Designing a trapping strategy to aid Giant African Snail (Lissachatina fulica) eradication programs

In pest eradication programs, traps can directly reduce pest populations; however, their application to gastropod programs remains relatively unexplored. The South Florida Giant African Snail, Liassachatina fulica (Pulmonata: Achatinidae), eradication program allowed a realistic evaluation of their utility. Field studies were conducted to determine the best bait, barrier and trap for use during the eradication program. Immature and adult snails were attracted to banana fruit and a commercially produced bait but only the commercially produced bait did not attract non-target and pest mammals. Four commercially produced traps and 4 barriers were field evaluated for snail retention efficacy. Snails escaped all traps and trap/barrier combinations but the rate of escape ranged from 10-100% after 24 hrs. Laboratory studies confirmed that snails can survive crossing a 5 cm barrier of copper tape, salt, insect stickem or antifouling paint. In the laboratory study snails did not cross copper sulfate but they crossed the barrier in the field. Adding salt to traps as a means to retain snails reduced the number of snails trapped. Laboratory studies confirmed that dry salt decreased the number of snails entering traps and snails did not enter traps when the salt was dissolved in water. Two trap types and the commercial bait were selected for a large-scale program test. For three months, trapping along with hand collection and pesticide application were conducted on 114 properties in five locations. Traps caught snails when surveys and regular pesticide applications on the same properties did not detect them. On 21 occasions snails were only found in traps, and both immature and adult snails were caught. This study showed that traps could be effectively deployed in an eradication program and they could capture snails that may have escaped other control measures.