Where are the new herbicides?

Abstract

Herbicide resistance has become one of the foremost problems in crop production worldwide. New herbicides are required to manage weeds that have evolved resistance to the existing herbicides. However, relatively few herbicides with new modes of action (MOAs) have been discovered in the past two decades. Therefore, the discovery of new herbicides (i.e., new chemical classes or MOAs) remains a primary but ongoing strategy to overcome herbicide resistance and ensure crop production. In this mini‐review, starting with the inherent characteristics of the target proteins and the inhibitor structures, we propose two strategies for the rational design of new herbicides and one computational method for the risk evaluation of target mutation‐conferred herbicide resistance. The information presented here may improve the utilization of known targets and inspire the discovery of herbicides with new targets. We believe that these strategies may trigger the sustainable development of herbicides in the future. © 2021 Society of Chemical Industry

The potential future roles of natural compounds and microbial bioherbicides in weed management in crops

“…Herbicides with new herbicide modes of action are in great demand because of the evolution of weed resistance to herbicides from almost all mode of action classes (Heap, Duke, 2018;Gaines et al, 2020) and the lack of commercial herbicides with new modes of action over the last 30 years (Duke, 2012;Qu et al, 2021). Therefore, herbicides with new molecular targets are needed for herbicide resistance evolution of target site resistance more improbable, a trait that no commercial herbicides have (Gressel, 2020).…”

“…This technology is showing its age with the ever growing evolution of resistance to available commercial herbicides and even resistance by non-target site mechanisms of resistance to herbicides yet to be introduced (Gaines et al, 2020). The number of herbicides being introduced with new molecular targets and/or new chemical classes for which no resistance exists is few (Qu et al, 2021). Natural products have been the inspiration for insecticides and fungicides with new molecular targets, but to a much lesser extent with herbicides (Lorsbach et al, 2019;Sparks, Duke, 2021).…”

Success, despite another plague year

“…Three papers were from the In Focus section on herbicide mode of action and evolution of resistance 44–46 . One of these papers was on new approaches to finding new herbicide modes of action, 45 and a paper in another issue discusses paucity of new herbicide modes of action and the prospects for the situation changing 47 . Haywood et al .…”

Hierarchical cluster analysis of herbicide modes of action reveals distinct classes of multiple resistance in weeds

“…By contrast, multiple-resistance arises through more than one mechanism, such as combination of both target-site gene mutation and metabolism-based resistance conferring resistance to different herbicide MoAs. 13 The problem of weed species becoming resistant to multiple herbicide MoAs is only likely to get worse because few novel herbicide MoAs have been commercialized in the last two decades [14][15][16] forcing farmers to rely on an ever more limited range of agrochemical options. It has been argued that increasing rates of resistance to multiple herbicide MoAs over the next 50 years may render existing herbicide MoAs obsolete for many cropping systems.…”