[Application of a mermithid nematode for the control of mosquito larvae in natural conditions].

Field tests were carried out with the Romanomermis culicivorax nematode (Ross and Smith, 1976) for the control of 3 mosquito species--Anopheles albimanus (Wiedeman, 1821): Culex nigripalpus (Theobald, 1901); and Uranotaenia saphirina (Oster-Sacken, 1868)--in 10 natural reservoirs. The infective nematodes were disseminated in doses of 1 x 10(3) preparasites/m2 of surface area. Increased infestation indices were observed with values ranging from 1.2 to 3.4; mortality percentages fluctuated between 70 and 97% depending on the mosquito species found in the reservoirs. In those reservoirs containing specimens of the 3 species, anophelines showed more susceptibility to parasite infection; culicines showed a lower susceptibility in general. Mosquito larva populations were significantly reduced in the treated reservoirs.