Debunking Endophytes

Table of Contents

  1. Debunking Endophytes
  2. What is an Endophyte?
  3. Endophytes and Insect Tolerance
  4. Endophytes and Stress Tolerance
  5. How are Endophytes Passed on From Generation to Generation?
  6. Effect of Seed Storage on Endophytes
  7. What Role Can Endophytic Turfgrasses Play in Turf Management?
  8. Related Links

Debunking Endophytes

The word endophyte keeps cropping up in magazine articles, talks and in seed advertisements. Associated with it are all sorts of claims of insect resistance, stress tolerance, etc. This article will attempt to give you the facts as well as point out some precautions when buying seed containing endophyte.

What is an Endophyte?

An endophyte is a fungus which grows inside a plant. The endophytes that we are most concerned with are the ones growing inside a turfgrass plant. These endophytes, unlike disease causing fungi, do not cause any harm to the turfgrass plant. Currently, endophytes have been found in tall fescue, perennial ryegrass, hard fescue, chewing fescue and creeping red fescue. There are no known endophytes occurring in Kentucky bluegrass or creeping bent grass. Endophytes are found in all parts of the plant except the roots with the highest concentration found in the leaf sheath.

Endophytes and Insect Tolerance

The discovery that high endophyte grasses were resistant to insect feeding was accidental. A study in New Zealand was looking at the effect of endophytes on sheep grazing. After this study it was discovered that when the tall fescue was growing in after grazing that the endophyte free tall fescue was being attacked by a grass pest called the Argentine Stem Weevil but the high endophyte plot was not attacked.

Since this chance discovery many research reports on turfgrass species containing endophytes have shown that they enhance resistance to surface feeding insects including sod webworm, bill bugs and chinch bugs. The endophyte either produces a poison or makes the plant produce a chemical which repels insects that feed on turf. Studies have shown that the amount of insect resistance is directly proportional to the percentage of endophyte living within the turfgrass plant (Figure 1).

Figure 1: The plot on the left is a non-endophyte enhanced cultivar showing insect feeding damage.
Figure 1: The plot on the left is a non-endophyte enhanced cultivar showing insect feeding damage. The plot on the right is endophyte enhanced and resistant to insect feeding.

Endophytes and Stress Tolerance

Endophyte enhanced turfgrasses have shown increased stress tolerance. This has been expressed by reduced weed invasion, better summer survival and fall recovery after a drought. The reasons for the enhanced stress tolerance are not well understood.

How Are Endophytes Passed on From Generation to Generation?

A turfgrass plant containing endophytes will have endophytes in the leaves and sheath. When that plant goes to seed the endophytes will grow into the seed also. As long as those seeds containing the endophytes are properly stored those endophytes will remain in the seed. When that seed germinates and grows into a turfgrass plant the resulting plant will also contain the endophyte.

Effect of Seed Storage on Endophytes

The endophytic fungus which is present in turfgrass seed at the time of harvest can lose its viability very quickly if it is not stored under proper conditions. The storage conditions necessary to maintain endophyte viability in the seed are cool dry conditions. According to some studies conducted with tall fescue at a temperature of 5°C seed containing 100% endophytic fungi can be stored up to 15 months without losing the viability of the endophytes. On the other hand endophytic seed stored at 21°C will lose 40% of its endophytes in 7 months and all of its endophytes in 11 months.

What Role Can Endophytic Turfgrasses Play in Turf Management?

Due to the inherent insect resistance of endophytic grasses they are a useful tool in an integrated pest management (IPM) approach to turf management. Seeding with perennial ryegrass, tall fescue, hard fescue, chewing and creeping red fescue containing endophytes whenever possible, will reduce reliance on pesticides for control of above ground feeding insects. Added to this is the enhanced stress tolerance making your job as a turf manager easier. A list of turf cultivars which contain endophytes can be found in OMAFRA Publication 384, Turfgrass Management Recommendations or see Table 1. As well, information with regard to species and cultivars which contain endophytes can be obtained from your seed supplier.

Table 1. Ontario Turfgrass Varieties Containing Endophytes
Species Cultivars
Creeping Red Fescues Herald
Jasper E
SR 5200 E
Chewings Fescue Bridgeport
Jamestown II
Koket
SR 5000
SR 5100
Treazure
Southport
Victory E
Hard Fescues Nordic
Reliant
SR 3000
SR 3100
Sheep Fescues SR 3200
Turf -Type Perennial Ryegrass Accolade
Achiever
Affinity
APM
Birdie II
Buccaneer
Citation II
Competitor
Cutter
Dandy
Dasher II
Delaware Dwarf
Dimension
Divine
Edge
Elf
Elf Dwarf
Envy
Express
Fiesta II
Gettysberg
Jazz
Manhattan II
Omega II
Palmer
Panther
Pinnacle
Prelude
Premier
Prizm
Repell II
Saturn II
Seville
Sovereign
SR 4000
SR 4010
SR 4100
SR 4200
SR 4300
SR 4400
Stallion
Stallion Select
Yorktown III
Wizard
Tall Fescue Adobe
Apache
Aquara
Arid
Aztec
Bonanza
Bonsai
Chieftan
Coyote
Empress
Finelawn I
Gazelle
Jaguar III
Mirage
Mustang II
Pixie
Rebel 3D
Rebel II
Rebel Jr.
SR 8200
SR 8210
SR 8300
Tribute
Titan
Twilight
Vegas
Winchester

Related Links


For more information:
Toll Free: 1-877-424-1300
E-mail: ag.info.omafra@ontario.ca
Author: Pam Charbonneau -Turfgrass Specialist/OMAFRA
Creation Date: 1997
Last Reviewed: February 2006