Five answers to Syngenta's new broadleaf herbicide: FLEXSTAR™ GT

With each harvest, the challenges in the field seem to increase, don't they? However, one challenge in particular has forced the search for new strategies and tools and caused many headaches for producers: weeds.

We are not talking about a small and isolated problem. Weeds are present in practically all producing areas in Brazil, with the potential to reduce up to 90% of soybean yield if control is not carried out. They register average losses of 13 to 15% in grain production, which can worsen in a scenario of inefficient control. 

In the case of soybeans, the complexity goes even further: the presence and pressure of broadleaf weeds have increased significantly in recent harvests. Considering that soybeans are also broadleaf plants, finding selective options that control weeds without affecting soybeans is essential.

Caruru, trapoeraba, leiteiro, picão-preto, poaia-branca, and corda-de-viola, among others, are some of the main species that have spread through Brazilian crops. From the north to the south of the country, these weeds have been causing headaches for producers, who are forced to seek increasingly complex solutions for managing the different invasive species.

And the problem doesn't stop there. With the evolution of resistance to glyphosate, these weeds not only increase more quickly, but they also become more difficult to control. This has led producers to resort to product mixtures, seeking alternatives to maintain the productivity of their crops protected from weed competition.

It was precisely with this complex and challenging scenario in mind that Syngenta developed a solution that responds to these main problems: FLEXSTAR™ GT

Continue reading to find out how Syngenta’s new broadleaf herbicide responds to the main current demands in managing these threats.

1. To manage long-term weed resistance: a potent combination of actives

Problem: 

Currently, around 97% of soybeans grown in Brazil are genetically modified, with Roundup Ready (RR) technology being the most widely used. RR soybeans are genetically modified to be resistant to glyphosate, a broad-spectrum herbicide that acts systemically, controlling a wide range of weeds.

Since its introduction in Brazil, RR soybean has facilitated crop management, making weed control more efficient and less costly. However, the extensive and repetitive use of this herbicide has resulted in selection pressure for the most resistant species. 

Species such as the caruru (Amaranthus spp.) and the beggartick (Bidens pilosa) are classic examples of plants that, over time, have had species with glyphosate resistance selected and disseminated. This phenomenon has made chemical control of these species much more complicated and less efficient, directly threatening crop productivity.

Need: 

Growers now need a solution that not only controls resistant weeds but also helps slow or prevent the selection of new resistance. This requires combining different modes of action to target invasive plants in other ways, reducing the chances of adaptation and resistance to treatment.

FLEXSTAR™ GT Response: 

FLEXSTAR™ GT addresses this challenge by combining two powerful active ingredients: glyphosate and fomesafem. Glyphosate remains effective on many weeds, while fomesafem, a PROTOX enzyme inhibitor, works differently, targeting broadleaf weeds in a way that glyphosate alone cannot. 

This dual action is crucial to breaking resistance and promoting effective control, even in weed populations that have already shown resistance to glyphosate.

2. For increasing broadleaf weed pressure in soybeans: superior control with selectivity

Problem: 

As mentioned, in recent years, there has been a significant increase in the incidence of broadleaf weeds in soybean crops. In addition to spreading rapidly, these plants produce a high volume of seeds, which favors reinfestations throughout the harvest.

Because they are highly competitive, stealing nutrients, water, and light from the soybean crop, the presence of these weeds, together with the soybean, directly impacts the crop's yield, often requiring intervention and applying them to the already emerged soybean.

In this scenario, using broadleaf herbicides that are not selective for soybeans can cause severe problems in the crops. These herbicides, while effective in controlling weeds, do not distinguish between the weeds and the main crop. This means that when applying them, there is a significant risk that the herbicide will damage the soybeans, compromising their growth and development.

When soybeans are exposed to non-selective herbicides, they can suffer from mild phytotoxicity, which slows their growth, to more severe damage, such as leaf burn and death of entire plants. This damage can result in a significant reduction in crop density, affecting overall crop productivity. In addition, damaged soybean plants tend to be more susceptible to pests and diseases, which can lead to additional losses.

Need: 

Controlling these weeds requires a herbicide that is highly effective against broadleaf species but is also selective, i.e., one that combats the weeds without harming the soybeans. This selectivity is crucial to protecting the main crop while eliminating competition from the weeds.

FLEXSTAR™ GT Response: 

FLEXSTAR™ GT responds to this challenge thanks to its formulation and application flexibility in post-emergence. It promotes superior control of the main broadleaf weed species, with specific conditional selectivity for RR soybean due to its glyphosate component. 

Because they are genetically modified to resist glyphosate, RR (Roundup Ready) soybeans allow FLEXSTAR™ GT to act after the crop emerges, controlling weeds sensitive to this molecule without damaging the soybeans. 

The combination with fomesafem further reinforces selectivity, providing effective control of glyphosate-resistant broadleaf weeds without causing phytotoxicity to soybeans.

