Friday, February 23, 2024

No surrender in decades-long war on weeds

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After decades on the frontlines, AgResearch’s Dr Trevor James is still waging a battle against the upstarts of the plant world.
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In this year’s Land Champions edition, we celebrate domestic and imported people in agriculture, from the Italian clan that owns a slice of North Otago wool production to the teacher rebooting ag education in the hort heartland if western Bay of Plenty.

Strategy, tactics, and planning are all skills useful for winning wars, and AgResearch’s Dr Trevor James has had a lifelong career using all three in waging a battle against the ongoing assaults of weeds on New Zealand’s environment.

The research agency’s senior scientist and well regarded “weeds guru” may have stepped back to four days a week at the Ruakura campus, but he remains no less committed to the fight. 

In a few short sentences he can rattle off encounters with almost all of the country’s most invasive, damaging and costly weeds capable of impacting the natural environment as much as the farmed one. 

Going back to the 1970s and ’80s, they include Johnson grass, spray-resistant fat hen, green cestrum, privet and woolly nightshade, to name a few.  

More recently James has helped identify and manage outbreaks of the likes of velvetleaf in maize and grain crops, yellow bristle grass through Waikato and Taranaki, and Johnson grass.

“One thing we have learnt is there is no such thing as a silver bullet when it comes to weeds. Weeds are weeds because they are tough and adaptable, and when it comes to dealing with them you have to treat it like a campaign. 

“And for a campaign you need to have a strategy, a budget and the energy, accepting it will take more than one season to deal with them,” he says.

Having grown up on a sheep farm near Coromandel, James has always had a strong affinity and connection with farmers. 

His ability to communicate with clarity and practicality with farmers has made him a popular choice at seminars and field days, and helping also to earn him the Plant Protection Medal this year, awarded by the Plant Protection Society.

He researches and publishes smaller pieces of research work on specific weeds like woolly nightshade or Noogoora burr weed that are easily understood and digested by farmers and growers. James says this has earned him a reputation of being more of a “farmers’ scientist” than a “scientists’ scientist” over the years.

“It’s just always been that I have felt the importance of our work lies with the farmers and growers most affected by any particular weed they had and needed to know more about.”

Improving farmer and growers’ understanding of weeds and their ability to identify them has also extended to James’s involvement in publishing NZ’s first definitive weeds digest, back in 1998.

Now approaching its fourth edition, it also incorporates many of his own photos, drawn from a keen interest in photography. Over the years he has developed a number of methods to better capture weeds on film, helping make them easier to identify in the field.

“It has really been a joy to take the photos, far easier than pets or children, and know that they are being used all over the country by the likes of farmers and regional councils.”

Some of James’s more memorable campaigns against weedy adversaries include identifying the country’s first outbreak of herbicide-resistant weeds in the late ’70s. Farmers had contacted him about patches of willow weed and fat hen in Waikato that were clearly no longer responding to herbicide treatment.

“We managed to isolate the farms and remove the weeds. We were too late to manage the fat hen but did manage to eliminate the willow weed.” 

He was also instrumental in leading the campaign against yellow bristle grass, an invasive, difficult to kill weed that raised its head in paddocks and along roadsides in Waikato in the early 2000s.

Intensive rounds of farmer information days culminated in him having a handy “ute guide” to the weed run through three editions, helping farmers in Waikato and Taranaki in particular get a handle on the aggressive weed.

James can also point to weeds once thought to be problematic that have bought some economic upside, particularly the likes of Kikuyu grass, which thrives in Northland and provides a valuable feed source on tougher country without necessarily outcompeting ryegrasses in all farm areas.

“And chicory has become a useful crop, while agronomists managed to get plantain to stand upright rather than spread out flat and it has become another feed option.” 

James is part of a generation whose career started when the internet was a fantasy, but he has come to welcome some of the latest tech that can help bring weeds into the spotlight sooner. 

That includes the iNaturalist NZ app, which can help identify weeds with a snapshot from a cell phone and then drawing on a pool of experts. 

“But I do worry that we risk only going in that direction and forget about old-fashioned methods of taxonomy and journeyman techniques.  A lot of that work needs to be done at the coal face with people, clients, councils, growers, and farmers.” 

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