Common Questions

What is an endophyte?

An endophyte is a fungus found naturally in many grass species, including ryegrass. It provides the plant with protection from insects, and in return the plant provides the endophyte a place to live and reproduce. An endophyte is essentially an ‘in-built insecticide’.

What is a novel endophyte?

A novel endophyte is a naturally occurring endophyte that has been identified as having properties that make it more useful in agriculture than other (‘standard/high’) endophytes. These properties usually include better insect protection for its host plant, and /or reduced side effects on grazing animals. Examples of novel endophytes are AR1, AR37, MaxP® & Endo5.

How long has AR37 been commercially available?

AgResearch together with its commercial partners began work on developing the AR37 endophyte in 1995. Ryegrasses with AR37 endophyte were released commercially in autumn 2007.

Why Use AR37?

AR37 from AgResearch, has been widely tested by them as well as in a three year trial by Dairy NZ, AR37 delivers an unbeaten level of protection against insects compared to any other commercially available ryegrass endophyte.

Plants with the AR37 endophyte have protection, once established, against adult black beetle, Argentine stem weevil larvae, root aphid, pasture mealy bug and porina. These insects all have a strong role in a reduction in the productivity and longevity of the ryegrass.

Who should use AR37?

Farmers who want improved pasture production, persistence and animal performance from their pastures should use AR37, especially where damaging insects are likely to be present. Trials that have been undertaken show that AR37 is a suitable pasture for dairy cows, sheep, and beef animals.

Will AR37 solve my pasture persistence issues?

There are many factors involved with pasture persistence including correct pasture establishment, over grazing, stock damage, insects and soil health to name a few. AR37 endophyte will reduce the effects that insects play in the reduction of pasture persistence, but if there are other factors involved it will not stop pasture loss

Are there any issues with animal performance or health?

In a three year DairyNZ grazing trial, milk production from AR37 and AR1 pastures was not significantly different, on a whole season basis, in any year. Lambs grazing AR37 ryegrass have very good production but this production can be reduced in the event of ryegrass staggers.

AR37 can cause ryegrass staggers. 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.

How should pasture with AR37 be established?

As with new AR1 endophyte pastures, all existing ryegrass plants should be removed from the paddock (using spraying and/or ploughing), and old ryegrass seed buried or germinated (following multiple spray applications or cropping) before planting ryegrass with AR37. Re-establishment of old ryegrass plants will not result in failure but can reduce animal performance (if old ryegrass has standard endophyte), pasture production and possibly persistence.

How good is AR37 endophyte?

AR37 endophyte is the best commercially available endophyte for ryegrass insect protection. AR37 endophyte is widely tested and has resistance to more insects than NEA2, AR1 or standard endophytes.

Does AR37 protect against porina?

Relative to other novel endophytes in ryegrass AR37 delivers an unbeaten spectrum of insect control, and should be used as standard practice for areas at risk of porina attacks. It has three stars on the insect control table indicating that that it provides Good control: AR37 markedly reduces insect damage under low to moderate insect pressure. Damage may still occur when insect pressure is high. Moderate pressure occurs at levels up to approximately 100 porina /m2 or 4 porina per standard spade. Pasture production is reduced when 20 - 40 porina/m2 are present. At this level they consume the equivalent amount of dry matter as 1 SU/ha. Higher porina numbers cause plant deaths in unprotected pastures. At 100 porina/m2 and greater high to extreme pressure is exerted on the pasture which AR37 alone cannot protect against.

No endophyte prevents porina moths laying eggs in pasture. However caterpillars that hatch from eggs in an AR37 pasture will be killed if they eat AR37 infected grass. In mixed pastures other plants may provide a safe feed source and this means porina are often found at low levels in pastures based on AR37 ryegrass, but the endophyte is still working and will deter and poison the caterpillars. No other ryegrass endophyte has been proven to deliver an equivalent level of protection against porina. It should be noted that in cold conditions during late autumn and winter the effectiveness of porina control may be reduced.