THE CATERPILLARS are coming.As reported in The Courier on Saturday, a plague of the insect has invaded properties in the Ross Creek and Haddon area. But more reports of the caterpillars in big numbers have emerged from across the Ballarat district.Tracy Howard said caterpillars had appeared overnight at her 42-acre Blampied property in early September.Since then they had taken over. "There's just so many of them. All you see is just yellow everywhere," Ms Howard said. She said she had first noticed the caterpillars in the spring two years ago."This year has been the worst year though."One reader said she had discovered caterpillars in "plague proportions" when she took her dog for a walk at grasslands near Ring Rd, Wendouree."There were caterpillars everywhere, to the extent I picked up my little Chihuahua as I didn't know if they stung or would have any effect on her treading on them." Department of Primary Industries spokesman Chris Bluett said he could not recall an infestation of hairy-bodied caterpillars in such proportions in 20 years in Ballarat. He said there was no clear pattern in the insect's behaviour in the limited reports received by the department.In some areas they were stripping paddocks bare in lines, in others they were scattered evenly in the grass.The department hopes to determine exactly what type of caterpillar it is soon.Samples of the insects have been sent to an entomologist to establish a positive identification, he said."There's a few theories around as to what they are, all of which are plausible and it probably is one of them but we're not too sure which yet until we have had a look at it."He said the plague could have been caused by a flight of moths into an area on a wind which had then laid eggs. "(But) you've got to have the right sort of conditions, whatever those conditions might happen to be."