Pilot trials on St. Eustatius to contain the spread of and eradicate the invasive Giant African Land Snail
In 2013, the invasive Giant African Land Snail, Achatina fulica was found in a small part of urban St. Eustatius. In collaboration with local government agencies and Dutch universities we conducted field and laboratory pilot trials of control methods from October 2015 to June 2016. From the initial two gardens in 2013, the species has since been confirmed in 37 gardens encompassing an epicentre of about 100 lots in the Bay Brow area. During the study period, application of eco-friendly iron-phosphate snail bait successfully prevented further spread into adjacent buffer-zone monitoring areas. Iron-phosphate snail bait was effective in greatly reducing snail population density. It was applied once a week at an average density of 0.7 g/m2 at garden level, but was concentrated in hotspot snail habitat areas. Nevertheless, hand picking, which is more labour intensive and gives more variable results, also appeared effective in reducing snail density. Finally, beached Sargassum seaweed, brought forth as a snail deterrent used on neighbouring islands, did not measurably kill snails above zero control levels, and we conclude that seaweed is unlikely to be effective in snail control.