Desenvolvimento de metarhizium anisopliae em ninfas de periplaneta americana durante a invasão

• Autor(a) principal: Machado, João Antônio Rangel
• Data de Publicação: 2015
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/4796
• topic: Metarhizium anisopliae; Ninfas; Periplaneta americana; Controle biológico; Metarhizium anisopliae; Nymphs; Periplaneta americana; Biological control; CIENCIAS BIOLOGICAS::PARASITOLOGIA

The susceptibility of cockroaches to infection with pathogenic fungi can be associated to the host species and their stage/instar. The high resistance of elder nymphs of Periplaneta americana, a synanthropic species in tropical and subtropical regions, against Metarhizium anisopliae is still poorly understood and can be connected to behavioral, physiological and mechanical mechanisms. Fourth and fifth instar nymphs (N4 or N5), treated topically with conidia, removed mechanically part of the conidia from the cuticle, antennae and legs, immediately after treatment and in the following days. A small number (< 5%) of the conidia on the cuticle germinated in the first 24 hours, and quantitative germination of the remaining conidia reached 80% within the next 7 days. In most of the treated nymphs, the fungus failed to reach the hemolymph during the 10 days of the test, and in the others, the number of hyphal bodies ranged from 500 to 8 x 107 per μL hemolymph. Few nymphs (30%) died within 10 days after inoculation, and M. anispoliae developed in 50% of the cadavers. The results confirmed the high resistance of elder P. americana nymphs to M. anisopliae and highlighted the importance of the early stages of the infection during the contact and insect invasion by the fungus. Subsocial behavior patterns and specific physiological factors in the cuticle, not elucidated in this study, are resistance key issues and need to be considered when developing mycoinsecticides for P. americana and other cockroach control.