Insect use impacting on cactus issue

The efforts of Roger Christopherson, from Stirling North, volunteers and the Quorn Community Landcare Group working in the Flinders Ranges over the past five years are paying great dividends.

Good seasonal conditions for cactus has resulted in widespread growth and germination of cactus on farm and grazing land.

A particular problem is Engelmanns Pear – a large padded cactus with long sharp spines.

Cochineal is a form of scale  insect  which  sucks  sap  from  several  cactus  species.

Different strains or species of the insect require specific host cactus to live on.

Andrea Tschirner from the Quorn Community Landcare Group has been breeding cochineal insects in boxes in her shed for the last three years.

“Around Quorn we now have a very effective strain of cochineal, but we know very little about its identification,” she said.

“Due to the size and nature of the insect, they are extremely difficult to properly identify.”

A small sample of Quorn cochineal recently made a big trip to the city.

Entomologists  from  South  Australian  Research  and  Development  Institute  (SARDI) are hoping to support Quorn Landcare volunteers to better identify which insects are working in their region.

Andrea says “with this knowledge we will be able to help other areas experiencing big problems with cactus”.

“Graziers around Peterborough are having a significant problem and we have also been approached by farmers  in  Western  Australia who are finding cactus spreading into their cropping paddocks,” she said.

Retired roo shooter Roger Christopherson first noticed cactus growing in remote paddocks around Port Augusta many years ago.

His observations and enquiring mind led to collecting and trialling different biological controls in his Stirling North home.

Something that started as a project with boxes, tubs and tongs in a shed is now gathering interest and support from researchers and farmers interstate.