Italian ray-grass is a common grass in arable cultures
John Cussans
The herbicide glyphosate-resistant weeds were found in the United Kingdom for the first time. The species in question, called Italian Rygrass, is widespread in the United Kingdom, but specimens impermeable to the chemical product were only found on a Kent farm.
Glyphosate has helped farmers adopt agricultural practices more respectful of the environment known as regenerative agriculture, said John CussansAn expert in weeds management at the Adas consulting firm. His team confirmed that plants were test resistant in a greenhouse.
“This can affect our ability to make the transition from our agricultural system,” explains Cussans. “Resistance to glyphosate herbicides is a very important practical problem in a farm.”
In the United Kingdom, farmers use glyphosate mainly to clean all plants in a field before planting seeds. This allows them to avoid plowing, which damages soil health, increases erosion and reduces carbon storage.
The minimization of soil disturbances is one of the key plates in regenerative agriculture, as well as the rotation of crops and the maintenance of the ground cover.
“Glyphosate is relatively benign for the environment in relation to other agrochemicals,” says Helen Metcalfe In Rothamsted Research in Harpenden, United Kingdom. “It shows very little bioaccumulation and low toxicity. And it supports regenerative practices such as minimum soil work, which is really ideal for soil health. It may actually have environmental advantages compared to some of the alternatives. ”
Weeds are a massive problem for farmers, says Paul Neve At the University of Copenhagen in Denmark. “We lose more crop yields with weeds than insects with pests and pathogens.”
All over the world, at least 56 species of weeds, including Italian Ray-Grass (Pitrino) have evolved resistance to glyphosate, and this has occurred independently in hundreds of different places. These weeds are a major problem for many farmers in the United States and Argentina, where cultures developed so as not to be affected by glyphosate have been cultivated on a large scale for many years.
“But in fact, since the first case was 30 years ago, it did not explode in a huge problem,” said Neve.
This is a big problem on individual farms where resistant weeds are present, explains Neve, but weeds spread more slowly than, say, harmful insect insects. Taking precautions such as cleaning agricultural equipment to get rid of any seed can slow their spread.
Farmers must also adopt a range of weed control measures and not only count on glyphosate, explains Metcalfe. “We have found that if farmers focus on controlling weeds and implement all these alternatives to glyphosate, it is possible that the profits are starting to recover after five to 10 years,” she said.
The Cussans team intensified surveillance in the United Kingdom in 2018, testing more than 300 Italian Ryegrs samples. He thinks that the resistant plants of the farm in Kent have certainly evolved in situ, rather than being brought elsewhere.
He also thinks that the fact that resistance seems to have taken much more time to evolve in the United Kingdom than in other countries, because farmers do not cultivate genetically modified or raised conventionally to be resistant to glyphosate. With such cultures, glyphosate can be applied to control weeds while crops increase as well as before seed planting.
