Control of Heracleum Sosnowskyi Plant Numbers in Agricultural and Forestry Phytocenoses of Ukraine

Abstract

As of today, Heracleum Sosnowskyi have expanded from transformed habitats and small areas into natural conditions, where they occupy stable positions and is characterised by high phytocenotic activity, often being dominant or co-dominant. Considering that there are no clearly developed methods of control of this invasive species, there still is an urgent need to develop the methods of control of both annual and perennial plants under conditions of Ukraine. The aim of the study was to determine the effectiveness of different methods of control of Heracleum Sosnowskyi. A field experiment was carried out during 2015-2020 on typical medium loam black soil. Four experiments were conducted: 1 – mechanical measures; 2 – screening; 3 – hot steam; 4 – use of herbicides. A randomised experimental design with four repetitions was used. It was found that an effective approach is the removal of the weeds with the root to a depth of at least 10-15 cm. Complete shading of the plants to the stage of four leaves within 30 days ensured their complete disappearance. The rate of Heracleum Sosnowskyi plants mortality by hot steam ranged from 100% (cotyledon stage) to 85% (6 leaves stage). The most sensitive to herbicides were the shoots in the cotyledon stage, from 97.3% to 100%. The most susceptible to herbicides in the phase of cotyledon was from 97.3% to 100%. To the phase of 6 leaves sensitivity decreased from 43.2 to 60.7%. The most effective herbicides were: TaskExtra 66.5 WG (rimsulfuron – 23 g·kg-1, nicosulfuron – 92 g·kg-1, dicamba – 550 g·kg-1) + Trend-90 at a consumtpion rate of 385 g·ha-1 + 0.2 l·ha-1 and MaisTer Power OD (foramsulfuron, 31.5 g·l-1 + iodosulfuron, 1.0 g·l-1 + tincarbazone-methyl, 10 g·l-1 + cyprosulfamide (antidote), 15 g·l-1) at a consumption rate of 1.5 l·ha-1). Heracleum Sosnowskyi the following herbicides proved to be efficient: Elumis 105 OD, MD (mesotrion 75 g·l-1, nikosulfuron, 30 g·l-1) at a consumption rate of 2.0 l·ha-1 and the following tank compositions: Elumis 105 OD, MD + Roundup Max v.r. (glyphosate potassium salt, 551 g·l-1) at a consumption rate of 2.0 + 6.0 l·ha-1. In further study of this issue, it is advised to increase the efficiency of controlling the number of Heracleum Sosnowskyi plants and reducing the chemical effect on the environment