Two snail species, Planorbella trivolvis and Biomphalaria havanensis are common inhabitants of commercial catfish ponds and known to transmit the trematode Bolbophorus damnificus. Copper sulfate application is a promising management tool to control snails and thereby reduce trematode infestations.
We determined 24, 48 and 72-hr acute copper (Cu) toxicity to both species. Additionally, sequential low-dose treatments ranging from 0.1 to 0.8 mg/L Cu were evaluated on eggs, juveniles, and adults.
LC50 values were similar for both species of adult snails. Exposure times and LC50 values were: 24-h = 1.7 mg/L Cu; 48-h = 1.1 mg/L Cu; 72-h = 0.2 mg/L Cu. For multiple doses, four treatments of 0.4 mg/L Cu were enough to kill all snails of both species. Four doses of 0.1 mg/L Cu prevented all eggs from hatching in both species.
From this data, repeated doses of at least 0.1 mg/L Cu would be required for a strategy targeting eggs and juveniles. However, for strategies aiming to eliminate adult snails, four repeated doses of 0.2 mg/L Cu may be effective. Taken together, these data indicate repeated low-dose copper treatments can be effective for snail control in commercial catfish ponds.