Patogenicidade de Bacillus thuringiensis para Alphitobius diaperinus Panzer 1797 (Coleoptera: Tenebrionidae) em condições de laboratório e semi-campo

• Ano de defesa: 2019
• Autor(a) principal: Maciel, Rodrigo Mendes Antunes
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Tecnológica Federal do Paraná; Dois Vizinhos; Brasil; Programa de Pós-Graduação em Zootecnia; UTFPR
• Palavras-chave em Português: Pragas - Controle biológico; Aviários; Entomologia; Pests - Biological control; Aviaries; Entomology; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOSSANIDADE::ENTOMOLOGIA AGRICOLA; Produção Animal
• Link de acesso: http://repositorio.utfpr.edu.br/jspui/handle/1/4095

Alphitobius diaperinus is the main pest of cut aviaries worldwide and its control is carried out, predominantly with synthetic chemical insecticides, which are harmful to birds and the environment, in addition to the low control efficiency, being the only available one. Biological control with Bacillus thuringiensis may be a viable, toxicological and ecotoxicologically safer alternative for the control of A. diaperinus. Thus, the objective of this work was to evaluate the pathogenicity of B. thuringiensis strains on larvae and adults of A. diaperinus under laboratory and semi-field conditions and to determine the genetic profile of B. thuringiensis strains. In the in vitro evaluation, the strains Br 12, Br 58, Br 67, Br 80, Br 137 and Br 138 were used at 3x108 UFC / mL-1 (treatments), in two bioassays (larvae and adults). To do this, 10 mL of each treatment were mixed in 20g of chicken feed and partitioned into eight 12-well plates (replicates), with each well receiving a fourth-instar larvae. In the adult bioassay the replicates consisted of Petri dishes with 12 insects each, totaling 96 insects per treatment in each bioassay. The plates were conditioned in an air-conditioned room and the number of dead insects quantified over 10 days. For the semi-field bioassay, the same strains were used, except Br 80 and Br 138. A mixture of poultry litter and chicken ration was prepared in plastic boxes - experimental units (UE), which received 40 insects (20 instar larvae and 20 adults) each and then sprayed 3 ml of each treatment on the bed. The EU was allocated in an air-conditioned environment and the evaluation took place on the 7th and 10th days, quantifying the dead insects. The strains were submitted to PCR and subsequent run of Electrophoresis in agarose gel to determine the genetic profile. In the in vitro tests the Br 12, Br 58, Br 67 and Br 137 lines caused accumulated mortality for A. diaperinus larvae, 65.6%, 66.6%, 66.6% and 69.7%, respectively, differing significantly from the control (26.0%). In the evaluation over time the mortality caused by the strains was significant only in the period of 96-144 hours, Br 67 (32.2%) and Br 80 (30.2%), and in the period of 168-216 hours the lineage Br 137 (31.2%). In the adult bioassay of A. diaperinus, only the Br 58 strain caused significant accumulated mortality (35, 4%), which was not verified in the evaluations over time in any of the treatments. In the semi-field bioassay none of the tested strains caused significant mortality for larvae or adults of A. diaperinus. Regarding the genetic profile, coding genes for the Cry4 and Cry10 toxins were found, characterizing the strains as subspecies israelensis. The strains of B. thuringiensis subspecies israelensis are pathogenic to larvae of A. diaperinus under laboratory conditions. For the use of B. thuringiensis in the field, studies are needed to develop strategies of insertion in the management of the populations of this species.