Predador versus entomopatógeno: Podisus distinctus (Stal) (Heteroptera: Pentatomidae) desafiado por Beauveria bassiana e Metarhizium anisopliae

• Autor(a) principal: Poderoso, Júlio César Melo
• Data de Publicação: 2014
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/924
• topic: Podisus distinctus; Percevejo (Inseto); Fungos entomopatógenos; Podisus distinctus - Controle biológico; Distinctus Podisus; Bedbug (Insect); Entomopathogenic fungi; Podisus distinctus - Biological control; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOSSANIDADE::ENTOMOLOGIA AGRICOLA

Podisus distinctus (Stal) (Heteroptera: Pentatomidae) is one of the most important species of predatory bugs in the Pentatomidae family. This natural predator can be created in the laboratory and used for biological control of defoliating insects. The use of natural enemies is recommended, especially generalist insets such as Podisus distinctus. Entomopathogenic fungi, with about 90 genera and over 700 species described, are responsible for 80% of diseases in insects and are used for biological control of pests. The fungi were the first pathogens to be used for microbial control, but insects possess defense mechanisms against micro-organisms through their cellular immune system. There is little known about the dynamic response of the cellular immune system in predatory stinkbugs. The aim of this study was to evaluate the impact of entomopathogens on biological parameters of Podisus distinctus and characterize the cellular immune response against fungi Beauveria bassiana and Metarhizium anisopliae. The fungi were topically applied to the third instar nymphs of the predatory stinkbug with concentrations: 106, 107, and 108 conidia/mL of M. anisopliae and B. bassiana. The control was treated with sterile distilled water containing adhesive spreader Tween 80® / 0.01%. The parameters evaluated were the percentage of nymphal survival, duration of each stage, weight of females, and adult males originating from nymphs treated with fungal solutions. Couples were formed by concentration of fungal solutions B. bassiana and M. anisopliae. The parameters evaluated were pre-oviposition and oviposition, number of eggs, postures, nymphs per female, and longevity of adulthood for males and females. The immune response of the predatory stinkbug was studied in adults up to 48 hours old. These adults were treated topically with the deposition of a μL of the fungal suspensions in concentrations of 106, 107, and 108 conidia/mL; the control received a μL of spreader-sticker and distilled water. After 24, 48, 72, 96, and 120 hours of application the number of surviving P. distinctus males and females were evaluated. The hemocyte count of P. distinctus males and females were taken at each interval. The duration and survival of nymphs of the predatory stinkbug were negatively affected primarily by B. bassiana. The pre-oviposition period, number of eggs, and postures of nymphs were negatively affected after exposure to molds. The number of circulating hemocytes was lower in both genders after 24 hours of exposure to M. anisopliae. The survival of adult males and females of this predator stinkbug was lower in concentration of 108 conidia/mL of B. bassiana. Males and females of P. distinctus, after contact with B. bassiana, had fewer hemocytes. The negative influence of exposure to fungi B. bassiana and M. anisopliae indicates that although it is effective in controlling pests, these entomopathogenic fungi also negatively affect biological parameters of beneficial insects such as P. distinctus. Females and males of P. distinctus have an active immune system against the fungus M. anisopliae, but this was not enough to ensure their survival in the concentration of 108 conidia/mL of M. anisopliae and B. bassiana.