Weeds pose the greatest risk of crop loss for wheat and barley farmers, but the increased use of herbicides to kill these weeds has meant that certain species are now resistant to herbicide chemicals.
Researchers in New Zealand have assessed the risk of herbicide resistance in 101 weed species known to affect wheat and barley crops on Kiwi farms.
While most species (55) were considered to be low-risk of developing resistance, 30 were medium-risk, and 16 were considered high-risk.
Herbicides containing acetolactate synthase inhibitors were found to pose the greatest risk of causing resistance for more species than other kinds of weed killers.
The researchers conclude that NZ farmers should be informed about the high-risk weed and herbicide combinations to avoid future crop loss.