Thursday, July 7, 2022

Insect resistance rewards patience

Fifteen years of patient work by plant breeders for Cropmark Seeds have produced a new pasture plant with a novel endophyte promising widespread insect resistance without animal health problems.

PAINSTAKING WORK: Cropmark research director Nick Cameron who started crossing meadow fescues with perennial ryegrasses in the late 1990s. Photo: Johnny Houston

One of the smaller Kiwi-owned seed companies, Cropmark says it is a world-first and expects export demand will be strong, although initial preference will be given to the home market.

GrubOUT with U2 endophyte will be available to farmers for pasture renewal next autumn within what Cropmark is calling the Barrier Combo seed mix, and being marketed in advance.

Once established via treated seed, the symbiotic endophyte protects host plants against grass grub larvae, black beetle adults and larvae, Argentine stem weevil, porina caterpillar and red-headed pasture cockchafer.

These are both above and below ground pasture pests which pose the biggest threats to pasture establishment and persistence.

Cropmark research director Nick Cameron began in the late 1990s crossing meadow fescues with perennial ryegrasses because meadow fescue contains Neotyphodium uncinatum endophyte (fungus) which produces chemicals called lolines.

These lolines were known to repel insects which are pasture pests but have no adverse animal effects, like grass staggers or heat stress.

Lolines also accumulates in the plant roots, unlike other novel endophytes (AR1 and AR37) which stay only in the foliage.

However, Cameron’s challenge was to successfully introduce and maintain the new endophyte into ryegrass plants and/or their crosses, which had never been done before.

Fescues have some other natural advantages, such as good metabolisable energy (ME), digestibility and disease resistance.

He came up with new crossbred pasture species Cropmark is calling festuloliums which contain the lolines.

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.

Exhaustive testing has been carried out. For instance Cropmark does about 60,000 endophyte tests each year, Cropmark marketing manager, Garry Begley, said.

However, research assistance from AgResearch has not been available because of its contracts with PGG Wrightson.

The claims for festulolium and U2 endophyte have all been established in the scientific literature and in trials.

“But we ourselves are our greatest watchdog, because the potential for this technology is huge, both here and overseas, and if we make invalid claims our credibility is at risk.

AgResearch has been researching lolines also, with a view to getting them into different products, however Cropmark is now leading the world in interspecies grass crossing and successfully introducing and maintaining this novel endophyte,” Begley said.

The Barrier Combo mix contains two of the festuloliums with U2 endophyte and medium and large leaved white clovers, sown at a recommended rate of 25kg/ha.

Cropmark clearly wants to sell seeds, to recoup the research outlay and maintain the privately owned company, and it believes this combo gives the best odds of successful and productive pasture establishment.

It recommends full pasture or crop replacement and against under-sowing. While U2 protects plants against pests, it does not eradicate them, so existing pastures would be a pest haven and compete against GrubOUT 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.

Cropmark concedes that yields from Barrier Combo will be less in the first year than its own Ultra ryegrass because of slower establishment, but once established it should be comparable and over time out-yield other ryegrass/endophyte combinations because of the better insect resistance.

In comparison with AR37 endophyte, the U2 endophyte is the first to bring root protection, so that pest larvae will be repelled, and not just adults.

The Barrier Combo mix will retail at the top end of the market for price, alongside of the AR37s, Begley said.

Many farmers have already made enquiries about seed availability, especially from provinces with high pasture pest pressures, like black beetle above Taupo and grass grub in Canterbury.

GrubOUT seeds and U2 endophytes are aimed at both dairy and drystock farmers, he said.

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