Laboratory and field evaluation of acetic acid-based lures for male Asian citrus psyllid, Diaphorina citri.

The Asian citrus psyllid (ACP) is a vector of a pathogen associated with greening and thus a major problem in citriculture worldwide. Lures are much needed for improving ACP trapping systems for monitoring populations and surveillance. Previously, we have identified acetic acid as a putative sex pheromone and measured formic acid- and propionic acid-elicited robust electroantennographic responses. We have now thoroughly examined in indoor behavioral assays (4-way olfactometer) and field tests the feasibility of these three semiochemicals as potential lures for trapping ACP. Formic acid, acetic acid, and propionic acid at appropriate doses are male-specific attractants and suitable lures for ACP traps, but they do not act synergistically. An acetic acid-based homemade lure, prepared by impregnating the attractant in a polymer, was active for a day. A newly developed slow-release formulation had equal performance but lasted longer, thus leading to an important improvement in ACP trap capture at low population densities

An improved stereospecific synthesis of (Z,E)-9, 11, 13-Tetradecatrienal. Sex pheromone component of Stenoma cecropia

(Z,E)-9,11,13-tetradecatrienal, a pheromone component of Stenoma cecropia, was prepared in 61% overall yield from 1-nonyne. The synthesis involved two palladium-catalyzed cros-couplings to afford a 1,3-dien5-yne, which was reduced with disiamylborane to obtain the corresponding triene.UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Químic

A New Method for the Preparation of 1-Ethynyl Ethers

During our study of the stannylcupration of acetylenic ethers we required [2-13C]-1 for mechanistic studies. Existing methods for the synthesis of acetylenic ethers involve dehydrohalogenation of 2-halo, 1,2-dihalo vinyl ether, or haloacetals using KOH, NaNH2, or n-BuLi. These procedures are incompatible with labile functional groups and, if applied to the preparation of 13C-labeled compounds, would require regiospecific preparation of 1- or 2-13C-labeled halo vinyl ethers, which is cumbersome. We report a new, general and efficient method for the preparation of acetylenic ethers which we have applied to the preparation of 13C-labeled and functionalized acetylenic ethersNatural Sciences and Engineering Research Council of Canada//NSERC/CanadaUniversidad de Costa Rica//UCR/Costa RicaUCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Químic

An Improved stereospecific synthesis of (Z,E)-tetradecadienal. Sex pheromone component of Stenoma cecropia

(Z,E)-9, 11-Tetradecadienal, a sex pheromone component of Stenoma cecropia, has been synthesized in 7 steps and 61% overall yield. The synthesis utilized a palladium catalyzed coupling between 9-decynyl tert-butyldinethylsilyl ether and trans-1-iodo-butene, followed by reduction of triple bond of enyne with disiamylborane. Deprotection of silyl ether and oxidation afforded the desired aldehyde.Universidad de Costa RicaUCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Químic

Stereospecific Synthesis of (E, Z)- and (Z, Z)-Hexadeca-10,12-dienal. Sex Pheromone Components of Diaphania hyalinata

Isomeric (E,Z)- and (Z,Z)-hexadeca-10,12-dienal were prepared, stereospecifically, in 51% and 43% overall yields from dec-1-yne.UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Químic

A New Method for the Preparation of 1-Ethynyl Ethers

During our study of the stannylcupration of acetylenic ethers we required [2-13C]-1 for mechanistic studies. Existing methods for the synthesis of acetylenic ethers involve dehydrohalogenation of 2-halo, 1,2-dihalo vinyl ether, or haloacetals using KOH, NaNH2, or n-BuLi. These procedures are incompatible with labile functional groups and, if applied to the preparation of 13C-labeled compounds, would require regiospecific preparation of 1- or 2-13C-labeled halo vinyl ethers, which is cumbersome. We report a new, general and efficient method for the preparation of acetylenic ethers which we have applied to the preparation of 13C-labeled and functionalized acetylenic ethersNatural Sciences and Engineering Research Council of Canada//NSERC/CanadaUniversidad de Costa Rica//UCR/Costa RicaUCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Químic

