Submitted to: International Neotyphodium Grass Interactions
Publication Type: Other
Publication Acceptance Date: 3/15/2004
Publication Date: 5/23/2004
Citation: Clement, S.L., Elberson, L.R., Waldron, B.L., Kisha, T.J. 2004. Variable effects of wild fescue--neotyphodium associations on bird cherry-oat aphid survival. In: Kallenbach, R., Rosenkuans, C. Jr, Lock, T.R., editors. Proceedings 5th International symposium on Neotyphodium/Grass Interactions. Paper No. 308.
Technical Abstract: Temperate grass - Neotyphodium associations have widely varying effects (negative to positive) on insect herbivores, as revealed by studies on domesticated and wild grasses and their phytophagous insect associates. For example, bird cherry-oat aphid (BCOA) survival was adversely affected by some but not all wild tall fescue - Neotyphodium associations (Clement et al. 2001. Crop Sci. 41:570-576). In this poster, we provide more evidence that Neotyphodium infection does not always render wild Tunisian fescue resistant to BCOA. Research in progress is characterizing the identity of this material, which may represent 1-2 species or interspecific hybrids (Festuca arundinacea, F. pratensis, interspecific hybrids between these species). BCOA overlaps in its geographic distribution with the native range of tall fescue, which includes North Africa. In a glasshouse experiment involving a larger number of fescue accessions than were evaluated by Clement et al. (2001), we found that 14 of 17 infected populations from Tunisia supported significant BCOA reproduction and population growth. When four infected and BCOA-susceptible populations were re-evaluated in a second experiment, they again exhibited susceptibility to the aphid.. These results are further evidence that Neotyphodium - infected wild grasses may or may not adversely affect the survival of insect associates. We posit that variation in alkaloid type and concentration mediated BCOA responses to the different wild fescues.