Identification of pheromone synergists in American Palm weevil, Rhynchophorus palmarum, and attraction of related Dynamis borassi

Thirteen host-plant kairomone blends, including 28 compounds, were tested and showed moderate to high synergy with rhynchophorol. The blends plus rhynchophorol also attracted the related Dynamis borassi. Ethanolethyl acetate blends in various ratios showed moderate synergy. Two blends, including 'characteristic coconut' odor molecules, were as efficient as sugarcane in synergizing rhynchophorol and field luring American Palm weevils (APWs). Preliminary olfactometer tests of natural host-plant volatiles demonstrated the role of fermentation in primary APW attraction. The synergists were chosen from a comparative study of the odors emitted by four plant materials attractive to the APW sugarcane, coconut, Jacaratia digitata tree and Elaeis guineensis (Oil palm). The volatiles were isolated during 6 days of sequential trappings onto Supelpak-2 adsorbent. The highly volatile fraction of sugarcane volatiles was sampled by solid-phase microextraction (SPME). Odors were analyzed and identified by gas chromatography and mass spectrometry. Electroantennogram responses to the plant odors were recorded to help in screening for bioactivity. The odor compositions between plants prior to and during fermentation were compared using a principal component analysis (PCA) to determine common odor features of the plants and to design simplified blends for field activity screening. About 100 components were identified in the >4-carbon fraction of the odors, among which 65% were fermentation volatiles. Fermentation generated a strong increase in the amount and variety of the volatiles emitted. The palm materials emitted two- to threefold greater odor amounts than the other plants. The odors from each plant were distinct according to PCA, with few common abundant components isopentanol, 2-methylbutanol, their acetates, acetoin, isobutyl acetate, 2,3- butanediol, and 2-phenylethanol. Ethanol and ethyl acetate accounted for 80- 90% in the highly volatile fraction of sugarcane odors. Coconut odor was mainly characterized by phenol, guaiacol, 1,2-dimethoxybenzene, ethyl esters of tiglic and 3,3-dimethylacrylic acids, 2-hexanone, 2-nonanone; and, to a lesser extent, by 2-heptanone, menthone, β-phellandrene, ethyl octanoate and decanoate, which were also present in other plants.

Bibliographic Details

Main Authors:	Rochat, D., Meillour, P. N. L., Esteban-Duran, J. R., Malosse, C., Perthuis, B., Morin, J. P., Descoins, C.
Format:	journal article biblioteca
Language:	eng
Published:	2000
Online Access:	http://hdl.handle.net/20.500.12792/3762
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