Farmers fear swarming locusts

Australian plague locusts are moving in swarms in the Great Southern and the Wheatbelt, sparking fears the insects could destroy crops in the growing season.

Department of Agriculture and Food Albany entomologist Mike Grimm said locusts were moving in groups of up to 2500 per square metre in some areas.

"We've got a hotspot of locusts between Jerramungup and Ravensthorpe and we are also getting reports of locusts more widely through Wheatbelt areas, including Hyden, Southern Cross, Marvel Loch and further north at Pingrup," he said.

"We are now looking at 130,000 hectares that have got locusts and some patches with quite high numbers."

Mr Grimm said locust numbers ranged from 20/sqm up to 2500/sqm.

The insects have put a significant dent in green feed supplies in the Great Southern, where some farmers have had to shift stock from paddocks.

Ravensthorpe farmer Chris Biddulph said locusts chewed through about 25 per cent of his green feed and most of his lucerne paddocks.

"They have taken the leaf off about 70ha of lucerne," he said.

"In one patch we came across a band 1.2km long and 2m wide zig-zagging across the paddock - there would have been at least 500/sqm.

"Behind them the paddock was golden but in front of them it was still green."

Mr Biddulph sprayed about 600ha of his 2640ha farm to control the pests, which added about $1800 to his spraying costs.

His flock of 4000 sheep had to be shifted from paddocks because of spray residue.

Mr Biddulph said he would have to resort to other measures to fatten lambs after his lucerne crop was almost wiped out.

"The lambs were going in there after they finished the cereal stubbles but we'll probably have to top them up with a bit of grain," he said.

Mr Biddulph said locusts originally moved in late last year and had entered their second hatching a fortnight ago.

He said the insects had laid significant numbers of eggs around the property and an early break could cause grave problems after seeding.

"The problem is if they hatch at seeding time," he said.

"Our canola and lupins are especially high risk because once they are chewed they do not regenerate."

The Biddulphs have received 364mm of rain since October which have created a 'green bridge' for the insects to thrive.

Farmers are concerned about locust activity if there is an early break to the season because it will still be warm enough for the insects to hatch.

Mr Grimm said locusts went into dormancy over the cold months and hatched when temperatures increased.

He said warm weather at harvest could be disastrous in locust hotspots.

"There is a real possibility of locusts emerging as the crops are finishing and that is going to give the risk for damage," he said.

Mr Grimm said the department was no longer in charge of spraying for locusts and since 2006 had taken on more of a monitoring role.

Several farmers have criticised the department's approach to locust control, arguing that the issue should be treated as a State problem.

Cascade farmer Wayne Walter had significant locust numbers on his property a fortnight ago.

He said he did not spray because he backed a blanket, rather than individual, approach to the issue.

"There is no point in taking an individual approach because they will just move to the next paddock," he said.

"Years ago the department used to spray but now they just monitor for them and don't do anything."

The department is planning further monitoring in about a month.