Monday, November 13, 2006

Fungicide Effects on Turf-Type Tall Fescue Endophyte Infection.

Kristina S. Walker1, Cale Bigelow1, Douglas Richmond2, and Glenn Hardebeck3. (1) Purdue University, 3164 Stratus Drive, 3164 Stratus Drive, West Lafayette, IN 47906, (2) "Purdue Univ. - Dept, of Entomology", 901 W. State St., 901 W. State St., West Lafayette, IN 47907, United States of America, (3) Purdue Univ., 915 West State St., 915 West State St., West Lafayette, IN 47907-4773, United States of America

Endophytes are known to enhance agronomic performance of turfgrasses. However, little is known about the effects of fungicide applications on endophyte persistence when applied to seedlings. Eight commercially available fungicides used for brown patch control were applied to late-summer seeded ‘DaVinci’ turf-type tall fescue seedlings in the field to assess their effects on endophyte expression. Fungicides were applied at either 7 or 21 days after seedling emergence (DAE) and endophyte infection of the pseudostem was determined with commercial immunoblot test kits on tillers 2 months after seeding. Endophyte expression ranged from 33-60 % and 30-50 % for applications made at 7 and 21 DAE, respectively. Eagle, Cleary’s 3336, and Insignia had the greatest influence on endophyte expression when applied 7 DAE, decreasing endophyte presence to 33, 37, and 37 %, respectively. When applied 21 DAE, Eagle, Tartan, and Banner Maxx had the greatest influence on endophyte expression decreasing endophyte infection rates to 37, 30, and 37 %, respectively. Prostar and Heritage (60 %) applied 7 DAE and Cleary’s 3336 and Prostar (50 %) applied 21 DAE had the least effect on endophyte infection rates. Although there were slight differences between treatments, these differences were not significant, and none of the fungicides seemed to have a strong negative influence on endophyte infection.