RESUMEN
Field trials of R. iyengari and R. culicivorax in the biological control for the mosquito larvae were conducted in Parkhar, Kuibyshevsk, Gissar districts and the outskirts of the city of Dushanbe, the Tadjik SSR. Larvae of Anopheles superpictus, An. pulcherrimus and An. hyrcanus in a dosage of 1-5 thousand intact larvae per sq. m were invaded by mermithids. The mean infection rate was 46 per cent. The maximum infection rate was 98 per cent. It depended on several factors: the dosage of intact larvae, temperature, water salinity, water flowage in the waterbodies and their overgrowth with plants. Slow-flowed rice paddies and flow-free fresh waterbodies turned to be the proper sites for mermithids. The effect was higher in Anopheles than in Culex mosquitos.
Asunto(s)
Mermithoidea , Control de Mosquitos/métodos , Animales , Anopheles/parasitología , Culex/parasitología , Ecología , Agua Dulce , Larva/parasitología , Mermithoidea/patogenicidad , TayikistánRESUMEN
Mermithid nematodes Romanomermis iyengari were released into 13 natural water bodies of various types at a ratio of 300-8000 invasive preparasites per 1 m2 of water surface in Tashkent region of Uzbekistan. Infected larvae of Anopheles martinius, An. hyrcanus, Culex modestus were found in 6 water bodies with low content of dissolved salts (Ca2+ + + Mg2(+)-3.8-6.7 mg equivalent/l, Cl(-)-38.3-160.2 mg/l). The infection rates of mosquito larvae were 9-67%. In laboratory tests mermithids infected up to 100% of mosquito larvae of the above-mentioned species as well as An. superpictus and Cx. pipiens from natural populations. Aedes caspius were resistant to mermithid infection. It is expected that in Tashkent region these mermithids can be used only in water bodies with low salt content.
Asunto(s)
Culicidae/parasitología , Mermithoidea , Control Biológico de Vectores/métodos , Animales , Ecología , Estudios de Evaluación como Asunto , Agua Dulce , Larva/parasitología , UzbekistánRESUMEN
Possibility of using Romanomermis culicivorax for mosquito control in the town of Voronezh and Moscow Province has been assessed. The infection rate of mosquito larvae didn't exceed 26% when preparasitic juveniles were released into water bodies at a ratio of 1-3 thousand per 1 m2 and temperature 18-25 degrees C. There were no evidences of mermithid settlement and hibernation in the water bodies of Voronezh. High efficacy of using R. culicivorax in mosquito larvae control can only be expected in these regions under hot summer conditions.
Asunto(s)
Culicidae/parasitología , Mermithoidea , Control Biológico de Vectores/métodos , Animales , Ecología , Agua Dulce , Larva/parasitología , Federación de Rusia , Temperatura , Factores de TiempoRESUMEN
The procedure of mass laboratory rearing of mermithid nematode Romanomermis culicivorax, a parasite of mosquito larvae, is described. Culex pipiens molestus larvae are used as a host for cultivation at the host: preparasites ratios of 1:4-1:6, enabling to obtain the greatest mass of nematodes (over 500 mg per 1 thousand of infested mosquito larvae) when the male female ratio in culture was 1:1. This rearing technique allows to obtain on average 350 thousand invasive mermithid preparasites per 1 g of adult mermithids. The above-proposed method is compared to the procedure rearing described earlier by Petersen, Willis (1972).