THERE'S a great irony to Professor Stephen Powles' oft-quoted saying, when you're on a good thing, don't stick to it.
It's because the Australian Herbicide Resistance Initiative (AHRI) director and UWA Professor has stuck with agriculture all his life, bar two years working for the NSW public service when he was 15.
"I'm a happy man," he said. "I love my job mixing the science with the practicalities of making it work for farmers."
And AHRI is his crowning glory, gaining world recognition as a centre for research excellence into herbicide resistance in crops and weeds. Resistant weeds have been a curse on the Australian grain belt since the first samples of ryegrass and barley grass were identified as being resistant to Hoegrass in 1983.
Stephen also has become a world leader in the field and is a popular pick as a speaker at many Australian and international conferences.
But he still regards his now famous saying as the most sensible sentence he has ever uttered.
"When on a good thing don't stick to it popped into my brain in 1990 when I was speaking to farmers about the necessity to rotate herbicides even when one particular herbicide worked really well," he said. "That was the problem, because logically, if it worked and killed weeds and grasses, it should be earmarked for all spraying applications.
"My point was that sticking with the one good thing was the pathway to weeds and grasses becoming resistant to the good herbicide.
"It was a play on words of a famous commercial relating to the benefits of a fly spray, with a punch line, when you're on a good thing, stick to it.
"My saying, about not sticking to it, resonated with farmers and many others and led to a better understanding of how they could diversify practices to reduce weed seed burdens and at the same time, reduce the incidence of resistant plants."
Work continues on herbicide resistance with a team of 15 scientists working at the GRDC-funded AHRI, working in collaboration with the Department of Agriculture and Food, University of Melbourne and the Queensland Department of Primary Industries and others, to encourage the delivery of consistent resistance management messages.
The main message continues to focus on rotating herbicides and incorporating non chemical tools such as harvest weed seed control practices, because there is no magic bullet to kill weeds.
In WA, resistance continues to plague farmers in the face of a diminishing supply of effective chemicals.
"Many of the Group A and B chemicals don't work anymore," Stephen said. "And there's pressure on, and increasing resistance, to trifluralin, glyphosate, 2,4-D and atrazine.
"It's pleasantly puzzling why atrazine and simazine continue to work but we all realise that wild radish is evolving resistance throughout the Wheatbelt, particularly in the north."
But Stephen has his own issues as a central Wheatbelt farmer which has become a passion and a relief valve from the pressures of the scientific world.
He has an all-crop enterprise at Quairading of 600 hectares (1500ac) which is share-farmed with good friends and neighbours, Shauna Stone and her son Kent.
"Through the years I have been close to the farming community and count many farmers throughout the Wheatbelt as my friends," Stephen said. "I wanted to have some land but could only recently afford it and thus in 2007 an opportunity came up for me to buy the 600ha in Quairading and it has worked out perfectly with the Stones' involvement."
When he first saw the block, Stephen's keen eye assessed it as being in reasonable shape with a mixed enterprise history, which included no-till crop establishment.
It was weedy and yes, resistance was rife.
But with the skills of the Stones, diverse, integrated control strategies, a successful continuous cropping regime has been established comprising wheat, barley and canola.
And faithfully following his famous line, Stephen and the Stones rotate glyphosate with paraquat for knockdowns and trifluralin, Boxer Gold and Sakura for pre-emergent spraying.
"We never cut rates and we use about 80 litres a hectare of water," Stephen said.
"To target weed seeds, we drop chaff on tramlines, as we don't burn windrows anymore.
"Dropping chaff on windrows provides a hostile environment for weed seeds and infrequently there may need to be a nozzle spray application to knock out any germinations."
Stephen's inquiring mind always takes him back to the drawing board to mull over possibilities for improving strategies to combat weed seed populations.
But there's one line that never gets rubbed off the board.
You know the one. When on a good thing don't stick to it.
Stephen's "ah ha" moment regarding resistance came in the early 1980s, during a review of his academic career which started at Hawkesbury Ag College, NSW, where he graduated in ag science.
He achieved a Masters in Agricultural Science at Michigan State University, returned to Australia and graduated with a PhD in plant physiology and biochemistry at the Australian National University, before returning to the US to complete a post doctorate at Stanford University, California with further studies in France.
"I woke up one day and realised my research was becoming increasingly fundamental," Stephen said. "It was only of interest to a few researchers and I wanted to get back into agriculture.
"I had become aware of the first cases in the world of herbicide resistance occurring in the US and France.
"And I thought the same thing might be occurring in Australia and I wanted to look for it."
A bold application for a research grant to pay his salary, saw him win funds from the Reserve Bank and in 1983 he returned to Australia to work at the Waite Agricultural Institute, South Australia.
With eyes attuned to a new problem, he saw ryegrass and barley grass resistance to Group A chemical Hoegrass.
"I started working on it and within a short space of time, the problem exploded throughout Australia.
"I had all the knowledge and in hindsight, my decision to follow an education pathway was vindicated.
"I built a big research team at Waite and it became the world's biggest research centre on herbicide resistance."
WA eyes followed Stephen's work and with a major resistance issue ballooning in WA in the 1990s, a collaborative effort by GRDC, UWA and DAFWA, saw Stephen offered the opportunity to establish the WA Herbicide Resistance Initiative (WAHRI).
In 2010, WAHRI became AHRI with a national focus.
And he is just as excited now as he was when he experienced his light bulb moment in Europe 30 years ago.
His career has seen him move from tractors to test tubes to taming the testosterone of weeds and grasses.
As with everything in agriculture, he has learnt that you move cautiously and methodically in the shadow of Mother Nature.
