Peter Newman explains what's going on in this interesting research.
They said it couldn’t be done - climbing Everest, flying to the moon and even deep-frying Mars bars. We were also told that we couldn’t reverse herbicide resistance. In the majority of cases, the experts are right - herbicide resistance is permanent, and we thought that was the case for all resistant weeds.
Until now…
AHRI researchers, Dr Roberto Busi and Dr Danica Goggin have seen trifluralin resistance disappear in two populations of ryegrass that they were studying. They started with trifluralin resistant ryegrass then they “bred” prosulfocarb resistance using recurrent selection over several generations, and as the ryegrass became more prosulfocarb resistant, it became susceptible to trifluralin. This is called negative cross-resistance, and it’s extremely rare.
The researchers suspect that this is due to the P450 enzymes involved in metabolic resistance and more research will confirm this.
What do we do with this information? Should we try and reverse trifluralin resistance in the field by evolving prosulfocarb resistance, or are we better to simply mix trifluralin with prosulfocarb and other pre-emergent herbicides to maximise efficacy and slow the evolution of resistance?
Some of the great discoveries in science are accidental, just as Alexander Fleming discovered penicillin and changed medicine forever, Roberto Busi accidentally discovered reversing trifluralin resistance. It remains to be seen whether this changes herbicide resistance forever!