Author
RANGER, C - UNIV OF MO-COLUMBIA | |
WINTER, R - UNIV OF MO-ST LOUIS | |
Backus, Elaine | |
ROTTINGHAUS, G - UNIV OF MO-COLUMBIA | |
ELLERSIECK, MARK - UNIV OF MO-COLUMBIA | |
JOHNSON, D - CAL/WEST SEEDS, INC |
Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 1/20/2005 Publication Date: 4/1/2005 Citation: Ranger, C.M., Winter, R.K., Rottinghaus, G.E., Backus, E.A., Ellersieck, M., Johnson, D. 2005. Discrimination by the potato leafhopper (homoptera: cicadellidae) of host volatiles from resistant and susceptible alfalfa, medicago sativa l. Environmental Entomology. 34(2):271-280 Interpretive Summary: 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 G98A and susceptible, nonglandular M. sativa Ranger. Gas chromatography-mass spectrometry determined that steam distillates from both both varieties were composed of diverse alcohols and esters. No volatiles were unique to either G98A or Ranger, but one acetate and one alcohol were frequently collected in lower amounts from G98A compared to Ranger. Two-choice bioassays of leaf steam distillates and head-space samples found significantly more adult female potato leafhoppers oriented towards volatiles from Ranger than G98A. Instead of producing volatile repellents as previously suggested, glandular-haired G98A might be less attractive to the potato leafhopper. This information will aid alfalfa breeders in improving the glandular-hair trait. Technical Abstract: 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 G98A and susceptible, nonglandular M. sativa 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 most predominant compound in steam distillates, and (Z)-3-hexenyl acetate and (Z)-3-hexen-1-ol as other major components. In contrast, (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, but (Z)-3-hexenyl acetate and 1-octen-3-ol were frequently collected in lower amounts from G98A compared to Ranger. Two-choice bioassays of leaf steam distillates and head-space samples found significantly more adult female 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 in two-choice bioassays. Instead of producing volatile repellents as previously suggested, glandular-haired G98A might be less attractive to the potato leafhopper. |