Mortality to the Giant African Snail,Lissachatina fulica(Gastropoda: Achatinidae), and Non-Target Snails using Select Molluscicides

Abstract

Laboratory bioassays and caged field trials were conducted to compare the acute toxicities of molluscicide formulations on the neonate, juvenile, and adult development stages of giant African snail (GAS) Lissachatina fulica (Bowdich 1822) and 3 non-target snail species in Barbados. Nine commercially available molluscicides, diatomaceous earth, and a kaolin clay product (Surround WP) were evaluated. High levels of mortality to neonate GAS were seen in all the laboratory molluscicide bioassays except for Surround and diatomaceous earth. The highest mortality rates to neonate GAS were observed from Durham granules and Slugfest treatments tested during field trials. Deadline, Durham granules, Metarex, and Orcal pellets caused the highest rates of mortality to juvenile GAS in our field trials. For adult GAS several molluscicides including Blitzem, Deadline, Durham Granules, Mesurol 75W, Metarex, Orcal pellet, and Slugfest caused greater than 95 % mortality in laboratory bioassays. Field trials showed that Durham granules and Slugfest yielded the highest mortality rates. Sluggo pellet, touted as an environmentally safe molluscicide, did not cause high rates of mortality to juvenile and adult GAS in our field trials, but did cause higher rates of mortality to neonate GAS than the control. The majority of the molluscicides tested in our trials were equally or more lethal to 3 non-target snail species than GAS. Our results identify several effective commercially available molluscicides that can be used to control incipient populations of GAS. However, our results show that the potential impact on non-target snail species during control or eradication programs may be considerable, causing substantial mortality regardless of what brand, active ingredient, or formulation is used.