Selective herbicides to control Sosnowsky’s hogweed (Heracleum sosnowskyi Manden.) in pine and spruce plantations

Abstract

In recent years, in the European part of Russia, massive and extremely negative distribution of Sosnovsky’s hogweed (Heracleum sosnowskyi Manden.) on various land categories has been observed. On the lands of the forest fund, there is also a threat of a rapid spread of hogweed, mainly in low-density stands, open spaces, forest plantations, and in fresh clearings. As a result, the growth of woody plants, first of all conifers, is suppressed, their death is observed, and environmental, aesthetic and industrial damage increases. Mechanical measures to combat hogweed are not effective enough and are very laborious. The article presents the results of a field experiment carried out in the Leningrad region in 2019–2020. The aim of the study was to assess the effectiveness of herbicides towards Sosnovsky’s hogweed and accompanying herbaceous species, as well as to evaluate their selectivity towards seedlings of Scots pine (Pinus sylvestris L.) and spruce (Picea abies (L.) Karst.). The herbicides studied were Anchor-85, Mortyra, Deimos, Lontrel-300 and Magnum in various combinations and application rates. The herbicides Anchor-85, Mortyra and Magnum showed high efficiency in suppressing Sosnovsky’s hogweed, however, only Anchor-85 and Mortyra turned out to be selective enough in relation to conifers.