Methyl Anthranilate as a Repellent for Western Corn Rootworm Larvae (Coleoptera: Chrysomelidae).
Methyl anthranilate was identified as the active compound in extracts of maize (Zea mays L.) roots that were shown to be repellent to neonate western corn rootworm (Diabrotica virgifera virgifera LeConte) larvae. A bioassay-driven approach was used to isolate the active material from diethyl ether extracts of roots from germinating maize seeds. Separation of the extract on a Florisil column yielded an active fraction of 90:10 hexane:diethyl ether. Analysis with gas chromatography-mass spectrometry identified two compounds in the active fraction: indole (2,3-benzopyrrole) and methyl anthranilate (methyl 2-aminobenzoate). When tested in behavioral bioassays, methyl anthranilate elicited a significant (P < 0.05) repellent response at doses of 1, 10, and 100 µg. In subsequent single-choice bioassays, 1, 10, and 100 µg of methyl anthranilate prevented larvae from approaching 10 mmol/mol concentrations of carbon dioxide, which is normally highly attractive to the larvae. Indole, the other compound identified from the active fraction, did not elicit a behavioral response by the larvae. Methyl anthranilate has potential for development as a management tool for western corn rootworm larvae and may be best suited for use in a push-pull control strategy.
Department of Bioagricultural Sciences & Pest Management, Colorado State University, Fort Collins, CO 80523 (ebernklau@mac.com; andrew.norton@colostate.edu; louis.bjostad@colostate.edu), ebernklau@mac.com.
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Bernklau
USDA-ARS, 205 Curtis Hall, University of Missouri, Columbia, MO 65211 (Bruce.Hibbard@ars.usda.gov).
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Hibbard
Department of Bioagricultural Sciences & Pest Management, Colorado State University, Fort Collins, CO 80523 (ebernklau@mac.com; andrew.norton@colostate.edu; louis.bjostad@colostate.edu).
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Norton
Department of Bioagricultural Sciences & Pest Management, Colorado State University, Fort Collins, CO 80523 (ebernklau@mac.com; andrew.norton@colostate.edu; louis.bjostad@colostate.edu).
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Bjostad
D000818:Animals; D002245:Carbon Dioxide / Q000378:metabolism; D001517:Coleoptera; D004305:Dose-Response Relationship, Drug; D008401:Gas Chromatography-Mass Spectrometry; D007302:Insect Repellents; D007814:Larva / Q000254:growth & development; D010936:Plant Extracts / Q000737:chemistry; D018517:Plant Roots / Q000737:chemistry; D003313:Zea mays / Q000254:growth & development; D062367:ortho-Aminobenzoates
D007302:Insect Repellents; D010936:Plant Extracts; D062367:ortho-Aminobenzoates; D002245:Carbon Dioxide; C038892:methyl anthranilate
Diabrotica virgifera virgifera; Zea mays; host location; methyl anthranilate; repellent