ABSTRACT
New banana plant hybrids have been cultivated in the Brazilian fields, although there is no consistent information about the possible impacts on banana pests. The banana root weevil (Coleoptera: Curculionidae) is strongly drawn to the volatile rhizome of banana, and it is believed that its attractiveness for hybrid genotypes is different than that observed on banana plant varieties. This study aimed to evaluate the olfactory response of banana root weevil, Cosmopolites sordidus (Coleoptera: Curculionidae), to 20 banana genotypes in laboratory. According to the genetic and commercial similarity of plants, the genotypes were divided into four groups: 1) Cavendish; 2) Prata; 3) Maçã/Conquista, e 4) Ouro/Terra/Caipira/Figo. In the bioassay 1, the attractiveness of the banana root weevil was evaluated for genotypes of the same group. In bioassay 2, the pre-selected genotypes were compared among themselves. The study was replicated with insects and rhizomes in April (first season) and July (second season) of 2011 agricultural year. In the first season, the selected genotypes were Nanicão (AAA), FHIA 18 (AAAB), Princesa (AAAB), Ouro (AA), and Prata anã (AAB) (bioassay 1). In the second season, the selected genotypes were FHIA 17 (AAAA), PA 9401 (AAAB), and Thap Maeo (AAB), besides Nanicão and Ouro (bioassay 1). In both bioassays, the control was represented by absence of rizome. Overall, only Nanicão (AAA) and Ouro (AA) genotypes were more attractive than the control (in the first and second seasons, respectively) (bioassay 2). Nevertheless, we observed no clear influence of genotypes on olfactory response of C. sordidus, indicating that banana plants hybrids and varieties have similar attractiveness to banana root weevil.
Keywords:
Curculionidae; Musaceae; semiochemical; kairomones; varietal resistence
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