Weeds as a supplementary or alternative food for Arion lusitanicus Mabille (Gastropoda: Stylommatophora)

Susceptibility of 30 weed species to A. lusitanicus feeding was evaluated under natural conditions two successive vegetation seasons (1997–1998). Observations were conducted on the number and degree cf plant in]uries, and as a result 13 weed species were found to be most frequently and most heavily injured. Food preference of slugs for 10 selected weed species and 8 cultivated plant species was determined under laboratory conditions. It was found that the most frequently and most seriously damaged under field conditions was Aegopodium podagraria L. – this and other weeds can be an alternative food for the slug. A comparison of the number of seedlings of the studied species eaten showed a high susceptibility of Galinsoga parviflora Cay., Brassica napus L. and Helianthus annuus L. to slug feeding.