Weed management in coffee

Pre-emergent herbicide performs well in the management of resistant or difficult-to-control weeds in coffee crops, such as horseweed, bittergrass, brachiaria, crow's foot grass, viola string and milkweed.

Weeds directly interfere with coffee cultivation, competing for water, light, nutrients and space. This competition occurs during the establishment phase (molting), extending throughout the production cycle. Crops that cover the entire surface of the soil, such as soybeans and corn, for example, have a specific total period of interference, concentrating control on some stages of the crop. Coffee, as it is perennial and grown in larger spaces, requires weed control at various times of the year.

Weed control in coffee intensifies during warmer periods with greater precipitation, ideal conditions for the development of coffee and weeds. Some of the management methods used by coffee growers are chemically controlling weeds in the planting line (coffee skirt) and mechanical control between the rows. This method can continue until close to harvest, during which it is recommended to eliminate all weeds to facilitate this operation.

Glyphosate is one of the most used herbicides to control weeds in coffee. Among the characteristics of this herbicide are a broad spectrum of control, control of perennial plants, cost and selectivity by positioning (directed jet), in addition, it has no residual effect on the soil. One of the challenges in using this technology is the growing number of plants resistant to this solution.

The herbicide is not capable of causing resistance in plants, however it acts on selection pressure. Therefore, the repetitive use of the same technology provides the selection of biotypes, which present some degree of resistance. Plants such as horseweed (Conyza spp), bittergrass (Digitaria insularis) and crow's foot grass (Eleusine indica) are already resistant to glyphosate, making the management of these weeds difficult. It is known that an average of three to four post-emergence applications are carried out in the crop, thus favoring the selection pressure of resistant species and using a large number of machines for these operations, which causes an increase in cost. of production.

An alternative to the problem of resistance is the use of pre-emergent herbicides with different mechanisms of action, controlling these plants before emergence. Another related fact is that these herbicides have a residual effect, making it possible to reduce the number of entries into the area, thus reducing the cost of application. One of the challenges of using pre-emergent herbicides in coffee farming is understanding the dynamics in the environment. Unlike herbicides applied in powder form, soil factors such as pH, clay/sand content, organic matter and physical-chemical characteristics of the herbicide such as solubility, pka, half-life and koc directly influence the control effectiveness and selectivity of these technologies.

Falcon herbicide hits the market for pre-emergence weed control. The product has some characteristics such as selectivity for the crop, and can be applied in the initial stages up to coffee plantations in full production, having a broad spectrum of control, mainly for resistant or difficult-to-control plants such as horseweed, bittersweet, brachiaria, capim-pé-de-de- chicken, viola string, milkman, among others. One of the advantages of combining technologies is the synergistic effect of the formulated mixture, with the control of narrow leaves being amplified in the mixture, when compared to isolated active ingredients, and the excellent control on wide leaves.

To manage weeds in coffee, integrated control methods must be adopted. The herbicide glyphosate is a technology that can be used together with Falcon to control weeds before harvest. This way, the coffee grower can anticipate control and guarantee the residual effect of Falcon. Another position is the use of Falcon between the planting rows to control plants in pre-emergence, thus minimizing application costs or mechanical control between the rows.

In studies carried out, this herbicide was shown to be capable of transposing the corn straw layer (6t/ha), and can be applied directly on the straw, requiring 50mm of rain to transpose above 60% of the dose applied to the soil. , where the herbicide has its effect. Another study carried out was on litter (a layer that is above the ground and is made up of remains of leaves, twigs, fruits and other plant parts), where a very stable behavior was observed regarding the release of the product to the ground, in layers of 15t/ ha and 30t/ha. This is an excellent result when we evaluate other herbicides on the market.

With Falcon, it is necessary to evolve in understanding the dynamics of herbicides in the environment, dynamics in straw and living cover and work to make coffee growers aware of how the technology works and how they can use it. The Falcon brings benefits to the coffee grower in terms of gaining control, flexibility of use, management of resistant plants, among others, enabling an expansion of management tools.

 

Researchers from Renove Agropesquisa, Dr. Renan Fonseca Nascentes and Dr. Plinio “Saulo” Simões