BIOTECHNOLOGY gave the cotton industry a new lease of life – or more accurately, allowed the industry to survive – but the age of miracles is over, Moree consultant Andrew Parkes told the Australian Cotton Conference.
Mr Parkes, chairman of the Transgenic and Insecticide Management Strategies Committee, sounded a clear warning about the dangers of heliothis resistance to Bt (Bacillus thuringiensis) gene technology.
Transgenic cotton carrying the Bt proteins allowed the industry to vault over mounting concern about pesticide use in cotton.
But now the conditions for fostering resistance to the proteins used in transgenic cotton are widespread, and there are disturbing signs the industry won’t be able to make a clean start when Bollgard III is released in about six years.
The native heliothis moths whose larvae wreak havoc on cotton have shown a prodigious ability to acquire resistance to everything thrown at them.
Mr Parkes said traits for herbicide tolerance and insect resistance were now present in 90-100 per cent of the cotton crop.
“Not only are we increasing the percentage of the traits we are using, we are also massively increasing the area of cotton using these traits, in the past two years in particular,” he said.
“In terms of exposure, not only do we have these proteins out there 24/7, we have them on almost every hectare we sow.”
Compliance is also an issue. Monsanto’s compliance auditing shows 4-8pc of transgenic cotton licence holders fail to comply with resistance-related practices.
“With the recent growth in hectares planted to Bt cotton, this translates to a more than five-fold increase in non-compliant areas planted to cotton in the past two years.”
At the end of July 2012, there had been more than a sevenfold increase in non-compliance with mid-season practices like pupae busting.
Mr Parkes said this could reflect issues with the season, and in the past mid-season non-compliance had been corrected by planting, but he still regarded it as a worrying trend.
New research is also highlighting Bollgard III will not wipe the resistance slate clean.
Bollgard III stacks the Cry1Ac and Cry2Ab present in Bollgard II with the Vip3A protein, discovered by Syngenta – reportedly in milk soured in a research lab fridge – and licenced to Monsanto.
When Cry1Ac was released, there was about 1:1,000,000 chance it would be eaten by a heliothis with a background resistance to the protein.
With Cry2Ab, the odds shortened to 1:100, but the two proteins work in concert in Bollgard II.
Now Australian scientists have found the odds of background heliothis resistance to Vip3A is 2:100 or 3:100 – “and once they are resistant, they are highly resistant”, Mr Parkes said.
However, as the research paper identifying the background resistance noted, “fortunately the resistance is largely, if not completely, recessive and does not confer resistance to the Bt toxins Cry1Ac or Cry2Ab already deployed in cotton crops”.
Mr Parkes also entered a plea for greater attention to herbicide resistance in cotton and the grain crops that are often sown on the same land.
“Do we have to follow America in everything?
“50pc of upland American cotton is infested with glyphosate-resistant Palmer amaranth.
“Prior to 2005, 17pc of the growers in Georgia were hand-weeding 50 per cent of their area, at a cost of $2 an acre.”
“Seven years later, they are hand-weeding 52pc of the area, and it’s costing them $24/ac.
“In 2011 there were 13 recorded species resistant to glyphosate in the US, within which there were 85 biotypes in 28 States, of which 15pc were resistant to more than one mode of action.
“If we don’t focus on what happens in the long term we won’t have an industry."
