13th February, 2018: First it was virus; and now
it comes to the weeds! In a shocking discovery, the researchers of University
of Sheffield, UK have found that herbicides are progressively becoming incapable
of controlling weeds as the plants have evolved resistance against them.
Researchers also warn of a serious threat to global food security on account of
this development and calls for developing new strategies of weed control with
reduced reliance on chemicals. The results are published in Nature Ecology &
Scientists have mapped the density of black-grass populations across 70 farms in England, collecting seed from 132 fields. They also analyzed the historical management data for all fields to find out what drives the abundance of black-grass abundance and how do they develop herbicide-resistance.
“We found that the extent of herbicide resistance was primarily dictated by the historical intensity of herbicide use, and that no other management factors had been successful in modifying this resistance risk,” said Paul Neve, a weed biologist and leader of Rothamsted’s strategic programme, Smart Crop Protection and a co-author of the study.
On surveying farmers, the research team also found that the increased weed densities lead to higher herbicide costs and lower crop yields, resulting in significant losses of profit. They also found that Increasing resistance is linked to the number of herbicide applications, and mixing different chemicals or applying them cyclically did not prevent resistance developing.
The researchers recommend that farmers switch to weed-management strategies that rely less on herbicides, as it is inevitable that weeds will overcome even new agents.