Progress 07/01/02 to 06/30/05
Outputs
The objectives of this study were to: test the mulluscicide activities of chemicals against the snail, Planorbella trivolvis; further evaluate those chemicals found to be the most efficacious in controlling snails in commercial ponds; establish a method to monitor the efficacy these treatments; and from this information design a pest management program to control snails in commercial catfish ponds. In a series of toxicity and efficacy studies nine chemicals were tested: potassium permanganate, formalin, endothal amine, diquat, sodium chloride rotenone, antimycin A, and liquid and crystal copper sulfate. Copper sulfate was found to be the most efficacious against P. trivolvis, with the least toxicity to catfish at .6mg/L Cu (2.35 mg/L copper sulfate). This treatment level was also efficacious against P. trivolvis eggs resulting in low hatching rates when compared to the negative controls 7 days post-exposure to the copper treatment (0-1% versus 36-55% hatching rate,
respectively). Studies evaluating the efficacy of copper sulfate at 2.5- 5.0 mg/L (2.5-5 ppm) in 0.25-10 acre ponds with alkalinities of 239 mg/L resulted in a 95% mortality of caged sentinel snails. As part of a field study two commercial catfish ponds with heavy snail infestations and high fish mortalities due to trematode infections were treated twice, at 6 day intervals, with 90.8 kg of copper sulfate with 11.35 kg citric acid in 113.6 L water at a rate of 37.9 L per 100 feet around the parameter of the entire pond. This treatment regime resulted in a reduction of the snail population by 78-95% 11 days post-treatment when compared to snail counts prior to treatment. In a final commercial field trial a 1.25 ppm application of copper sulfate resulted in a 95.4-97.7 % reduction in snails confined in cages at 7 sample sites in a 13.0 acre pond. In order to monitor the snail population year round in commercial ponds, three snail counting techniques (total snail counts in vegetation;
PVC pipes or Plexiglas at two feet from the shore; 4 sites/pond) were compared in 4 commercial catfish ponds monthly, for 2 years. Comparing snail counts using these three collection methods resulted in the detection of snails 77% of the time in the vegetation, 58% of the time with the PVC pipes and 35% of the time with the Plexiglas. Although the most sensitive indicator of the presence of snails was the vegetation, this method was extremely labor intensive. When both the vegetation and PVC method were combined, snails were detected 95.6% of the time. Final recommendation: Copper sulfate treatments of 0.75-1.25 ppm (2.5-5.0 ppm CuSO4 *5 H20) were effective in killing snails around pond margins with minimal risk to fish when applied at 20-24 degrees C. This recommendation will have to be tailored to individual farms/ponds. Caution should be used when the health status of the fish is in question or high pond temperatures, low alkalinities or bloom die-offs exist.
Impacts
This research indicated that copper sulfate when administered at .75-1.25 ppm (2.5-5 ppm CuSO4 *5 H20) around pond margins, was an efficacious method in controlling snail populations in commercial catfish ponds. The most efficacious method to monitor the snail populations was collecting snails from vegetation sites in conjunction with PVC pipes, which could detect the presence of snails 95.6% of the time. This research provides the necessary information catfish farmers need to implement an effective management scheme to control trematode infections in catfish by effectively controlling the snail populations (Planorbella trivolvis) in commercial ponds.
Publications
- Mische, C. M., D. J. Wise and L. M. Pote. 2005. Acute toxicity of chemicals to the marsh rams-horn snail Planorbella trivolvis. Journal of the World Aquaculture Society. 36: 560-563.
- Pote, L. M., M. C. Yost, C.M. Doffitt, B. S. Dorr, D. T. King, A. Camus and D. Wise. 2005. Further elucidation of the life cycle and pathology of the digenetic trematode, Bolbophorus damnificus. In proceedings of the 30th Annual Eastern Fish Health Workshop. June 13-17, Shepherdstown, West Virginia.
- Wise, D., C. Mische, T. Byars and A. Camus. 2005. Evaluation of copper sulfate to control snail numbers in catfish ponds affected by Bolbophorus trematodes. In proceedings of In proceedings of the 30th Annual Eastern Fish Health Workshop. June 13-17, Shepherdstown, West Virginia.
