General Articles

Herbicide Resistant Weeds: Plague of the 21st Century

The science of developing new active substances to use in herbicides and other crop protection products is more demanding than ever. Not only have our standards for safety and environmental protection improved, but it’s also vitally important for scientists to understand exactly how each chemical works on the molecular level.

The reason? Herbicide resistant weeds. Having a thorough understanding of a specific herbicide’s mode of action is essential in order to control resistant weeds and to prevent resistance in the first place. A weed that spontaneously develops resistance to “mode of action A” is very unlikely to also have spontaneously developed resistance to “mode of action B”. Thus, rotation among different herbicides with different modes and sites of action is an important part of any farmer’s weed management plan.

How research scientists are fighting herbicide resistance

In order to provide a growing global population with safe, healthy food, we need a variety of different types of herbicides that are both effective and have no negative effects on people, animals or the environment. Many companies in the agricultural industry have worked hard over the past several decades to replace older herbicide chemicals with new products that are much safer, practically nontoxic and effective at lower doses. And these research scientists are also discovering new targets in weed plants that could be exploited for future herbicides.

For example, Arylex.eu, from Dow Agrosciences, received approval in the European Union and several other countries just a few years ago for its new herbicide, Arylex Active. Aside from being safe enough to pass the EU’s tough new regulations, this compound has been effective at controlling many resistant weeds. Even weeds that have developed resistance to other less specific synthetic auxin herbicides are being effectively managed with Arylex. This is thanks to its new site of action, which makes it more effective overall and gives farmers a new target in order to prevent weed resistance.

How farmers are fighting herbicide resistance (click here)

The families who grow the crops used to provide the world with food, fiber and fuel are on the front lines on the fight against herbicide resistant weeds. It is their obligation to develop the best weed management plan possible based on our current knowledge about weeds, resistance, and crop safety.

In order to prevent herbicide resistance from emerging, farmers know that they should rotate through multiple herbicides with distinct modes and sites of action. In some cases, these different products can be applied simultaneously in a complementary fashion. However, in other cases, applying two different herbicides at the same time can render them less effective. It’s up to crop growers to know the difference in order to kill weeds as effectively as possible. They must also be alert to the signs of weed resistance and know how to respond before the problem gets out of hand.

Although herbicides play an important role in any weed control strategy, even in organic farming, they should be combined with other best practices to be maximally effective. Certain techniques in crop rotation can be very effective at controlling weeds as compared to mono-cropping, for example.

We’re all in this together

Experts have estimated that we will need to increase our global food production by as much as 40% by the year 2050, and issues related to loss of arable land, climate change and, yes, weed resistance, are making this goal more daunting every day. Everyone involved in the agricultural industry needs to do their part to mitigate these risks to global food security. Fortunately, research scientists, farmers and consumers all have a common interest here: to provide the best, most abundant food possible and in the most sustainable way.