Potencial de nematóides entomopatogênicos (Rhabditida: Steinernematidae e Heterorhabditidae) para o controle de Diabrotica speciosa Germar, 1824 (Coleoptera: Chrysomelidae)

• Ano de defesa: 2009
• Autor(a) principal: Santos, Viviane
• Orientador(a): Moino Junior, Alcides
• Banca de defesa: Leite, Luís Garrigós, Carvalho, Vanessa Andaló Mendes de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: UNIVERSIDADE FEDERAL DE LAVRAS
• Programa de Pós-Graduação: DEN - Programa de Pós-graduação
• País: BRASIL
• Palavras-chave em Português: Vaquinha; Virulência; Steinernema; Heterorhabditis; Larva
• Área do conhecimento CNPq: CNPQ_NÃO_INFORMADO
• Link de acesso: https://repositorio.ufla.br/handle/1/2743

Entomopathogenic nematodes (EPN) are used in the biological control of soil insects, being promising for D. speciosa control. Considering that, the objectives of this work were to evaluate the virulence of different EPN on D. speciosa larvae, verify its action on eggs, larvae of third instar and pupae of D. speciosa in different concentrations, verify the influence of the temperature on larvae mortality, as well as the action of EPN on larvae when in greenhouse condition. The virulence of seventeen EPN strains was evaluated on larvae. The bioassay was composed of five replicates each one composed of ten larvae and 1 mL of suspension with concentration of 1500 infective juveniles (IJ)/replicate. Two selected strains were tested on eggs and larvae. The bioassay with eggs consisted of five replicates, each one containing ten eggs and 0.3 mL of suspension with concentrations of 25, 50, 100, 150, 200 and 250 IJ/insect. The bioassay with larvae consisted of five replicates, each one containing ten larvae and 1 mL of suspension with concentrations of 50, 100, 150, 200, 250 and 300 IJ/insect. One strain was selected and tested on pupae. The bioassay consisted of four replicates, each one with eight pupae and 1 mL of suspension with concentrations of 100, 150, 200, 250 and 300 IJ/insect. The evaluations were made after three days. Both selected strains were tested on larvae in temperatures of 15, 20, 22, 25 and 28º C. The bioassays consisted of five replicates, each one with eight larvae and 1 mL of suspension containing 200 IJ/insect. The susceptibility of larvae to one strain of EPN was evaluated in greenhouse. The bioassay consisted of six replicates with twenty larvae each and 50 mL of suspension with concentrations of 6,500, 13,000, 26,000 and 52,000 IJ/replicate. It was verified that all EPN caused larval mortality. The most virulent were Heterorhabditis sp. RSC01 (94%), Steinernema glaseri(84%), Heterorhabditis sp. JPM04 (82%) and Heterorhabditis sp. RSC05 (78%). There was no effect of Heterorhabditis sp. RSC01 and S. glaseri on eggs. Larval mortality caused by Heterorhabditis sp. RSC01 and S. glaseri was increased until the concentration of 200 IJ/insect. Heterorhabditis sp. RSC01 strain caused pupae mortality higher than 80% with concentration of 250 IJ/insect. The virulence of Heterorhabditis sp. RSC01 and S. glaseri was directly proportional to the increase of temperature. Heterorhabditis sp. RSC01 caused reduction in larvae survival in greenhouse conditions.