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Progress 01/01/04 to 12/30/04
Outputs
The objectives of this grant are to: evaluate the molluscicide activity of chemicals; develop a monitoring program to detect snails; and design a management program for snail control. Toxicity tests were performed on rams horn snails using the following chemicals: potassium permanganate (KMnO4, considered 100% active), formalin (37% formaldehyde solution, considered 100% active), Hydrothol 191 (53% Mono(N, N-dimethylalkylamine), Cerexagri, (King of Prussia, Pennsylvania), Diquat (36.4% diquat dibromide[6,7-dihydrodipyrido(1,2-a:2, 1-c) pyrazinediium dibromide) sodium chloride (NaCl, 100% active) rotenone (C23H22O6, 5% solution), Fintrol (23% Antimycin A, Aquabiotics Corp.), liquid copper sulfate (CuSO4*5H20, 5% metallic copper), and copper sulfate crystals (CuSO4*5H20). Of the chemicals tested in this study, only copper sulfate appeared to have potential to treat ponds for snails. The other chemicals tested were non-toxic to the snails. Alkalinity did not appear to
affect copper toxicity to snails, but toxicity increased with increasing temperatures. We also completed the snail monitoring program in 4 commercial catfish ponds. Using snail traps (30 total; 2 different models) in each pond, snails were checked monthly and the number, life stages, and snail species were recorded. In addition we compared snail populations in commercial ponds either treated with copper sulfate or untreated to determine the efficacy of treatment and duration of the treatment efficacy. Data are being analyzed.
Impacts
This research will test the efficacy of molluscicidal compounds approved for use in food fish ponds against all snail stages; establish a monitoring program for the detection of snails; and integrate this information into an economical, practical pest management program for the control of snails in commercial fish ponds. This research is vital to the catfish farmers. With the heavy fish losses this industry has suffered due to this trematode, they are willing to adopt any snail control program that is economical, and practical. Currently catfish farmers are treating ponds if any live snails are observed. In order to control the snail population, ponds are treated multiple times, which is expensive and time consuming. The treatment regime varies from farm to farm, often with inconsistent results. The results of this research will provide a pest management plan for snail control so that the farmer can make informed decisions about: which compounds are the most
efficacious and practical to use, the most effective method in which to use them, and the frequency required to be the most efficacious.
Publications
- No publications reported this period
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Progress 01/01/03 to 12/31/03
Outputs
Last year (2002) the molluscicide activity of Hydrothal, Reward, Formalin, copper sulfate, potassium permanganate, Fintrol, and hydrated lime was tested and a LD 50 was determined. The most efficacious and least toxic treatments were hydrated lime and copper sulfate. This year preliminary pilot treatments with these two compounds were done in experimental and field ponds to confirm methodology. Both treatments appeared to be effective molluscicide treatments in ponds. We also continued the snail monitoring program for another year in 4 commercial catfish ponds. Using snail traps (30 total; 2 different models) in each pond, snails were checked monthly and the number, life stages, and snail species were recorded. Data is being analyzed. We are now ready to confirm the efficacy of copper sulfate and lime against all snail stages in treated ponds and monitor the efficacy of these treatments with our snail traps.
Impacts
The results of this research will not only provide information to design a practical, economical pest management program for snail control in commercial catfish ponds, but can also serve as a model for snail control programs in other aquaculture systems.
Publications
- No publications reported this period
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Progress 01/01/02 to 12/31/02
Outputs
The objectives of this grant were to: evaluate the molluscicide activity of chemicals; develop a monitoring program to detect snails; and design a management program for snail control. The molluscicide activity of Hydrothal, Reward, Formalin, copper sulfate, potassium permanganate, Fintrol, and hydrated lime was tested and a LD 50 was determined. Snails were exposed to each chemical at increasing concentrations for 24 h, 30 min, and 10 min. The 10 and 30 min exposure times were used to simulate a pond margin treatment. Only copper sulfate and hydrated lime had any practical application, since the LD 50 of the other chemicals were greater than the LD 50 for catfish fingerlings. A snail-monitoring program has also been underway for a year in 4 commercial catfish ponds. Using snail traps (30 total; 2 different models) in each pond, snails have been checked monthly and the number, life stages, and snail species were recorded. Data is being analyzed. We are now ready to
confirm the efficacy of copper sulfate and lime against all snail stages. Pond studies will begin this year to confirm these results and snail viability/activity will be evaluated using techniques and information from the snail monitoring experiment.
Impacts
The results of this research will not only provide information to design a practical, economical pest management program for snail control in commercial catfish ponds, but can also serve as a model for snail control programs in other aquaculture systems.
Publications
- No publications reported this period
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