Pheromone-Trap Monitoring System for Pea Leaf Weevil, Sitona lineatus: Effects of Trap Type, Lure Type and Trap Placement within Fields

The pea leaf weevil, Sitona lineatus, is an important pest of field peas and faba beans worldwide. Present sampling techniques that rely on detection of adult feeding damage are labor intensive, time consuming and require repeated sampling. Semiochemical-based pest monitoring systems could improve pea leaf weevil management. This study, which was conducted in the Golden Triangle region of Montana, tested several factors that potentially might affect capture rates of pheromone-baited traps, including trap and lure type and trap placement. Pheromone-baited pitfall and ramp traps caught significantly more adults than ground or delta traps, in all study areas. Pitfall traps baited with gray rubber septa captured significantly more adults than traps baited with membrane formulations or controls in both pea and lentil fields. In addition, pheromone-baited pitfall traps positioned in the southern part of pea fields captured relatively higher numbers of adults than those placed in northern parts of fields, although this difference was not significant. These findings can be used to improve adult weevil monitoring and should be taken into consideration when developing an integrated pest management program

Structure, chirality, and field testing of a male-produced aggregation pheromone of Asian palm weevilRhynchophorus bilineatus (Montr.) (Coleoptera: Curculionidae)

4-Methyl-5-nonanol is a male-produced aggregation pheromone of the Asian palm weevil,Rhynchophorus bilineatus (Montr.). The pheromone was identified by coupled gas chromatographic-electroantennographic detection (GC-EAD) and coupled GC-mass spectrometric (MS) analyses of male-and female-produced volatiles. Analyses by GC-EAD and GC-MS of weevil-produced and stereoselectively synthesized isomers of 4-methyl-5-nonanol on a Cyclodex B column, which separated isomers with baseline resolution, revealed that only (4S,5S)-4-methyl-5-nonanol is EAD active and produced by the males. In field experiments in Papua New Guinea, (4S,5S)-4-methyl-5-nonanol and a racemic mixture of disatereoisomers of it enhanced attraction of male and female weevils to sugarcane-baited traps. (4S,5S)-4-Methyl-5-nonanol is also an aggregation pheromone of two other Asian palm weevils.R. ferrugineus (Oliv.) andR. vulneratus (Panz.). The stereoisomeric mixture of 4-methyl-5-nonanol is currently used to manage populations ofR. bilineatus in Papua New GuineaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones en Productos Naturales (CIPRONA

Ethyl propionate: Synergistic kairomone for african palm weevil,Rhynchophorus phoenicis L. (Coleoptera: Curculionidae)

Small trunk pieces of a freshly felled 10-year-old oil palm,Elaeis quineensis (Jacq.), were placed in a modified Nalgene desiccator, and volatiles captured for six days on Porapak Q. Gas chromatographic (GC) analysis of Porapak-Q-trapped volatiles with both flame ionization (FID) and electroantennographic detection (EAD) using male or femaleR. phoenicis antennae revealed several EAD-active compounds. They were identified as: ethyl acetate, ethyl propionate, isobutyl propionate, ethyl butyrate, and ethyl isobutyrate. In field experiments in the La Me Research Station, Côte d'Ivoire, ethyl propionate (50 mg/24 hr) but not all esters combined (50 mg/24 hr each) significantly increased capture ofR. phoenicis in pheromone-baited (3 mg/24 hr) traps. One kilogram of 1- to 3-day-old palm tissue was significantly more effective than ethyl propionate in enhancing pheromone attraction. Superior attraction of palm tissue may be attributed to additional as yet unknown semiochemicals. Alternatively, release rates and/or ratios of synthetic volatiles differed from those of palm tissue at peak attraction.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones en Productos Naturales (CIPRONA