The Diagnosis of the Tall Fescue Endophyte
Tom Hooper, Animal Disease Diagnostic Laboratory
Keith Johnson, Extension Specialist, Forages
Purdue University Animal Disease Diagnostic Laboratory,
Southern Indiana Purdue Agricultural Center
Cooperative Extension Service
West Lafayette, IN 47907
In 1931 Dr. E. N. Fergus of the University of Kentucky became interested in a tall
fescue growing in Kentucky. He collected seed and his subsequent tests led to the release
of "Kentucky 31" in 1943. This variety now grows on most of the tall fescue
acreage in the United States. This grass was found to be well-adapted, easy to establish,
tolerant to a wide range of management practices, and produced good forage yields.
Laboratory analysis of fescue compares favorably to many other cool-season grasses in
However, this new grass was not without its problems. Performance of animals grazing
fescue was often variable and disappointing. In the mid- 1970's, researchers noted a
difference in the performance of animals grazing different fescue fields. The toxic
pastures were found to contain high levels of a fungus growing within the plant
This fungus, (Acremonium coenophialum), has two characteristics of practical
- 1. The organism does not affect appearance of the grass; thus, it rakes laboratory
analysis to detect its presence.
- 2. It is seed-transmitted and apparently not transmitted any other way. Once an infected
stand is established it will remain infected.
With knowledge about the presence of the fungus and the level of infection, management
decisions can be made to help improve animal performance.
There are several situations where livestock producers can use this testing to their
advantage. Information on the level of, or the lack of, infestation should be used in
making decisions on the management of a particular field. These practices include pasture
fertilization, rotation, renovation, or reestablishment.
An approximation of the level of infestation can be made by collecting plant material
from the field and submitting it for analysis.
Fescue seed can also be tested for the presence or absence of the fungus. For
information on this type of testing please contact the laboratory.
Results are usually available within one week of receipt of the sample. The individual
submitting the sample will be notified by mail. Recommendations and interpretation of test
results can be received by contacting Keith Johnson, Purdue University Forage Specialist,
at (317) 494-4800.
A charge will be made for this laboratory analysis to partially cover the costs
involved. Please contact the laboratory for current charges.
Collecting tall fescue tillers (cut tillers on right) for diagnosis of the tall fescue
To determine the infestation level of a pasture, it is necessary to obtain a good plant
tissue sample for analysis. Before the plants form seed heads, the fungus is concentrated
in the tiller (stem). A minimum of 50 tillers are required for each field sampled. Only
one tiller should be taken from the crown of each random plant selected. The lowest 4-6
inches of an actively growing large tiller should be cut off at ground level and
submitted. Be careful to avoid ditches and fence rows that may not be typical of the field
as a whole. In mixed stands, take care not to collect any grasses other than fescue; if
there is a question, please submit the entire stem or contact your Cooperative Extension
Service Agricultural Agent for help in identification.
The ideal packaging method is to wrap the tillers in a damp paper towel and seal in a
plastic bag. Samples should be sent immediately to the laboratory by first-class mail in a
padded envelope or cardboard box. Please collect and mail samples so they will arrive at
the laboratory during the weekdays. Samples should be mailed to:
- Animal Disease Diagnostic Lab
Southern Indiana Purdue Agricultural Center
11367 E. Purdue Farm Road
Dubois, IN 47527-9666
- Phone (812) 678-3401
Questions can be directed in writing or by calling the laboratory.
Name _________________________________ Name or number of field __________________
Phone number (___)____________________ Size of field (acres)_____________________
Address ______________________________ Age of field (years) _____________________
______________________________________ Fescue variety if known __________________
AY-275 New 3/93
The Cooperative Extension Service of Purdue University is an affirmative
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