Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/14/1995
Publication Date: N/A
Interpretive Summary: The USDA's Agricultural Research Service maintains a network of repositories throughout the United States that store, regenerate and distribute plant genetic resources. These genetic resources come in the form of seeds, plants and plant parts that contain genetic information for crop breeding, new crop development, and basic research. A group of fungi (called endophytes) that infect grass germplasm stored in the USDA, ARS repository in Pullman, Washington also constitute a valuable genetic resource. These fungi confer resistance in grasses to several insect pests and may be important in the development of pest-resistant grasses. Microscopy for the detection of endophytes in grass samples is time consuming; moreover, this method requires a trained mycologist to identify endophytes in plant samples. Thus, a more rapid method is needed. The research and information presented in this paper is important because it demonstrates the potential for using aphids to distinguish between endophyte-infected and endophyte-free grass plants. This research is also a good example of team research involving scientists from three disciplines (entomology, mycology and agronomy).
Technical Abstract: Experiments were conducted to compare the expression of Russian wheat aphid Diuraphis noxia (Mordvilko), resistance in two genotypes of tall fescue gra Festuca arundinacea Schreb., harboring different isolates of Acremonium endophyte. Aphids did not select endophyte-free over endophyte-infected tiller sections in laboratory tests. In a laboratory population growth tes saphid numbers declined for 2 days on all endophyte-free plants then increa Aphid mortality was 100% on all infected plants after 4 days. Thus, antibiotic resistance to D. noxia was not specific to tall fescue genotype to Acremonium isolate. In a field plot, numbers of Russian wheat aphids we significantly higher on endophyte-free tall fescue. Using these results, a the results of other studies on Acremonium-enhanced resistance to D. noxia tall fescue and other host grasses, the potential for using D. noxia to scr grass germplasm for Acremonium fungi is discussed.