Siegel et al. (1984) traced the origin of the endophyte to Europe, the source of tall fescue brought and planted in eastern Kentucky. Since they found that the endophyte was disseminated only by seed, the explanation for the infection of most U.S. tall fescue pastures is probably the very high demand for seed over many years when seed was harvested in June and planted in autumn of the same year, ensuring a high level of endophyte infection in the new stands. In later years when adequate seed supplies were available, it is likely that some old seed from the previous year, containing dead endophyte, was planted and resulted in low-endophyte or E- pastures.
Funk et al. (1983) stated at a meeting in Oregon that endophytes not only conferred pest resistance, already reported by Prestridge et al. (1982) in New Zealand with perennial ryegrass, but also improved drought resistance in turfgrasses. He also made a significant statement, "Additional research is needed to fully understand the role of endophytes and their significance in biology and agriculture." This became quite apparent after the premature release of E- tall fescue with no understanding of endophyte effects on the host plant. A mutualistic relationship exists between the endophyte and host plant (Bacon and Siegel, 1988; Siegel et al., 1984). A major benefit is much greater resistance to drought stress (Bouton et al., 1993; West et al., 1993), partially a result of deeper root development (Richardson et al., 1990) (see Chapter 4). Thus, the endophyte is important for plant persistence in stressful environments and under close continuous grazing. Endophytes can increase plant tillering, improve utilization of soil N (Arachevaleta et al., 1989), and enhance persistence during drought. The endophyte receives nutrients, protection, reproduction, and dissemination from the host plant while the latter receives improved tolerance to drought, insects, diseases, and nematodes, as well as greater seedling vigor and growth potential (Latch, 1997). With all the benefits of the endophyte, it is clear that E- tall fescue is handicapped in a stressful environment and less competitive with other plants.