Report of Wheel Cactus Treatment at Oratunga, September 2020

By Ralph Abbot OAM


In June 2011 a group, organised via the Overland 4WD Club, spent a week treating wheel cactus in Oratunga Station on the Glass Gorge Road, west of Blinman.

Each year since a group has spent a week at Oratunga cacti killing. Statistics for previous years up to current are tabulated below.


The coronavirus COVID19 in 2020 caused the cancellation or postponement of many activities throughout Australia and the rest of the World. Our Overland 4WD Club Oratunga cactus cull 2020 was originally planned for Monday     August 24 to Saturday August 29, but the Toyota Club’s Gum Creek cactus cull was postponed from May and rescheduled to August 19-26, both Wednesdays. That meant we could not start until after Wed 26th August so we    rescheduled to Monday 31 Aug to Saturday 5 September with no lay day.

With overseas trips cancelled a number asked if they could come to Oratunga. There were two booking systems. Many contacted Ralph (as normal) asking if they could come. But also there was a list at Overland Club.  Usually the      numbers from the Club are small. Now many Overland Club meetings were cancelled because of covid19. When those meetings resumed there was quite a list of Overland Club members who already had their names down – 12 in fact.

So then we had a list of 30 who were planning to go to Oratunga. Gini was mortified. Too many for the infrastructure to support. At the time covid19 rules allowed up to 50. But not long before the start the limit was reduced to 10. Despite contact with the covid19 authorities and advising that we would have three teams of 10 separated at the house, the shearer’s quarters 400 m away, and with camping trailers in Glass Gorge, some km away, the rule was still 10 only. Plus Gini, the occupier. So it was decided that only Overland Club members would be allowed. Ralph then had to ask one Overland couple (who would be cactus killing the week before at Gum Creek) to not come to Oratunga. That made 10 who were going.

A few days before the start, the limit was raised back to 50 again. It was too late to contact everyone.

I had earlier asked Brian Jenkins if he would lead a team spreading cochineal along the Mt Samuel track. A few days before the start Brian and Katie contacted Gini and asked if they could come. Since the limit was then back to 50, Gini said they could. Later Katie phoned Tim and Maggie who then decided they would come too on their way back from further north.

So we finally had 14 in attendance. Plus Gini.


Many thanks to those who have forwarded photos. And especially Maria for those of the survey mark in Artimore PAR.

The team organisation

The team split into two with one team (Flat Earth) searching for cacti around the Oratunga house and the other (Cochineal) spreading cochineal along the Mt Samuel Track. These are separately reported below.

Diary and results

Monday 31st August 2020

Finally the operation got under way. It was decided that, to start  operations, all would search the mountains north of the Oratunga house. Several years earlier there were plenty of cacti on the first mountain. It was also of interest how far north the infestation went. The previous year there were no cacti in Oratunga Creek which flows east-west north of the Moolooloo fence, suggesting the northern limit was south of the Oratunga Creek.

On the first day two teams of five were formed. Team A searched   N-S between lanes E 275300 – 275400 going north and E 275200 to 275300 return. Team B worked adjacent lanes, E 275100 to 275200 out and 275100 to 275000 return. Both started at northing 6560900 N which is at the base of the mountain close and north of the house. The day saw the two teams struggling to climb the steep shaly mountains often covered in calitris trees. Cacti were found on the first mountain north of the Oratunga house but nothing further north. At the northern limit of the search (N 6562550) one could see a long way in the bare valley to the north and no signs of cacti further north possibly as far as the Moolooloo fence.

With the cacti found being mainly on the face of the mountain behind the house it is possible that crows that occupy the trees on the mountain north of the house hang around the house because of activity and possible food. Hence the cacti spread by the crows are located close to the house.

Tuesday 1st September 2020

On Tuesday the teams went in two different directions. A cochineal team was formed with Brian, Katie, Tim, Maggie and Bruce. The work of the cochineal team will be reported later in this report.

The rest of the group formed two teams called the Flat Earth teams. These searched south of the Glass Gorge Rd where cacti had been seen in earlier years. A few cacti were found and treated.

Wednesday 2nd September 2020

On Wednesday it was decided by the Flat Earth teams to have a day off following the very hard Monday. A drive along the Artimore PAR was taken. The group travelled east from Oratunga past Blinman and Angorichina then turned left towards Narrina then left onto the Artimore PAR. Part way along the PAR the group stopped to inspect a survey marker beside the track. It bore the number 6635 1029. Around the survey marker was a number of flat galvanised sheet metal disks about 200mm dia in no discernible pattern, nailed into the ground.  The photo shows two of the disks with the folded-under straps. Surveyors Alexander  Symonds, Survey Consultants in Kent Town, were contacted to try to ascertain the function of the discs. Brenton Carn from there responded with, “We are reasonably sure that they were used to hold down a photogrammetry target for mapping purposes. The target itself has disintegrated (likely made of plastic) and the nails and plates have been left behind.”  That response was provided to Brenton by Marc Blundell, Geodetic Surveyor in the Attorney-General’s Dept.

