Use of the neotropical fish Cnesterodom decemmaculatus for long-term control of Culex pipiens L. in Argentina

TRANCHIDA, M. C.; PELIZZA, S. A.; BISARO, V.; BELTRÁN, C.; GARCÍA , J. J; MICIELI, M. V

BIOLOGICAL CONTROL

ACADEMIC PRESS INC ELSEVIER SCIENCE

Año: 2010 vol. 53 p. 183 - 187

1049-9644

We released the native mosquito fish Cnesterodom decemmaculatus into suburban drainage ditches in order to evaluate its potential as a long-acting agent for the control of Culex pipiens larvae in natural breeding sites. The inoculation of predator fish was conducted in 9 ditches at three densities: 1, 7, and 13 fish/m2. The experiment was conducted during a period of 2 years (2006—2008). The number of immature stages of Cx. pipiens was recorded before and after release. On a monthly basis, the digestive-tract contents of some fish and the average number of offspring from the females was recorded. A bioassay was performed to evaluate if the Cx. pipiens females were able to choose oviposition sites with respect to the presence or absence of predators. Fifteen weeks after release, a 99% reduction in the number of immature stages was registered in the drainage ditches containing 13 fish/m2, while at 22 weeks, a value of 99% was also observed in those with 7 fish/m2. The ditches with 1 fish/m2 evinced reductions in the density of immature stages relative to the controls, but over the entire experiment these diminutions did not prove statistically significant. The number of offspring registered per adult C. decemmaculatus female ranged from 4 ± 1.41 (mean ± SD) to 7.4 ± 0.89. Larval remains were detected in the fish collected in January, February, March, June, and September of 2006. Cx. pipiens adult females preferred those containers where the predators were absent for oviposition sites.