergence Treatment. The tests were carried out in Primorsky territory by standard methods in the form of the plot experiment in the trial field with brown meadow podzolized soils (by mechanical composition characterized as medium clay, content of humus 3.8%, labile phosphorus and exchange potassium in the soil 16 and 120 mg/kg respectively, PH 5.3). Hydrothermal conditions during the experiment were favorable for the implementation of the herbicidal potential of soil preparations. Trial tank mixtures showed high herbicidal activity against annual grass weeds (Echinochloa crusgalli, Setaria spp), annual dicotyledonous species (Ambrosia artemisiifolia, Acalypha australis, Abutilon theophrasti, Elsholtzia pseudocristata, Chenopodium album), Commelina communis and certain perennial dicotyledonous weeds. The use of mixtures of Proponit and Pledge in higher doses contributed to an increase in protective action and increase in the total herbicidal activity of preparations. The highest yield of soybean in the experiment, 2.41 t/ha, which exceeded the control value by 3.5 times, was achieved in the variant of the soil treatment with a mixture of herbicides in the maximum recommended rates (Proponit 3.0 l/ ha + Pledge 0.12 kg/ha). The economic efficiency of chemical weeding amounted to 39.0 thousand rubles/ha. Thus, in the conditions of soya crops contamination mainly by sensitive annual weed species and with optimal soil moisture, preemergence use of Proponit + Pledge tank mixtures was sufficient for reliable protection of soybean crops and eliminated the need for foliar herbicides.

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В Дальневосточном НИИ защиты растений в условиях деляночного эксперимента изучена биологическая и хозяйственная эффективность нового гербицида Флекс в посевах сои сорта Асука. Гербицид применялся при достижении культурой фазы развития два тройчатых листа. Исследования проведены в 2019 г. по общепринятым методикам на лугово-бурых оподзоленных почвах, типичных для Приморского края. Установлена одинаково высокая эффективность последовательного внесения препарата Флекс 1,5 л/га с ПАВ Тренд 90 0,2 л/га и граминицидов Фюзилад Форте 1,5 л/га и Центурион 0,3 л/га в смеси с Амиго Стар 0,6 л/га в отношении комплекса однолетних двудольных и злаковых сорняков в течение всего периода вегетации сои. Снижение общей биомассы сорных растений в этих вариантах опыта составило 97–99 %. Высокую чувствительность к гербициду Флекс (снижение массы на 99–100 %) проявила амброзия полыннолистная, занимающая лидирующее положение среди однолетних широколистных сорняков по частоте встречаемости и плотности произрастания в регионе. Новый препарат эффективно подавлял также жерушник болотный, марь белую и акалифу южную. Наложение граминицидов Фюзилад Форте и Центурион в смеси с Амиго Стар через 3 сут после обработки посевов сои препаратом Флекс способствовало эффективному контролю однолетних злаковых сорных растений: ежовника обыкновенного, видов щетинника и шерстняка мохнатого (снижение массы на 75–100 %). Токсическое действие препарата Флекс на двудольные многолетние виды сорняков проявлялось главным образом в торможении нарастания надземной растительной массы, которая в опытных вариантах при первом после обработки учете была ниже контроля на 55–88 %. К моменту уборки сои действие гербицидов на эту группу сорняков ослабло, в основном за счет наращивания массы щавельником курчавым. Высокая биологическая активность нового гербицида и граминицидов обеспечила сохранение значительной части урожая. В опытных вариантах урожайность сои выросла на 0,41–0,44 т/га и достигла 1,28–1,31 т/га в сравнении с контролем (0,87 т/га). Экономическая эффективность применения гербицида Флекс с последующим наложением граминицидов составила 3,64–3,96 тыс. руб./га. In the Far-Eastern Scientific Research Institute of Plant Protection in plot experiment studied the biological and economic efficiency of new herbicide Flex in crops of soybean varieties Asuka when the culture development phase was two trifoliate leaf. The research was carried out in 2019 using generally accepted methods on meadow-brown podzol soils typical for the Primorsky territory. An equally high efficiency of sequential application of the Flex preparation 1.5 l/ha with surfactant Trend 90 0.2 l/ha and graminicides Fusilade Forte 1.5 l/ha and Centurion 0.3 l/ha in a mixture with Amigo Star 0.6 l/ha for a complex of annual dicotyledonous and cereal weeds during the entire growing season of soy was established. The decrease in the total biomass of weeds in these variants of the experiment was 97–99 %. High sensitivity to the Flex herbicide (weight reduction by 99–100 %) was shown by ragweed, which occupies a leading position among annual broad-leaved weeds in frequency of occurrence and density of growth in the region. The new product was also effective in suppressing marsh cress, common lambsquarter, and Asian copperleaf. The imposition of graminicides Fusilade Forte and Centurion with Amigo Star three days after treatment of soybean crops with Flex preparation contributed to the effective control of annual cereal weeds: cockspur grass, species of bristlegrass and hairy cupgrass (weight reduction by 75–100 %). The toxic effect of the Flex preparation on dicotyledonous perennial species was mainly manifested in inhibiting the growth of aboveground plant mass, which in the experimental versions was 55–88 % lower than the control one when taken into account for the first time after treatment. By harvesting soybeans, the herbicidal effect on this group of weeds was weakened, mainly due to the mass build-up of curled dock. The high biological activity of the new herbicide and graminicides ensured the preservation of a significant part of the crop. In the experimental versions, the yield of soybean seeds increased by 0.41–0.44 t/ha compared to the control (0.87 t/ha). The economic efficiency of using the Flex herbicide with subsequent application of graminicides was 3.64–3.96 thousand rubles/ha.

The results of the study of the weed component of soybean, early grain crops and maize agrocenoses in Primorsky Territory are presented. In total, 111 species of weeds belonging to 35 families were found during the period from 2016 to 2020. Compared with the results of crop surveys conducted in 2006-2015, the total number of species detected has increased by 23. The largest number of species belongs to the families Asteraceae (24), Poaceae (15), Polygonaceae (11), Fabaceae (9), Brassicaceae (8), Caryophyllaceae (7) and Lamiaceae (5). The remaining 26 families were represented by 1-3 species each. For the first time weeds-representatives of the families Scrophulariaceae, Violaceae, Lythraceae, Onagraceae, Asclepiadaceae and Boraginaceae have been discovered. The floristic composition of soybean agrocenoses was the highest with 108 weed species from 31 families. In cereal and maize crops, weed diversity was less significant, with 75 species in 22 families and 72 species in 25 families, respectively. Weed vegetation in all the above crops is represented by 62 species of 19 families. The main weed species that grew on 97-99% of the surveyed territory with a sufficiently high average density of standing (21-61pcs/m2) were Asian copperleaf, cockspur grass and common ragweed. Also, more than half of the surveyed crops of soybeans, cereals and corn were hairy cupgrass, perennial sow thistle, common couch-grass, common lamb’s quarters, wormwood species, field horsetail, yellow thistle, dayflower and yellow foxtail. Practical measures to protect against weeds on the Primorsky Territory should be primarily aimed at controlling these species.