How to control sourgrass? Find out now!

“The farmer who does not control the weeds today will not harvest tomorrow.” – Popular saying

THE bitter grass (Digitaria insularis) is one of the most aggressive weeds in competition with soybeans, causing great losses.

According to data from Embrapa, the presence of this grass can reduce crop productivity by up to 44% if not properly controlled.

In more advanced situations, this reduction can reach 70%, depending on the level of infestation.

To avoid these losses, it is essential to adopt effective strategies bittergrass management. Controlling this weed requires careful planning, combining different methods, such as the use of herbicides for sourgrass, crop rotation and preventive measures.

Throughout this article, you will learn about the characteristics of this grass, the challenges imposed by its glyphosate resistance and best practices sourgrass control in soybean and corn crops.

So, pay attention to the tips and information to ensure the productivity and profitability of your harvest.

Understanding sourgrass and its damage to crops

THE bitter grass is a weed that is very harmful to crops in Brazil. It is a big problem for soy and corn.

In fact, it can reduce soybean productivity by up to 44%, according to Embrapa.

This plant has many seeds, about 100,000 per plant. This helps it spread over many areas. The seeds can germinate all year round, making it difficult to control.

It is more common in the Central-West, Southeast and South of Brazil. There, the losses are greater.

THE bitter grass competes for water, light and nutrients, so this affects crop growth and productivity. According to the Terra Magna, infests almost all of Brazil and many grain crops.

To minimize losses, it is important to use efficient management strategies. A combination of chemical and cultural methods is crucial. It is important to act preventively, avoiding the growth of weeds.

Using specific herbicides, removing weeds, covering the soil and controlling biologically are good practices. In addition, fertilizing well helps to strengthen crops and reduce damage.

Monitoring crops and controlling weeds is essential. This helps to minimize damage caused by bitter grass and maintain productivity.

Sourgrass resistance to glyphosate

THE bitter grass is becoming a major challenge for Brazilian farmers. This is because it is becoming increasingly resistant to glyphosate.

The first signs of resistance appeared in 2008, in Paraná. Since then, the plant has spread throughout the country.

A 2016 study showed that 87% of sourgrass plants near highways in several states were resistant to glyphosate.

This has caused concern among growers. Glyphosate is widely used to control weeds.

THE glyphosate resistance It arose because herbicide was used a lot. Direct planting, which began in the 1990s, made bittergrass more important.

Repeated applications of glyphosate selected for resistant plants.

In 2016, sourgrass also showed resistance to other herbicides, such as fenoxaprop and haloxyfop-p-methyl. This makes control even more difficult because it limits herbicide options.

To have hardy bittergrass in crops can greatly increase costs. In areas with resistant soybeans and buva, costs can rise up to 222%.

Without a doubt, this data shows the importance of finding ways to control bittergrass and avoid further resistance.

Management strategies for sourgrass in the off-season

The off-season is ideal for controlling sourgrass. During this time, there are more management options.

It is important to apply herbicides when the plants have up to 2 tillers. This increases the chances of success.

Sourgrass has reserves that herbicides do not affect. Therefore, late control may require repeated applications. This leaves the reserves without the strength to regrow.

The herbicides used initially are systemic, such as glyphosate and graminicide. Then comes the use of contact herbicides, such as glufosinate ammonium and paraquat.

The interval between applications varies from 10 to 20 cm, depending on regrowth. By following these strategies, it is possible to reduce the infestation of sourgrass. This helps to avoid losses in the productivity of future crops.

It is also important to adopt preventive practices. Avoiding fallow areas and using straw from previous crops are essential.

Combining these practices with the use of selective herbicides creates an effective plan against hardy bittergrass.

Proper management during the off-season is crucial to prevent the spread of bittergrass. This ensures crop success and producer profitability.

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Use of post-emergent herbicides to control sourgrass

You post-emergent herbicides are essential for controlling sourgrass. The selective graminicides, such as clethodim and haloxyfop, are very effective.

They control small plants well and are great for first use in sequential management.

THE glufosinate ammonium, known as Finale, is another great herbicide. It kills small plants and is good for sequential management. The ideal dose is 1.5 to 2.0 L/ha, and the effects are seen within 5 days.

Having only six sourgrass plants per m² can reduce soybean productivity by 44%. Therefore, using post-emergent herbicides is crucial to the success of the crop.

Sourgrass plants are most susceptible to herbicides when they are still young. This shows the importance of controlling them early to avoid losses.

Application of pre-emergent herbicides to control this grass

To use pre-emergent herbicides is essential for dealing with sourgrass, especially in heavily affected areas.

Only 14% to 18% of soybean farmers use these products, but their use is growing. This is because many weeds are becoming resistant to herbicides.

You pre-emergent herbicides help to seed bank control of the soil. They reduce the chance of sourgrass growing.

Products such as Diclosulam, Flumioxazin, S-metalachlor and Trifluralin are used for this.

These products can be applied in autumn management or in the apply and plant system. It is important to consider factors such as selectivity, persistence in the soil and humidity. This helps to ensure the best result, as explained in the blog Aggravation.

Studies show that pre-emergent herbicides are very effective against sourgrass. In a study at the Federal Institute of Goiás, the products Imazetapir+Flumioxazine and Sulfentrazone controlled more than 90% of sourgrass.

They are also a good option financially, as they reduce the need to apply post-emergence herbicides.

Therefore, use pre-emergent herbicides is a good strategy for controlling sourgrass. This helps reduce the seed bank and increases crop productivity.

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Management of sourgrass in soybean and corn crops

To control sourgrass in soybeans, use selective herbicides is a good strategy. This is effective when the plants are young or re-sprouting.

The graminicides clethodim and haloxyfop, together with glyphosate in RR soybeans, are efficient options.

In areas with a lot of grass, using pre-emergent herbicides is a good idea. This helps to reduce the number of seeds in the soil. Products like diclosulam, flumioxazin, and s-metolachlor are good for this.

In corn, controlling sourgrass is more difficult. This is because both are grasses. To control it, using pre-emergent herbicides such as trifluralin, s-metolachlor and isoxaflutole is a good option.

In post-emergence, nicosulfuron, tembotrione and mesotrione are good.

It is important to remember that there are no selective herbicides for sourgrass in advanced or perennial stages in corn..

In these cases, using integrated practices such as crop rotation and monitoring the areas is essential. This helps prevent the problem from spreading.

Conclusion

Integrated management is essential to deal with sourgrass. This weed has many seeds and is resistant to glyphosate. Therefore, it requires a strategic plan to be controlled.

To create a good plan, it is important to analyze the crop situation. This includes the level of infestation and the particularities of the crop. An agricultural engineer can help you choose the best strategy.

New technologies can also help control sourgrass. For example, cultivars resistant to herbicides and graminicides such as haloxyfop are good options.

Good fertilization, with nutrients such as potassium and phosphorus, can also help.

To overcome bitter grass, it is important to use a integrated management. Stay tuned for new technologies and seek help from professionals.

This way, you can protect your crops and increase productivity.