Resposta de populações de Sitophilus zeamais à exposição dos óleos essenciais de cravo e de canela

• Ano de defesa: 2011
• Autor(a) principal: Correa, Yenis Del Carmen Gonzalez
• Orientador(a): Faroni, Lêda Rita D'antonino
• Banca de defesa: Pereira, Olinto Liparini
• 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: Coleoptera; Comportamento; Inseto; Toxicologia
• Palavras-chave em Inglês: Coleoptera, Behavior, Insect; Toxicology
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOSSANIDADE::ENTOMOLOGIA AGRICOLA
• Link de acesso: http://locus.ufv.br/handle/123456789/3937

The present study was designed to evaluate the toxicity, locomotory behavior, population growth rate and respiratory rate in adult insects of brazilian populations of Sitophilus zeamais subjected to exposure to the essential oils of cloves and cinnamon. The populations were collected in the cities of Guarapuava (PR), Guaxupé (MG), Coimbra (MG), Piracicaba (SP), and Cristalina (GO). The toxicity of the oils was tested at different concentrations (0.18, 0.35, 0.71, 1.41 and 2.12 μL cm-2) diluted in acetone (6:4 v/v). The experimental unit consisted of Petri dishes (6 x 1.2 cm) containing filter paper impregnated with essential oil. Twenty adults of Sitophilus zeamais were transferred to dishes, and mortality was assessed every three hours for 108 hours. Lethal concentrations LC50 and LC95, and lethal time LT50 were estimated for adults of Sitophilus zeamais using concentration- and time-mortality bioassays, and used to calculate the toxicity ratio (TR) of the oils for each population. The locomotory behavior of the insects was evaluated in two bioassays using arenas with surfaces completely and partially (half) treated with each of the essential oils. The concentrations used were 0.64 and 1.23 μL cm-2 for clove and cinnamon oils, respectively, which correspond to the LC95 for the most susceptible population (Guaxupé). Behavioral parameters measured were distance walked, walking speed, resting time, and number of stops. Additionally, we assessed population growth rates (ri), respiration rates (CO2 production) and body mass for the populations studied. It was observed that the LC95 for the essential oil of cloves varied from 1.23 to 6.84 μL cm-2, and the ascending order of susceptibility of the populations was Guaxupé, Cristalina, Coimbra, Piracicaba and Guarapuava. For cinnamon oil, LC95 values varied from 0.64 to 2.44 μL cm-2 for Guaxupé, Piracicaba, Coimbra, Cristalina and Guarapuava. LT50 values for the essential oils reduced as their concentration increased, and with the population of Piracicaba showing the highest LT50 values for both clove and cinnamon oils. Locomotory parameters (distance, speed and resting time) in the treated area varied with the oils and populations. However, insects from all populations showed irritability to the two oils, preferring to stay in the untreated surfaces. The toxicity of the essential oils affected the respiratory rate of the insects reducing the CO2 output, especially cinnamon oil. When maize grains were treated with the oils, some populations experienced higher reduction in the instantaneous growth rate than others in, but at concentrations above 2 μL/g in the grains, both oils led to zero population growth rates. Thus, with the results obtained in this study we can conclude that the essential oils of cloves and cinnamon have a significant effect on mortality by contact of and represent an alternative to using traditional insecticides.