3. For tank mixes needed for resistant weeds: a ready-mix herbicide

Problem: 

With increasing weed resistance, many growers are forced to make tank mixes, combining different herbicides to try to achieve effective control. 

However, preparing these mixtures is a complex task that requires precision and technical knowledge. Any dosage error or inadequate combination can lead to ineffective results, damage the crop, or, even worse, increase weed resistance.

Need: 

To simplify management and ensure effective weed control, growers need a solution that eliminates the need for complicated tank mixes but still provides the efficacy required to deal with plants resistant to a given herbicide molecule.

FLEXSTAR™ GT Response: 

FLEXSTAR™ GT is a ready-mix herbicide that combines two molecules and two distinct modes of action in a unique, balanced formula. 

This means growers no longer need to worry about preparing complex tank mixes – everything is already ready and in the correct proportions. This convenience not only saves time but also reduces the risk of human error, promoting more effective and consistent control of resistant weeds.

4. For post-emergence control: a systemic and effective solution

Problem: 

One of the biggest challenges in weed control is a post-emergence application when plants are already established and may be more resistant to herbicide treatments. In a scenario where soybeans are already growing, weeds competing directly for vital resources make control even more urgent.

Furthermore, with soybeans in the field, the application of the herbicide can become more complex since the commercial crop can overwhelm the invasive plants and make it difficult for the product to reach the right target.

Need: 

Growers need a herbicide that is effective even when weeds are already in advanced growth. In addition, this product must have a systemic action to ensure that the herbicide reaches the entire plant even when faced with obstacles during application, eliminating weeds and maintaining operational efficiency. 

FLEXSTAR™ GT Response: 

FLEXSTAR™ GT is highly effective in post-emergence applications thanks to its systemic action. This means that the herbicide is absorbed by the leaves of the weeds and transported throughout the plant, providing complete elimination. This feature is handy in the later stages of weed growth, when other herbicides may fail to deliver complete control.

5. For the various species of broadleaf weeds present in soybeans: a solution with a broad spectrum of control

Problem: 

The occurrence of broadleaf weeds in soybean crops has increased significantly, with species such as pigweed (Amaranthus spp.), trapoeraba (Commelina benghalensis), and beggarticks (Bidens pilosa) gaining prominence. 

The presence of several species with different patterns of resistance and tolerance to herbicides requires greater care in the identification and selection of solutions so that the product used is genuinely effective against each specific target. This approach can result in greater operational complexity, increased costs, and increased risk of application errors.

Need: 

Species variety, resistance, and increasing tolerance require solutions that can address multiple threats simultaneously.

To address this diversity of weeds, a herbicide with a broad spectrum of control is needed that can effectively treat several broadleaf species without affecting soybeans. 

FLEXSTAR™ GT Response: 

FLEXSTAR™ GT responds to this challenge by offering broad-spectrum control with its combination of active ingredients. This compelling blend enables control of a wide range of broadleaf weeds, including those with varying levels of resistance and tolerance. 

Glyphosate and fomesafen attack weeds differently, enabling superior and comprehensive control and promoting clean and productive crops even in challenging conditions.

Positioning of FLEXSTAR™ GT: when to apply?

FLEXSTAR™ GT offers flexibility and effectiveness with its specific application guidelines:

• Single application: recommended when soybeans are at the V2-V3 stage and weeds are at the 2-3 leaf stage. This timing ensures that the herbicide acts efficiently on young weeds, with soybeans developing at an early stage, reducing the risk of damage to the commercial crop.

  
  

• Sequential application: For more comprehensive coverage, the first application should be made when soybeans are at V2-V3 and weeds are at the 2- to 3-leaf stage. The second application, made 14 days after the first, helps ensure complete control by controlling any weeds that may have germinated or grown after the first application.

This strategic approach allows FLEXSTAR™ GT to maximize weed control and minimize interference with soybeans, promoting efficient and productive management.

More about FLEXSTAR ™ GT: Post-Emergence Weed Control in Soybeans

The increasing diversity of broadleaf species, many of which are resistant to traditional herbicides, has made controlling these weeds a complex and strategic task. This context requires careful planning and the use of innovative solutions that can address the resistance and rapid spread of weeds.

In this sense, integrated weed management (IWM) becomes indispensable. This approach combines different control strategies – chemical, cultural, and mechanical – to minimize the impact of weeds in a sustainable way. 

Crop rotation, use of plant cover, careful application of herbicides, and constant monitoring of crops are some of the fundamental practices for keeping weeds under control and avoiding the selection of resistant biotypes.

Advances in technology and the development of new formulations have proven to be essential. The integration of practical techniques and the use of products that offer both selectivity and broad-spectrum control, such as FLEXSTAR™ GT, are pillars for protecting soybeans and maximizing yield.