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ARS Home » Southeast Area » Fort Pierce, Florida » U.S. Horticultural Research Laboratory » Subtropical Insects and Horticulture Research » Research » Publications at this Location » Publication #215701

Title: Host plant kairomones for the tropical weevil Diaprepes abbreviatus

Author
item HAMMOCK, J - Non ARS Employee
item Alessandro, Rocco
item Lapointe, Stephen
item Dickens, Joseph

Submitted to: Arthropod-Plant Interactions
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/26/2009
Publication Date: 3/31/2009
Citation: Otalora Luna, F., Hammock, J.A., Alessandro, R.T., Lapointe, S.L., Dickens, J.C. 2009. Host plant kairomones for the tropical weevil Diaprepes abbreviatus. Arthropod-Plant Interactions. 3: 63-73.

Interpretive Summary: The root weevil, Diaprepes abbreviatus, is a major pest of citrus, sugar cane, and many ornamental plants of economic importance. It was accidentally introduced from the Caribbean into Florida in the 1960’s and its range within the United States has now expanded to include Texas and California. Thus far, no safe and effective control method has been developed for this species. The odors from a host plant and from the weevils themselves were collected, identified, and tested for their effect on weevil olfaction and behavior. Using an electroantennogram, antennal responses were recorded to several plant odors found in citrus leaves. A behavioral assay was used to determine the response of adult D. abbreviatus when allowed to choose between an odor source and a control. A blend of three compounds elicited significant attraction. The biologically active compounds found here likely play a role in host finding by D. abbreviatus and other interactions of the insect with its hostplant.

Technical Abstract: The tropical root weevil Diaprepes abbreviatus (L. 1758) (Coleoptera: Curculionidae) is a polyphagous insect from the Caribbean Islands and an invasive insect in the southern part of United States where it is pest of citrus crops and ornamental trees. Adults feed upon foliage where aggregation, mating and oviposition take place. Here, the headspace vapors above a hostplant of D. abbreviatus [Citrus macrophylla Wester (Rutaceae)] and adults feeding on their hostplant were collected by aeration and solid-phase microextraction (SPME) then analyzed by gas chromatography-linked mass spectrometry (GC-MS). Electrophysiological responses of weevil antennal receptors to volatile headspace extracts and synthetic compounds were recorded by gas chromatography-linked electroantennographic detection (GC-EAD) and electroantennograms (EAGs). Separation of volatiles using GC revealed a preponderance of monoterpenes in the headspace of citrus leaves and adults feeding on the leaves. Antennal responses were recorded to (R)-(-)-linalool, citronellal, nerol, citral and carvacrol. When comparing EAGs between (+/-)-linalool and (R)-(-)-linalool, no significant difference was found; responses to (R)-(+)-citronellal were larger than for (S)-(-)-citronellal. An open T-track dual choice olfactometer measured behavioral responses to electrophysiologically active compounds and several blends. Among the individual compounds and blends tested, only the blend of (+/-)-linalool, cis-3-hexen-1-ol and carvacrol (source dose 25:25:2.5 µg) elicited significant attraction. The biologically active compounds found here likely play a role in host finding by D. abbreviatus and other interactions of the insect with its hostplant.