Resumo

PEREZ-PACHECO, Rafael et al. Effectiveness and survival of Romanomermis culicivorax in natural breeding sites of mosquito larvae. Agrociencia [online]. 2009, vol.43, n.8, pp.861-868. ISSN 2521-9766.

Mosquitoes (Díptera: Culicidae) transmit causal agents of malaria, dengue and western Nile encephalitis, besides being extremely annoying for humans. The objective of this study was to determine the control effect of releasing 500 and 1000 Romanomermis culicivorax Ross and Smith nematodes per square meter into larval populations of Anopheles albimanus Wiedeman, Culex nigripalpus Theobald, and Uranotenia sapphiriuna Oster-Sacken in 13 natural breeding sites. The experimental design was completely randomized with a factorial arrangement of two factors (two dosages of nematodes and three species of mosquitoes). The doses of 500 nematodes m^-2 caused 74.3-87.8 % parasitism in larvae of the three species; the dose of 1000 nematodes m^-2 caused 77.2-96.9 % parasitism; that is, parasitism was higher with the higher dose of nematodes (p<0.001). With both doses the A albimanus larvae were significantly (p<0.001) more susceptible to parasitism by R. culicivorax (87.8-96.9 %) than those of C. nigripalpus (78-81.6 %) and U. sapphirina (74.3-77.2 %). The larval populations of A. albimanus, C. nigripalpus and U. sapphirina decreased 74 to 95 % 7 d after release of treatments. Moreover, R. culicivorax established and biologically recycled for at least three months. The infective capacity of R. culicivorax did not correlate significantly with physiochemical variables (pH, conductivity, oxygen, temperature, depth of breeding sites) or vegetation.

Palavras-chave : Biological control; mermithid; nematode.