First release of the mermithid Strelkovimermis spiculatus in Culex pipiens mosquito populations in Argentina.

MUTTIS, E.; ACHINELLY, M. F; MICIELI, M. V

Mainz

Congreso; 47 th Annual Meeting of the Society for Invertebrate Pathology and International Congress of Invertebrate Pathology and Microbial Control; 2014

Society for Invertebrate Pathology

Mermithids have proved to be effective in parasitizing natural populations of mosquito larvae. However nothing is known about the inoculative introduction of this nematode in natural populations of culicids in our country. We report the results of the first field release of S. spiculatus in Argentine. Study area was constituted by house drainage ditches, breeding site of the mosquito Culex pipiens where this nematode was not present. The number and stage of mosquitoes were recorded pretreatment. Strelkovimermis spiculatus was introduced as second-stage juveniles (J2) obtained from laboratory cultures maintained at CEPAVE laboratory. Release was done in November 2012 (spring). A dose of 10,000 J2 per meter was applied (over a total area of 17 x 0.5 m). The number of J2 was based on previous results. Mosquito larvae were sampled 24 hs post-treatment once a week during a year, to corroborate the presence of nematode by microscopic dissection and emergence in fourth instars larvae. Parasitism by S. spiculatus began to be observed at thirst day post-application (3%). Values ranged between 0.01% and 86.3%. The highest value was recorded at 8 months post-release. This environment remained dry or without larvae during a period of four months. Nevertheless a parasitism of 45.2% was observed after this period during the first larvae collection and reaching levels between 4.8% and 86.3%. Only in three occasions was not observed infected larvae throughout the year of sampling. Strelkovimermis spiculatus was able to establish itself in this habitat and cause high levels of infection in Culex pipiens larvae.