Cropmark Seeds' New Endophyte Grass

Fifteen years of patient work by plant breeders for Cropmark Seeds have produced a pasture which contains a new novel endophyte confering widespread insect resistance without animal health problems. The plant is a cross between meadow fescue and perennial ryegrass, such cross being termed a festulolium. The endophyte which is called GrubOUT U2, protects the grass against root feeding and top feeding insects.

New Zealand leads the world in pasture research which has established that the fungi living in symbiotic relationships in ryegrasses are implicated in animal health issues like grass staggers and ergovaline heat stress. But at the same time the lolium endophytes (fungi) are a defence mechanism for the plant against the attacks of insect pests like Argentine stem weevil, which can attack the pasture sward and make it unproductive. AgResearch scientists discovered that endophytes could be removed from ryegrass seeds, and different or “novel” endophytes could be replaced. Nil endophyte removed the animal health issues from the grazed plant but also took away the defence mechanism for pasture pests. Novel endophyes such as AR1 and AR37 combine the best of both issues – lower animal health issues while retaining insect resistence. But they only protect against some of the widely found pasture pests, and not those which feed on roots of plants. Cropmark Seeds has spent 15 years researching and trialling other naturally occurring endophytes which will deter a wider range of common insect pests of grasses.

GrubOUT U2 is a strain of the Neotyphodium uncinatum endophyte which is found naturally in meadow fescue and produces chemcials called lolines which protect the plant against a wide range of pasture pests both above and below the ground level such as grass grub larvae, black beetle adults and larvae, Argentine stem weevil, porina caterpillar and red-headed pasture cockchafer. Other research evidence suggests that U2 will also protect against the black field cricket, pasture mealybug, root aphid and soil nematodes.These lolines are known to act as feeding deterrents to insect pests which are pasture pests but have no adverse animal effects, like grass staggers or heat stress.

Lolines also accumulate in the plant roots, unlike other novel endophytes (AR1 and AR37) which stay only in the foliage. The larvae of pests will be repelled, and not just the adults.

Cropmark Research Director Nick Cameron began in the late 1990’s crossing meadow fescues with perennial ryegrasses, because until that time no-one had successfully combined the meadow fescue endophyte with ryegrasses. While the endophyte wouldn’t persist in ryegrass it does persist in the meadow fescue cross with ryegrass, which Cropmark is calling festulolium.

Fescues also bring some other natural advantages, such as good metabolisable energy (ME), digestibility and disease resistance.These were put through agronomic trials, insect pest trials, livestock safety and livestock performance trials, both at the Cropmark research station at Darfield as well as contracted trials with universities and other organisations.

Cropmark is releasing the GrubOUT U2 endophyte in the festulolium seed from March onwards as part of a Barrier Combo mix of two festuloliums, plus medium and large-leaved white clovers, sown at a recommended rate of 25kg/ha. Cropmark recommends full pasture or crop replacement (either by full cultivation, or direct drilling) and against under-sowing into existing pastures. While U2 protects plants against pests, it does not eradicate them, so existing pastures would be a pest haven, and compete against GrubOUT pastures for establishment.

All endophytes are not fully established in the plant for six to eight weeks after germination, so treated seed provides insect protection until them. Slug and snail baits may also be needed. Once established, Cropmark believes that GrubOUT U2 pasture will persist longer than grass/endophyte combinations which are susceptible to black beetle or grass grub infestation. Once established the endophyte which grows between the cell walls of the host plant, will remain for the life of the plant. It will not however spread to other plants nearby.

Alll claims being made for the new grass and its new endophyte are based on credible research and trial results, the majority of which are peer-reviewed, published scientific papers.