Friday, July 1, 2022

No more thorns in our side

Vince from Tararua told Steve Wyn-Harris about his success with Vagrant Twitcher in dealing with thistles, both Californian and Scotch

Some weeks ago, I wrote about Californian thistles and the plague of them appearing here in increasing numbers over the past few years.

I usually get a bit of feedback from each column, but this one elicited a large number of emails, both from fellow sufferers and those with suggestions on how to deal with them.

I’ve never collated feedback from a column before but as much of this was useful and some of it lateral, I thought you might be interested.

Quite a lot had great faith in going down the chemical pathway.

Lex from Waimate is a huge fan of Versatill (Clopyralid). 

Tough on clover he tells me but deadly on thistles and the Calis. 

Years earlier he’d used it to spray a rape paddock covered in them and the control was the strip that was missed, which were the only thistles left. 

Now on a smaller block, he has eradicated them with some diligent spot spraying with his backpack. 

I’m going to offer him the pleasure of wandering around here with his trusty backpack for a few months.

John up in Northland had also eradicated his thistles with Versatill.

Another John from Whanganui had reliable results with Archer, which is also Clopyralid from using his weed wiper. 

But it needed a diligent approach with several applications. 

He was also a fan of Thistrol which is a bit of MCPA and MCPB.

Murray from Waimiha gave his Friesian bulls the flick and went back to good old breeding cows. 

His break feeding regime with these workhorses in the spring and early summer has seen his Californians disappear along with his rushes. 

Too late for me to change my farming systems but another often unseen advantage for the cow.

Nick down in Central Otago had the perfect organic solution.

He’s been farming in Central Otago for 40 years and until 10 years ago, calis, scotch and nodders were always a recurring problem. 

But he found an answer that cleaned them all out within two years. 

Something that quietly waits until the thistle seed head starts to flower and swell.

Something that loves plucking those colourful flowerheads off the plants, repeatedly leaving them with no means of reproducing. 

Thistles eventually give up. 


However, he can’t graze his goats in the sheep areas as they get full of worms but happily co-exist with his deer and there are no thistles in those paddocks.

Scobie who is well known from AgResearch wrote this thoughtful note.

“It seems there is one herbicide you have not tried on your Californian thistles. 

“It is effective. I worked alongside a scientist who spent his entire career looking for ways to control them and this is one of the few that works. 

“It is non-toxic and leaves no residue, will not contaminate waterways and there is no risk to your medical health.”

“There is a small risk to your mental health though. 

“I know you are a proud sheep and beef farmer and an advocate for trees. 

“The tried and proven way to get rid of Californian and nodding thistles is to graze them with goats.

“I shall be interested in your reaction. 

“I expect it to be the same as virtually every sheep and beef farmer I have ever talked to about goats. 

“Right now, ridiculous amounts are being paid for their fibre. 

“You can add ten goat’s percent to your ewe flock without reducing ewe numbers, rid yourself of weeds and simultaneously improve your pasture without putting diesel in a tractor – all scientifically proven, yet nobody seems to want to farm them. 

“I need to work out what that is about.”

However, there were also several fans of the biological control options which are appealing to me.

I’ve already seen the benefits of the Nodding Thistle Receptacle Weevil so know these biocontrol agents can be effective, free, and environmentally friendly.

The most enthusiastic was Vince, a dairy farmer from Tararua. 

He even supplied numerous photos of his small, imported friends.

His Green Thistle Beetle populations were having a decent impact on his Californians. 

The fact that intrigued me about these little critters was that they protect themselves from predators by piling their own excrement upon their backs.

Vince, who obviously has a sharp eye and is observant, had also imported the brilliantly named Vagrant Twitcher which was happily chewing away on his Scotch Thistles as well.

The insects weren’t eradicating his thistles but were definitely helping with the control.

I’m going to visit Vince in the spring to harvest some of his helpful insects and bring them here. 

Not just to assist in thistle control but because of the ways in which they protect themselves needs to be seen and because their names are so cool.

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