INVESTIGATION OF THE LUSITANIAN SLUG (ARION LUSITANICUS MABILLE) DAMAGE

Abstract

The Lusitanian slugs (Arion lusitanicus Mabille) is one of the species of invasive animals originated from Spain and Portugal, Lusitania region in particular. The slugs were first detected in 2008 in Kaunas, Lithuania. The spread of this species is rapidly increasing, which creates unfavourable conditions for growing plants in gardens, orchards, and other areas. The study was carried out in the orchard of Vytautas Magnus University Botanical Garden by controlling their damage by applying mulch of buckwheat husks. The aim of the research was to identify the effectiveness of buckwheat husks as a natural plant waste in protecting garden plants from damage caused by the Lusitanian slugs. In 2021, the study was carried out in the training garden, the collection department of VMU Botanical Garden. The benefits of mulching lettuce with buckwheat husks to protect them from invasive slug damage have been analysed. The lettuce examined were grown in 1.2 m width beds, where the gaps between vegetable beds were surrounded by a well-maintained lawn. There were four replicates of the study, when the area of 1 m2 was investigated. At the investigated sites, plants were mulched with a dry, loose, and clean buckwheat husk layer of 5 cm thickness. The damage caused by the Lusitanian slugs was recorded by measuring damage on plant leaves and converting the damage into the percentage expression. The phytofixation method was used. Damage was assessed on a five-point scale, where 0 points - plants undamaged, 1 point - damaged up to 15%, 2 points - damaged from 15 to 30 per cent 3 points - damaged from 30 to 50 per cent, 4 points - damaged from 50 to 75 per cent, 5 points - damaged (destroyed) from 75 to 100 per cent of leaves of the investigated plants. The results of the research showed that the use of special partitions made from buckwheat husks and mulching of vegetables can control the damage of invasive slugs. Minor damage was found in vegetables mulched with buckwheat husks: damage from 1 to 2 points. In the control site, where the plants were not mulched with buckwheat husks, the damage was 3 points. Having assessed the damage, it can be stated that the activity of Lusitanian slugs was affected by less favourable environmental conditions: sunny days, high ambient air temperature, limited level of precipitation and a wellmaintained environment, as there were no shady places and high grasslands or other common shelters for slugs.