Wednesday, 17 November 2004
D0613

Discrimination by the potato leafhopper of host volatiles from resistant and susceptible alfalfa

Rudolph E. K. Winter, ranger@aesop.rutgers.edu, University of Missouri, Department of Chemistry and Biochemistry, 315 Benton Hall, 8001 Natural Bridge Road, St. Louis, MO, Christopher M. Ranger, cmr0b2@mizzou.edu, University of Missouri, Department of Entomology, 1-87 Agriculture Building, Columbia, MO, Elaine Backus, ebackus@fresno.ars.usda.gov, USDA-ARS PWA, San Joaquin Valley Agric. Sci. Ctr., Exotic & Invasive Diseases & Pests Research, 9611 So. Riverbend Ave, Parlier, CA, and George Rottinghaus, University of Missouri, D202 Vet. Med. Diag. Lab, Columbia, MO.

Varieties of glandular-haired alfalfa, Medicago sativa L., with resistance to the potato leafhopper, Empoasca fabae (Harris), have been commercially released. To assess the role of volatile organic compounds in leafhopper resistance, stem and leaf volatiles were collected using vacuum steam distillation and head-space analysis from resistant, glandular-haired M. sativa cv. ‘G98A’ and susceptible, nonglandular M. sativa cv. ‘Ranger’. Gas chromatography-mass spectrometry determined that steam distillates from both G98A and Ranger were composed mainly of alcohols and esters, with 1-octen-3-ol frequently being the predominant compound in steam distillates, and (Z)-3-hexenyl acetate and (Z)-3-hexen-1-ol as other major components. (Z)-3-hexenyl acetate was the only major component in head-space samples from G98A and Ranger. No volatiles were unique to either G98A or Ranger. Two-choice bioassays of leaf steam distillates and head-space samples found significantly more potato leafhoppers oriented towards volatiles from Ranger than G98A. However, leafhoppers were not attracted to either (Z)-3-hexenyl acetate or 1-octen-3-ol when tested singly. Leafhoppers may be more attracted to M. sativa Ranger than M. sativa G98A.


Species 1: Hemiptera Cicadellidae Empoasca fabae (potato leafhopper)
Keywords: volatiles, repellents

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