Integrated Weed Management

At the International Weed Science Congress in Prague, scientists from 57 countries came together to discuss the way forward in weed control and possible solutions against the global problem of weed resistance.

With the number of herbicide-resistant weeds growing dramatically worldwide, scientists at the Congress agreed that breakthrough innovations in weed research were urgently needed in order to address the severe agricultural problems of today and tomorrow. “It is high time that we speed up research in weed control,” said Hermann Stuebler, Head of Weed Control Research at Bayer, in the opening speech. “In order to prevent new resistances from spreading and preserve the efficacy of current weed control solutions, we need to provide farmers with new tools so that they can diversify their weed control strategies. For many farmers worldwide, new and resistancebreaking herbicides are a question of economic survival.”

In combating weed resistance, most manufacturers must emphasize on innovation, partnerships and dialogue. Main weed research activities should concentrate, on engagement in understanding resistance mechanisms, testing and developing new concepts and tools to manage resistant weeds, and communicating and sharing their knowledge and solutions.

Agrochemical companies should dialogue and showcase their activities which should be geared towards holistic approach to weed management and supports a strategy of developing integrated weed management (IWM) solutions for sustainable agriculture. IWM Program offers farmers customized solutions for weed control through cutting-edge seeds, crop protection products and a wide range of services such as diagnostic tools and prediction models – all backed up by the latest scientic insights. Bayer implements its IWM Program in local initiatives according to best weed management practices.

The battle for yield
Around 30,000 weed species worldwide are reducing the quality and volume of crop yields as they constantly compete with crops for nutrients, sunlight, space and water. What’s worse, the number of herbicide-resistant weeds is also growing fast: 252 of the 1,000 worst and most common weed species have developed resistance to 23 of the 26 known herbicide sites of action and to 161 herbicides in 91 crops and 67 countries (as of 19.12.16). Moreover, no new modes of action that could potentially control them are expected in the near future.

How weed resistance occurs
In every weed population there is a certain range of natural diversity in the genetic makeup of the plants. Naturally occurring mutations due to cosmic radiation or a plant’s internal DNA repair mechanisms, for example, contribute to this genetic diversity. Besides, several generations of a weed may well be exposed to several herbicide applications at different times during the cropping season. After application of a herbicide with a specific mode of action, there is always a chance that a few weed will survive and produce seeds or in the case of perennial species, rhizomes or other vegetative propagation structures. If the same herbicidal mode of action is applied again and again with no complementary non-chemical weed-control measures, the risk of resistance increases fast, and resistant weeds can soon take over an entire field.

How weed resistance develops – a theoretical example
Actual development depends on the particular weed and cropping system. How weeds are best managed Weed seeds return to the soil at the end of the season, only to emerge again and compete with crops. It is essential to implement management tactics to reduce the weed seedbank.

Some examples are detailed below:

• Implement a crop rotation that puts target weeds off balance.
• Implement soil management techniques that help to reduce the weed seedbank, e.g. stale seedbed, tillage or deep plowing.
• Apply weed seed control tactics at harvest time, e.g. mechanical and cultural practices that capture and destroy the weed seeds before they replenish the soil seedbank.

The Reality About Weeds
When you focus on what makes production agriculture tick, it comes down to just a few things. We love the land. We work every day to ensure a bright future for our families. And we want that bright future to be passed on to the next generation.

All of us worry about the Farm Bill, commodity prices and inputs, but when it gets down to the field level, weed management may just be one of the key issues of this decade. Can you imagine a drive across this country without seeing actively growing crops? If growers allow tough-to-control weeds to get the better of them, economies of scale have proven that weeds can overrun fields and decimate today’s and tomorrow’s profits.

The best way to preserve the effectiveness of weed control technologies is to ensure good control and eliminate weed seed production. It’s important to seize each and every opportunity to stop surviving weeds from producing seed. This will reduce the soil seed bank and selection pressure.

Game-changing solutions
We take weed management very seriously, using our extensive experience to work with you on innovative, integrated solutions for productive and sustainable farms. Crop Science is dedicated to bringing game-changing technologies to the local market to address the most important agronomic challenges farmers face. These solutions affect not only your profitability, but contribute to agriculture by providing healthier, more plentiful food for the world, one harvest at a time.

Our responsibility to provide effective weed management includes our Respect the Rotation initiative, which elevates the importance and grower adoption of herbicide diversity through the rotation of crops, traits and modes of action.

Crop Science also works with agronomists and university experts to continue to study the science of weed management. On our YouTube channel, you can see video clips of both growers and experts discussing this ever-changing issue and their belief in the power of good stewardship.

Tools to carry your farm into the future But it doesn’t stop there. Crop Science is a leading provider of herbicide-tolerant trait platforms and crop protection products to carry your farm into the future, ensuring that you have access to robust weed management programs.

Best Weed Management Practices
With no new modes of actions or technologies in sight, there is an urgent need to sustain the effectiveness of current products until new technologies can be developed and introduced. That’s why at Bayer we are encouraging farmers to help themselves by keeping herbicide technologies working well.

In practical terms, diversity means farmers need cross-crop rotation to vary their traits and crop protection products and practices, and combine them with non-chemical measures that reduce weed populations.

Tips for effective weed management
At Bayer we recommend that farmers follow these guidelines to enjoy the benefits of profitable and sustainable weed management:

Knowledge Exchange
Harry Strek in Frankfurt has a similar opinion: “We want to deliver consistent messaging based on sound scientific results. Farmers need to understand that herbicide resistant weeds are a problem that concerns every party involved in growing a crop but ultimately that the farmer alone has control over what goes on in his field.” Strek regularly visits farmers worldwide to share his experience face-to-face and gain valuable local insights. During these visits he and his team translate their research results into concrete and clear messages: “We want farmers to understand the importance of what they can do to make farming and controlling weeds a more sustainable practice. This includes following a good crop rotation and applying varying herbicides and supplementing this with non-chemical weed control measures. Because always using the same mode of action greatly increases the potential for developing new resistance,” Strek summarizes.

In most cases, his advice distils down to this: Using healthy crops to outcompete the weed, employing regular crop rotation and tillage and applying herbicides judiciously. “Diversity is the key and good agronomy is essential to sustaining the effectiveness of existing herbicides. The days of just being able to spray and forget are over. We need to be smarter about our use of precious chemical resources. It’s technology and brains combined,” says White.

Another Australian contributor to the international effort is Tim Scott. He manages a farm in Arthur River, in the southwest of Western Australia and also works as an agronomist at Agvivo, an agricultural consulting company. “We develop farm management plans together with the growers by taking the weed populations in their paddocks and their use of herbicides in the past into account,” explains Scott. “Based on this analysis, we help the farmers decide which herbicide to use in that particular year.”

The agronomist has done a lot of resistance testing with growers in the last couple of years and his work has been invaluable to get a better idea of what the local farmers are dealing with in terms of herbicide resistance. He even has a triumph to report: “Last year was regarded as a landmark year because the level of ryegrass resistance against one herbicidal compound decreased for the first time in five years. This is a trend that we must continue to support.”

The Australian success stories demonstrate that these and many other diverse efforts being led globally by researchers, inventors, farmers and agronomists are already contributing to a more sustainable control of weeds. “Nonetheless, resistance remains a big and growing problem around the world. It must be recognized as a major threat to the future of agriculture. To date, 246 different weed species have evolved resistance to common herbicides, diminishing yields by up to 70 percent. We don’t have the luxury of increasing the surface area we farm, so we must increase our farming efficiency. A major part of this is a better control of weeds and keeping resistance issues under control,” says Strek.

Courtesy: Bayer Cropscience Magazine