The survey mark was created in 1964 as part of a 1:50,000 aerial survey.

The plot on the map below shows the travel along the Artimore PAR but the track recorder was not started until part way along the Artimore track.

On Wednesday night the group dined in the Blinman Hotel.

Thursday 3rd September 2020

On Thursday it was planned to have the Flat Earth teams search the area well to the east of the Oratunga House, an area we had never searched before. Gini indicated the track which would give vehicle access close to the area. We drove the track and then set to the search. There is a 729 m high mountain that can be seen near the top of the map alongside of the tracks. The side of that mountain was steep with shale and calitris forest. It made the climbing difficult. It is the highest mountain for some distance. It  is 5 m higher than Mt Elkington. The closest higher mountains  are 15 km W, Mt Samuel at 791 m, 8 km SW unnamed peak    739 m and 8 km NW Mt Lucius at 815 m. They are the nearest taller peaks. It was hardly the mountain for Tim, Michele and Ralph, of the Flat Earth team, to scale!

On the return leg several cacti were located, mostly by following a creek rather than searching the set lane.

Friday, 4th September 2020

On Friday the Flat Earth teams continued the search south of the Glass Gorge road, moving further westward, closer to the entrance to the Glass Gorge.

The Cochineal Team

Tuesday 1st September

The Cochineal Team comprised Brian, Katie, Bruce, Tim, and Maggie.

Legend: In the plots

Red = clean cactus, either removed or treated with glyphosate.

Green = Already infected with cochineal so no treatment.

Blue = Seeded with cochineal

On Tuesday Tim’s and Maggie’s vehicle was left at the gate to Mt Samuel Track. The group in Bruce’s vehicle checked along Mt Samuel Track the areas that were previously cochineal infected. They collected cochineal from the Lindow Bore nursery and spread it further north. Bruce kept walking back to his vehicle to drive it forward to where they had walked as his vehicle       contained the cochineal.

When the day was done Maggie, Katie and Brian walked out to the Warra Warra Spring while Bruce drove out then Tim drove his vehicle out from near the Mt Samuel Track gate.

Wednesday 2nd September

On Wednesday the cochineal team parked in Glass Gorge and climbed the ridge to the patch that was treated last year. They found the poisoning from last year was very       effective and reported that two clusters that had been seeded with cochineal were heavily infested. They also found several small plants that cochineal had spread onto. They continued on a loop that crossed the     Breakneck Well gorge track and poisoned  the plants they encountered.

Thursday 3rd September

On Thursday morning the group returned to the Glass Gorge ridge patch that they visited the day before to harvest cochineal. They filled a tub and some buckets with cochineal infected pads. Most of that was stashed away in Glass Gorge for use on Friday. They travelled in vehicles along Glass Gorge Road attending to cacti spotted on previous days. More cacti were found near First Spring. Near the end of the day they treated several cacti opposite Warra Warra Spring. Brian explored up a creek and found a “monster”.

Friday 4th September 2020

On Friday the group returned to Mt Samuel Track with the stashed cochineal. Maggie and Tim walked in from Warra Warra Spring and seeded cochineal on plants found. Barbara joined the group as a driver which allowed Bruce to be fully active. Barb had lunches and extra water and moved the vehicle along Mt Samuel Track to meet the team and restock. At one stage Tim and Brian walked further north to the next creek and seeded the cacti they found. They saved the last cochinealed pads for the “monster” Brian found the day before. On the way out with both vehicles some more cacti were spotted near the grid at Kirbin Well.

Some cochineal was spread on them until it ran out so it is recommended that that area be checked next year.

Waypoint in Kirbin Well (3 plants) – report of more cacti in the creek to the south of the waypoint that are all good for cochineal.

Saturday 5th September 2020

On Saturday most drove home to Adelaide. Gear was dropped off at Alpana and Gum Creek en route. Several went via Parnaroo near Peterborough to inspect the cactus infestation there that Bruce proposes to organise a club trip to help treat it.

Oratunga Score Card 2020

The table below shows the numbers of plants treated each day. Large plants are those treated in location. Small plants are those that are difficult to inject because they are small and soft. They were placed in a bucket and taken back to camp for disposal. Hours are recorded as 7 hours per day per volunteer. That includes travel from Adelaide to Oratunga and return which also averages 7 hours per day.


Gini and I thank you all for the effort you have put into dealing with cactus and assisting around Oratunga. It has been a great team effort.