Ecologia reprodutiva mediada por azadiractina no percevejo predator Blaptostethus pallescens

• Ano de defesa: 2014
• Autor(a) principal: Celestino, Daiane
• Orientador(a): Guedes, Raul Narciso Carvalho
• Banca de defesa: Campos, Mateus Ribeiro de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Entomologia
• Departamento: Ciência entomológica; Tecnologia entomológica
• País: BR
• Palavras-chave em Português: Pragas - controle; Azadiractina; Blaptostethus pallescens; Ecologia reprodutiva
• Palavras-chave em Inglês: Pests - Control; Azadirachtin; Blaptostethus pallescens; Reproductive ecology
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOSSANIDADE::ENTOMOLOGIA AGRICOLA
• Link de acesso: http://locus.ufv.br/handle/123456789/3984

Insecticide use is still the main method of arthropod pest management. Due to the social concern about environmental sustainability, new compounds have been used in an attempt to reduce the environmental impact of insecticides mainly regarding the risks to mammals, environmental persistence, pollution and development of insecticide resistance. Within this scenario new compounds and particularly bioinsecticides have been increasingly used. Several studies have been carried out to measure the efficacy of pest control agents and its effects on non-target organisms. However, beyond the investigation of the lethal effects of these compounds, the study of sublethal effects on natural enemies is also necessary and circumscribed to few species. Pirate bug predators (Heteroptera: Anthocoridae) play an important role as biological control of many insect pests, some which of great economic importance like the tomato leafminer Tuta absoluta. Blaptostethus pallescens Poppius (Anthocoridae) is a little-known species, but frequently found in tomato fields exposed to insecticides used for pest control, but little is known about those effects in this predator. This study assessed the lethal effects of three insecticides - chlorpyrifos, deltamethrin and azadirachtin - to B. pallescens using their field label rates. Azadirachtin was subsequently selected for assessment of its sublethal effects on behavior and reproduction due to tis lower acute mortality (< 25%) to predator adults after 48 hours of exposure. The insecticides chlorpyrifos and deltamethrin caused 100 % mortality within 4 hours, whereas the survival of insects exposed to azadirachtin was similar to the untreated control. Thus, further studies were conducted with azadirachtin to investigate its sublethal effects. Aiming to evaluate the effects of this insecticide in behavior, adult predators were placed in arenas treated with and without azadirachtin residues for the measurement of parameters such as number of stops, resting time, distance walked and walking velocity. There were no significant differences between treatments. Irritability and repellence to azadirachtin were assessed by the period and the proportion of individuals respectively remaining in the area containing insecticide residue on partially treated arenas. The results indicated that B. pallecens do not exhibit irritability nor repellence to azadirachtin. Subsequently predator couples were subjected to four treatments with azadirachtin untreated couple, treated female (and untreated male), treated male (and untreated female), and treated couple - where female longevity data, daily fecundity, fertility and F1 sex ratio were recorded. These data were used in a projection matrix that generated data of net reproductive rate, population growth rate and generation time for each treatment. The results indicated that there was difference between treatments. Thus, azadirachtin seems to be safer for the predator B. pallescens and therefore a good candidate for the use in pest management programs against T. absoluta.