Department of Agriculture principal pasture agronomist Gavin Peck and pasture agronomist Ted Callanan have revealed a four year trial had shown the grasses most tolerant to pasture dieback were Signal grass and Mekong Brizantha as well as Buffel grass varieties Biloela and Tarewinnabar.
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"We found the varieties landholders should avoid included Bisset Creeping blue grass and Gayndah Buffel, digit grasses, Bambatsi panic and Kikuyu, Mr Peck said.
As pasture dieback maintains its grip across the state, attendees at the Boonah field day on May 21 heard from Mr Peck and Callanan the results of an innovative trial which assessed which of 29 grass varieties had the highest and lowest tolerance to mealybug.
According to one grazier, the results have changed his mind as to which grass varieties were more resilient and which he would plant in future.
Mr Peck said they were really pleased by the response from the small group of interested graziers, growers, agronomists, and representatives from resellers, farm groups and seed companies who attended the free workshop.
He said their research trialled a wide range of sown pasture varieties in an open field situation on a private property that was periodically grazed by cattle.
"What this trial showed for those sowing a new paddock was which grasses to select and sow and which to steer clear of," he said.
Grazier Andrew Macarthur who runs Santa Gertrudis at Rock Point in Croftby, said the field day was "excellent".
Mr Macarthur said it was critical to learn about the newest research into the most and least tolerant grass varieties to combat pasture dieback.
He said after walking around the trial plots and listening to what Mr Peck and Mr Callanan had found during their four year trial he would be altering his pasture management plan.
"I thought the field day was excellent," he said.
"The work they had done astounded me actually because we have so many cross-sections of varieties and this was a properly statistically designed study."
Along with other participants Mr Macarthur was able to see first hand in the trial plots how each of the 29 grass varieties had fared when exposed to the pest.
He said on his non-irrigated land he had decided to avoid planting several species deemed highly susceptible including Bisset Creeping bluegrass and Premier digit.
"After this field day we will be changing our pasture plan to avoid varieties which are highly susceptible," he said.
"Now our management team will be meeting with Ted and Gavin, as well as Mark Lucas of Pasture Agronomy Services and our seed manufacturer as to what we will be doing with pasture from here on."
Mr Macarthur said he had a number of properties on the Scenic Rim near Kalfresh which would greatly benefit from his attending the field day.
"The other thing that really opened my eyes was how mealybugs had really devastated some of the species and really knocked them around," he said.
"At moment in our irrigated country we have a mixture of clovers, some lucerne, chicory ryegrass, prairie grass and fescue.
"I think a lot of graziers would have got a lot of out of this field day, I think it's one the industry's best kept secrets."
Mr Peck said pasture dieback was a condition that affected summer growing sown pastures and had been observed in the Fassifern Valley since 2017.
"Locally, pasture dieback has been widely reported in Rhodes grass varieties, panic grass varieties, kikuyu, paspalum, digit grass and creeping bluegrass," Mr Peck said.
"In 2020 we began a trial to test 29 grass varieties for tolerance to pasture dieback, including Buffel, Rhodes and panic grasses."
Mr Peck said in the January 2021/22 and January 2023/24 growing seasons, they applied high numbers of pasture mealybug to each variety and measured the effect on pasture health and biomass.
"We have trialled a wide range of sown pasture species in an open field situation that is periodically grazed by cattle and it's the only trial of its kind in Queensland which has been running for four growing seasons."
He said some pasture varieties could withstand a heavy mealybug load, while other varieties have really struggled and their plots have been colonised by other more tolerant varieties.
"And while we are getting damage in Rhodes grass, it is not yet apparent which varieties are less tolerant than the others," Mr Peck.
Mr Peck said pasture establishment was expensive and to sow, plough up and start again was complex.
He said one issue about beating pasture dieback in Buffle grass which was highly susceptible, was in Queensland there was more of this variety than all the others put together.
"In the districts which had Gayndah Buffel variety it tends to be so dominant it is close to being a monoculture," Mr Peck said.
"But the good news was in the trial some of the Buffle varieties look to be highly tolerant."
He said pasture dieback research continued through the Queensland Pasture Resilience Program, a partnership between DAF, Meat & Livestock Australia and the Australian government through the MLA Donor Company.
Mr Peck said more information about pasture dieback is available at FutureBeef or by calling 13 25 23.
Know more about this issue? Contact Alison Paterson on 0437 861 082.
