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

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

Brasilia DF. Brasil

Simposio; X Simposio de Controle Biológico; 2007

EMBRAPA

In this study was determined the potential that have the neotropical larvivorous fish, Cnesterodom decemmaculatus for long-term control of Cx. pipiens immature stages in drainage ditches. Twelve ditches (average 25m long x 0.60m wide x 0,25m deep) from a suburban area of La Plata city, Argentina, were selected to evaluate C. decemmaculatus. Larvae density was monitored by weekly sampling (n=5) of natural populations of Cx. pipiens immature stages with a 300 ml dipper from January to October 2006. Cnesterodom decemmaculatus  was introduced in the ditches at doses of 10, 50, and 100 couples of adult fish (35±5mm long) per ditch (3 ditches per dose plus 3 controls). The mean larvae density in the 12 ditches before fish introduction was 430±51 (SD) larvae/dip. At week 10 post-introduction, Cx. pipiens larvae were eliminated from ditches with 100 couples of fish while 444±93 larvae/dip was recorded in control ditches. After 16 weeks, larvae were not recorded in ditches with 50 couples of fish while ditches with 10 couples and controls have similar mean larvae of 228±11 larvae/dip. Immature stages were not recorded  on cold weather months samples (June to September) in none of the ditches, meanwhile presence of fish during these months was confirmed in the 9 ditches where introduction was conducted.   Larvae were not recorded in ditches with 100 and 50 couple of C. decemmaculatus during October samples, while 70±9 and 272±101 larvae/dip were recorded in ditches where 10 fish couples were released and in control ditches, respectively.