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Braz. j. microbiol ; 42(4): 1445-1452, Oct.-Dec. 2011. graf, tab
Artigo em Inglês | LILACS | ID: lil-614609


The pigeon tick Argas reflexus is a pathogen-transmitting soft tick that typically feeds on pigeons, but can also attack humans causing local and systemic reactions. Chemical control is made difficult due to environmental contamination and resistance development. As a result, there is much interest in increasing the role of other strategies like biological control. In this study, the efficacy of three strains (V245, 685 and 715C) of entomopathogenic fungus Metarhizium anisopliae for biological control of three life stages of pigeon tick A. reflexus including eggs, larvae, engorged and unfed adults was investigated under laboratory conditions. Five concentrations of different strains of M. anisopliae ranging from 10³ to 10(7) conidia/ml were used. All fungal strains significantly decreased hatchability of A. reflexus eggs. Strain V245 was the most effective strain on the mortality of larval stage with nearly 100 percent mortality at the lowest concentration (10³ conidia/ml) at 10 days post-inoculation. The mortality rate of both engorged and unfed adult ticks were also increased significantly exposed to different conidial concentrations compared to the control groups (P < 0.05) making this fungus a potential biological control agent of pigeon tick reducing the use of chemical acaricides.

Animais , Argas/patogenicidade , Argasidae/patogenicidade , Columbidae , Entomophthora/isolamento & purificação , Fungos/patogenicidade , Controle Biológico de Vetores , Infestações por Carrapato , Métodos , Técnicas , Medicina Veterinária , Virulência
Rev. bras. parasitol. vet ; 19(3): 164-168, July-Sept. 2010. tab
Artigo em Inglês | LILACS | ID: lil-604662


The current study investigated the biology of nymphs of the first and second instars of Argas (Persicargas) miniatus. Nymphs were deprived of food for 15, 30 or 60 days and held at 27 ± 1 ºC and 80 ± 10 percent relative humidity (controlled conditions) or at room conditions of temperature and relative humidity. Nymphs of first instar deprived of food for 15 or 30 days molted to second and third instars in both controlled and room conditions. Nymphs of the first instar deprived of food for 60 days had 28 and 37 percent mortality in controlled and room conditions, respectively; and survivors did not attach to the host. Nymphs of the second instar, deprived of food for 60 days, molted either to the third instar or to males after feeding on Gallus gallus, and the nymphs of the third instar developed to adults (42.42 percent males and 36.36 percent females when nymphs were held in controlled temperature and humidity conditions, and 40.54 percent males and 48.65 percent females when nymphs were held in room conditions). The remainder of the nymphs molted to the fourth instar and then molted to females. In conclusion, the nymphal starvation period of 60 days determined the number of nymph instars in the life cycle of A. miniatus under the experimental conditions studied.

Os aspectos biológicos de ninfas de primeiro e segundo instares de Argas (Persicargas) miniatus quando submetidas a diferentes períodos de jejum (15, 30 e 60 dias), foram estudados em estufa climatizada (27 ± 1 ºC e 80 ± 10 por cento de umidade relativa) e em ambiente de laboratório. Ninfas de primeiro instar que foram submetidas a um período de jejum de 15 e 30 dias mudaram para ninfas de segundo e terceiro instar, em ambas as condições estudadas. No período de 60 dias de jejum verificou-se mortalidade de 28 e 37 por cento das ninfas de primeiro instar, em estufa climatizada e em ambiente de laboratório, respectivamente. As ninfas sobreviventes não se fixaram sobre os hospedeiros. As ninfas de segundo instar, após 60 dias de jejum, desenvolveram-se em ninfas de terceiro instar ou machos, quando alimentadas em Gallus gallus. Ainda neste grupo, as ninfas de terceiro instar mudaram para adultos (42,42 e 40,54 por cento machos; 36,36 e 48,65 por cento fêmeas, nas condições ambiente de laboratório e estufa climatizada, respectivamente) e o restante desenvolveu-se em ninfas de quarto instar que por sua vez mudaram para fêmeas. Então, a situação de jejum (60 dias) em que as ninfas foram submetidas determinou o número de ninfas no ciclo biológico de A. miniatus, sob as condições experimentais estudadas.

Animais , Feminino , Masculino , Argas/crescimento & desenvolvimento , Jejum , Ninfa/crescimento & desenvolvimento , Fatores Sexuais , Fatores de Tempo
Arq. bras. med. vet. zootec ; 55(4): 507-509, Aug. 2003. ilus
Artigo em Português | LILACS | ID: lil-349714


Eggs were obtained from female Argas (Persicargas) miniatus parasitizing chickens after natural ovoposition. The larvae from eggs were sacrificed, prepared for and mounted onto slides. Morphological and chaetotaxic studies enabled the following observation: idiosome and gnathosome shape; presence or absence of scutum, eyes and anal setae; number of palpi segments; number of files of teeth on the hypostoma; number of denticles on the apical crow; number of cheliceral digits; number of teeth in each hypostoma file; disposition and shape of opistosoma and podosoma setae in ventral and dorsal view. Based on these morphological features analyzed, it is concluded that the larvae of A. (P.) miniatus present variations in morphology and chaetotaxy that are useful to separate the larvae of the subgenus Persicargas.

Argas , Infestações por Carrapato