Endophyte is a fungus that occurs naturally in many grass species, including ryegrass. It provides the plant with improved insect tolerance, and in return the plant provides the endophyte with a place to live and reproduce.

Endophyte is extremely important to farmers as it has a dramatic effect on the persistence and production of ryegrass pastures in most regions of New Zealand. There are now several novel endophytes available, and each can provide different levels of insect protection and effects on grazing animals.

At Agricom, we market the AgResearch novel endophytes AR1 and AR37 in most of our ryegrass cultivars, as well as providing low endophyte (LE) options. AgResearch novel endophytes are thoroughly developed and tested with world-renowned science, with emphasis placed on testing effects on animals, insects, pasture production and persistence.

Where insect pressures are low, AR1 is an excellent option for animal health and production, and provides good pasture persistence in many regions. AR37 is increasingly being used in regions where other endophytes are not providing enough insect protection; these insects negatively affect pasture persistence and production. AR37 provides ryegrass the best long term, natural protection from porina and root aphid, along with other common insects. Several trials have confirmed both pasture production and persistence advantages of AR37 over AR1 and standard endophyte.

Animal performance of both sheep and milk production in dairy cows is the same when animals are fed perennial ryegrass with AR37, when compared with AR1 or nil endophyte. The combination of the insect tolerance and persistence advantages makes AR37 a valuable technology for many farmers.

AR37 can cause ryegrass staggers. In perennial ryegrass with AR37, trials have shown that on average the frequency, duration and severity of ryegrass staggers is less than for standard endophyte. However on occasions sheep (and potentially other animals) grazing AR37 ryegrass may be severely affected. After many years of use on commercial dairy farms, ryegrass staggers have not been observed in dairy cows on-farm to date. AR37 varieties should not be used on properties grazing either deer or horses.

Endophyte Content
Ryegrass with AR37 endophyte (right) demonstrates persistency advantages over AR1 endophyte (left) in the same cultivar, with black beetle insect pressure in the Waikato.
Endophyte Compare
Effects of different endophytes on pasture under insect pressure in Canterbury.


AR37 is a novel endophyte that produces none of the alkaloids found in other commercially available endophytes. It produces a unique type of alkaloid - epoxy-janthitrems - which have never been found in any other ryegrass/endophyte combination. AR37 has resistance to more pasture insects than any other ryegrass endophyte commercially available including black beetle adults, pasture mealy bug, root aphid, porina and Argentine stem weevil larvae.


 Where insect pressures are low, ryegrass with AR1 endophyte is an excellent option for animal health and production. Pastures with the AR1 endophyte are protected against Argentine stem weevil and pasture mealy bug, but deliver only a low level of control against black beetle.


MaxP® endophyte technology improves tall fescue resistance to Argentine stem weevil, black beetle, cutworm, pasture mealy bug, and root aphid.

Low Endophyte

Ryegrass without endophyte or with low levels of endophyte provide little or no protection against common insect pests.

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