Slugs from the Nearctic: what we need to learn from the Western Palearctic

Abstract: The increase in slug biological control research over the last twenty-five years hasbeen prolific throughout much of the Western Palearctic region, leading to a literature repletewith examples of pest management recommendations. In contrast, the Nearctic region suffersfrom a limited knowledge of the ecology, biology, distribution, and impact of slugs throughoutthe entire ecozone, despite the area supporting a rich exotic fauna and several genera endemic tothe region. Consequently, management options are limited, new invasive species are oftenunreported, and agricultural productivity is regularly impacted due to limited control options andthe lack of robust guidelines for growers. This has been exacerbated by increases in global tradeand movement of produce and horticultural materials within North America, facilitating thedispersal of exotic molluscs to new areas. In this paper, we will provide a brief overview of thestatus of exotic and native molluscs in North America, paying particular attention to the diversityof crops throughout the Nearctic and identifying those areas with greatest probability forexperiencing slug damage at economically significant levels. Detailed information on the sourcelocation of exotic slugs invading the Nearctic from the western Palearctic is also presented usingArion subfuscus as a case study. To conclude, we refer to the literature from the WesternPalearctic to aide us in considering options for biological control and prioritizing malacophagousnatural enemies for future research efforts in the Nearctic.