Impacts of goosegrass on soybean crops and the importance of integrated management

Eleusine indica is a highly resistant and prevalent weed in soybean crops. This plant’s resistance to herbicides such as ACCase inhibitors and glyphosate poses significant challenges, making control difficult and reducing productivity. In Brazil, resistance to glyphosate, clethodim and haloxyfop increased by 52%, 21% and 42%, respectively, over the last six harvests. This year, resistant biotypes total 79% for glyphosate, 68% for haloxyfop and 41% for clethodim.

Inadequate management practices, such as the repetitive use of similar-acting herbicides and lack of crop rotation, intensify the spread of Eleusine indica.

Weed competition from goosefoot grass

The presence of Eleusine indica in soybean crops generates competition for water, light and nutrients, severely impacting productivity.

Studies indicate that high infestations can reduce grain production by up to 80%, depending on the time of year and the density of the infestation. Data from Fundação MT, Embrapa and Syngenta indicate that significant losses occur after 14 days of coexistence between soybeans and grass, reaching 10 bags/ha in 21 days.

Clean management in the agroecosystem

Integrated Weed Management (IWM) is a strategy that combines cultural, mechanical, biological, and chemical practices to control goosegrass and reduce herbicide use. Crop rotation, for example, interrupts the weed's life cycle, while the use of fertilizer and mulch discourages seedling emergence. Fast-establishing soybean cultivars increase crop competitiveness.

Use of pre-emergents

Pre-emergent herbicides are essential for controlling Eleusine indica, as they inhibit weed germination in the soybean, favoring its initial development. They facilitate the action of post-emergent herbicides by reducing the selection pressure for resistant plants. If weed control occurs after 14 days, selective soybean herbicides will no longer be effective in controlling resistant biotypes. Therefore, the integrated use of methods, including pre-emergent methods, is crucial to prevent the multiplication of resistant plants and increase the number of viable seeds in the field.

Syngenta has in its robust portfolio the most complete pre-emergent herbicide on the market.

EDDUS Herbicide

EDDUS® represents an innovation in pre-emergent selective weed management in soybean crops, the result of years of research and development conducted by Syngenta experts.

While many herbicides use only one mechanism of action against weeds, EDDUS® combines two modes of action, offering more comprehensive control.

Its formulation includes two complementary active ingredients: fomesafem and s-metolachlor. Fomesafem inhibits weed photosynthesis, while s-metolachlor interferes with the cell division process. This combination ensures effective and long-lasting control.

EDDUS® is a selective herbicide for soybeans, which allows it to act exclusively on weeds, without causing phytotoxicity to soybeans, ensuring effective treatment without compromising the crop.

With a broad spectrum of action, EDDUS® is effective against several species of weeds, including grasses and broadleaves, such as pigweed, sourgrass and goosegrass, which often represent the biggest problems for soybean crops.

Soybean farmers who choose EDDUS® can count on the following benefits:

• broad spectrum, fighting both grasses and broadleaves;

• high selectivity, avoiding phytotoxicity to the soybean crop;

• high performance, controlling glyphosate-resistant weeds, such as sourgrass, goosegrass and pigweed;

• accelerated desiccation, with initial post-emergence action on weeds;

• high-tech formulation ensuring stability in adverse conditions;

• anti-resistance management: two active ingredients with different and complementary mechanisms of action.

* By Nubia Maria Correia (Embrapa Cerrados) and Lucas Heringer Barcellos Júnior (MT Foundation)