Fungal Endophyte Effects on Production of Legumes in Association with Tall Fescue

Abstract

The fungal endophyte, Neotyphodium coenophialum (Morgan‐Jones & W. Gams) Glenn, Bacon & Hanlin (syn. Acremonium coenophialum Morgan‐Jones & W. Gams) is generally considered to enhance the competitive ability of tall fescue (Festuca arundinacea Schreb.) with legumes, but substantiating field data are limited. Our objectives were to determine if endophyte infection of tall fescue affects stand density and forage production of (i) red clover (Trifolium pratense L.), ladino clover (T. repens L.), and alfalfa (Medicago sativa L.) harvested at 3‐wk intervals and (ii) alfalfa at low and high seeding rates harvested at 3‐wk and 9‐wk intervals. The first study compared alfalfa, red clover, and ladino clover in association with ‘Jesup’ E+ (endophyte‐infected) and E− (endophyte‐free) tall fescue, harvested at 3‐wk intervals for 3 yr. The second study had alfalfa broadcast planted at 11.2 and 22.4 kg ha−1 with E+ and E− tall fescue planted broadcast at 11.2 and 22.4 kg ha−1 or in rows at 22.4 kg ha−1. This was harvested at 3‐wk intervals for 3 yr, then at 5‐wk intervals for 1 yr. In the first study, clovers and alfalfa cut at 3‐wk intervals for 3 yr had similar (P > 0.05) legume yields when grown with both E+ and E− tall fescue. In the second study harvested at 3‐wk intervals, E+ tall fescue adversely affected (P < 0.05) the associated alfalfa the second year, and by the third year the yield of alfalfa planted at 22.4 kg ha−1 in mixture with E+ tall fescue was only 71% of alfalfa with E− tall fescue (P < 0.05). Similar differences occurred the next year when cut at 5‐wk intervals. Stands of alfalfa or tall fescue after 4 yr were not affected (P > 0.05) by endophyte. The results suggest that endophyte infection of tall fescue increases competition with legumes, but it may be modified by seeding rates or grass sod density.