ABSTRACT
The beetle Homalinotus depressus (Coleoptera: Curculionidae) is a major pest of coconuts in the Northern region of Brazil, for which environmentally friendly methods of control are desired. Behavioral responses of H. depressus to airborne volatile extracts from conspecifics suggested the presence of a male-produced aggregation pheromone. GC analyses of these extracts showed the presence of four male-specific compounds. Analytical data in combination with the synthesis of standards led to the identification of the male-released semiochemicals as epoxyisophorone (1), isophorone (2), homalinol (3), and 2-hydroxyisophorone (4), of which (3) was the major constituent. The configuration of homalinol was determined to be cis on the basis of retention times of synthetic cis and trans synthetic standards. Enantiomers of cis-homalinol were obtained in high enantiomeric excess by using biocatalysis. Their separation on a GC enantioselective column (ß-Dex325®), allowed us to unambiguously determine that the absolute configuration of natural homalinol was (1R,2R,6S). Field bioassays demonstrated that both the synthetic major compound per se and mixtures of all four male-specific compounds were attractive to H. depressus.
Subject(s)
Cyclohexanones/isolation & purification , Pheromones/chemistry , Weevils/physiology , Animals , Behavior, Animal , Chromatography, Gas , Cyclohexanones/chemistry , Female , Male , Molecular Structure , Pheromones/isolation & purification , Sex Characteristics , Weevils/metabolismABSTRACT
A new Cervellus species is described from Brazil. The male to this genus is described for the first time as well its cocoon is illustrated. The specimens parasitize the papaya borer weevil Pseudopiazurus obesus (Boheman, 1838) (Coleoptera, Curculionidae) associated with Carica papaya Linnaeus, 1753 (Caricaceae) at Rio Grande do Norte and Bahia Brazilian States.
O trabalho apresenta a descrição de uma nova espécie brasileira de Cervellus. O macho é descrito pela primeira vez; o casulo é ilustrado. Os espécimes parasitam larvas de Pseudopiazurus obesus (Boheman, 1838) (Coleoptera, Curculionidae) sobre Carica papaya Linnaeus, 1753 (Caricaceae) nos estados brasileiros do Rio Grande do Norte e Bahia.
Subject(s)
Animals , Male , Carica/parasitology , Hymenoptera/classification , Pest Control, BiologicalABSTRACT
A produção citrícola no estado de Roraima é limitada por alguns fatores, dentre os quais as pragas ocupam destaque especial. Nos últimos anos uma nova praga vem causando danos em vários pomares no Estado. Este trabalho objetivou identificar esta nova praga bem como descrever os principais sintomas e danos, visando a correta recomendação para o seu controle. Ramos e troncos infestados com o inseto, oriundos de vários pomares foram coletados e colocados em gaiolas teladas. Após a emergência, os espécimes foram mortos e acondicionados em frascos contendo álcool a 70 por cento e conduzidos para o Centro de Identificação de Insetos Fitófagos da UFPR, Curitiba-PR, para a identificação. O inseto foi identificado como Hylettus seniculus (Germar,1824)(Coleoptera:Cerambycidae),até então não citado como espécie de importância econômica para a citricultura de Roraima. Atribuiu-se sua ocorrência ao manejo fitossanitário inadequado dos pomares de citros; plantios velhos e abandonados; e a existência de hospedeiros florestais. Fatores estes considerados como favoráveis à proliferação e disseminação do inseto nos pomares.
The citriculture in Roraima state is limited by some factors, within which the pests have a special prominence. In the last years, a new plague has damaged on several orchards in the state. The objective of this work is to identify this new pest as well as to describe the main symptoms and damages, aiming a correct recommendation for its control. Infested branches and trunks were collected from several orchards and placed into cages. After emergency, the specimens were sacrificed, then conditioned in bottles with 70 percent ethanol, and lead to the Centro de Identificação de Insetos Fitófagos-UFPR, Curitiba-PR, for the identification. The insect was identified as Hylettus seniculus (Germar, 1824) (Coleoptera: Cerambycidae), until this momment, it was not cited as a species of economic importance for the citriculture of the state. Furthermore, its occurrence has been associated with inadequate fitossanitary control, old and abandoned orchards, and the existence of forest hosts. Such factors are considered favorable to the dissemination of this insect in the orchards.
