Pastures under insect attack

The damage cockchafers can do to a sporting oval.

GIPPSLAND farmers already enduring a tough season are now facing the threat of insect attack on autumn pastures.
Crickets, red-headed cockchafers and the Argentine stem weevil have been identified in various parts of the region in recent weeks.
South Gippsland farms on the flat lands around Leongatha South are reporting cricket infestations, while red-headed cockchafers have reappeared in West Gippsland and the Argentine stem weevil is affecting pastures in East Gippsland and around Yarram.
Department of Economic Development, Jobs, Transport and Resources dairy extension officer Greg O’Brien said the cricket problem in the south of the region was connected to the dry conditions.
“They live in the cracking soils where they have a good habitat to breed,” he said.
“At this time of year, they come out and eat seed that is sown into paddocks. You get poor establishment if they are there in significant numbers.”
Greg recommended talking to an agronomist or chemical rep to look at options for controlling cricket numbers before autumn sowing.
The Argentine stem weevil has been reported around Orbost, in the Macalister irrigation District and around Yarram.
The insect larvae, which eat rye grass stems from the inside, can be hard to detect to the untrained eye.
Murray Goulburn agronomist Gavan Lamb said a recent case in the MID had highlighted the problems that could be caused by the weevil.
A farmer had contacted him about a rye grass paddock that had been sown out two years ago but had failed and only grown clover.
A visiting New Zealand agronomist was with him at the time and quickly identified it as the South American pest.
“Apparently, it’s not new, it just hasn’t been recognised,” Gavan said.
“It’s starting to suggest that certain varieties are prone to Argentine stem weevil, so making good decisions about autumn sowing and which varieties you will put in becomes even more important.
“Selecting the right endophytes – which is the insect resistance built into some varieties – is the crucial thing.”
Gavan said speaking to an agronomist was the best option if farmers suspected the weevil had infested their rye grass plantings.
In West Gippsland, Longwarry dairy farmer Wayne Weller has once again been infested with red-headed cockchafers.
The pasture pest, which has been estimated to cost an average of $115,500 per annum for affected farmers, kills rye grass plants by eating their roots.
Identifying areas of infestation can be difficult, with the red-headed cockchafer larvae remaining underground while they feast on the plants.
“You can see small patches and you know they are there. But you may have more than you realise,” Wayne said.
“If you have paddocks that don’t green up in the autumn break, then it might be an idea to have a good look.
“Pull some of the dead, dry grass out and see what is underneath. If they are there, it will pull out a bit like carpet because they’ve eaten the roots out underneath.”
Another good pointer to red-headed cockchafer infestation is the prevalence of birds in paddocks at this time of year.
“If you see a flock of crows in the paddock scratching around, then nine out of 10 times there will be cockchafers,” Wayne said.
Having battled the pest for around 14 years, Wayne said there was little that could be done other than cultivating the affected land.
GippsDairy projects and events co-ordinator Karen Romano said insect pests were a major issue for Gippsland farmers, with further research needed to be done into improved control methods.
“GippsDairy has led a major project in recent years in tackling the red- headed cockchafer problem, with promising results coming out of the research,” she said.
“Insect infestation is a major issue that costs the industry millions of dollars each year, so we would urge farmers to be vigilant about potential pests in their pastures and talk to experts for help in controlling them.”
GippsDairy has produced a cockchafer identification guide which shows the red-headed and black-headed cockchafers in adult and larval stages, while also identifying the similarly destructive African black beetle.
For a copy of the booklet email GippsDairy at executiveassistant@gippsdairy.com.au or call 5624 3900.