**2. Pesticide use in Brazilian agriculture**

*Multifunctionality and Impacts of Organic and Conventional Agriculture*

examples of TSR mechanism, while reduced absorption, differential translocation, high metabolism, and glyphosate sequestration by the vacuoles are examples of NTSR mechanism [11]. Thus, it is necessary to know about the mechanisms of weed resistance to herbicides to perform good management practices for the prevention of the occurrence of new resistant biotypes in other areas and, mainly, for the determination of preventive management programs to the selection of resistant biotypes and also for the determination of the practices of weed control already selected [9]. The aim of the authors in this chapter was to present pesticide use and general

characteristics of glyphosate- and herbicide-resistant weeds in Brazil.

*Number of weed species with simple resistance to herbicides. Source: Heap [10].*

*Number of herbicide-resistant weed species per weed family. Source: Heap [10].*

**6**

**Figure 4.**

**Figure 3.**

The agricultural production in Brazil plays an important role in the Brazilian economy, thanks to which this country is one of the world's leading producers of agricultural commodities. To keep up with production, this sector uses intensively transgenic seeds and chemical inputs, such as fertilizers and pesticides—chemical or biological substances used to protect crops against the introduction and spread of pests such as insects, fungi, bacteria, viruses, mites, nematodes, and weeds [4, 12]. Regarding the function of pesticides, they all have the same common action, which is to block the vital metabolic processes of the organisms in which they are toxic.

Currently, the total amount of pesticide commercialized in Brazil is US\$10,522 billion per year, 14% less than 2014 (**Figure 5**), or 21% in a global market estimated to be worth US\$50 billion. In a country with a high pest index due to tropical climate, the farmers' challenge is to reduce pesticide application (which is nowadays the main pest management), as well as to reduce the cost of production and the associated risks to human health and natural resources.

Among the several alternatives for pest control in crops, the chemical method is still the most widely used, due to its practicality, efficiency, and speed. However, if pests are not controlled, they can drastically reduce the crop productivity. Among the pesticide classes, herbicides (selective and nonselective) used for weed control and also applied for crop desiccation represent 33% of consumption in the country, followed by insecticides (29%) and fungicides (28%) (**Figure 6**).

Due to the high total amount of pesticides used, some agricultural crops deserve attention, not because these products are intensively applied per unit of cultivated area but because these crops occupy large areas in Brazil. Half of the pesticides commercialized in the country are used in soybean crop, followed by the main crops such as sugarcane (12%), corn (11%), and cotton (9%) (**Figure 7**).

Pesticide use differs in the various regions of the country, where intensive and traditional agricultural (not use chemical product intensively) activities are mixed. Located in Midwest, the Mato Grosso state is the one that uses the most pesticides (24%) in the country, and the second is São Paulo state, located in Southeast

**Figure 5.** *Total commercialization of pesticides in Brazil from 2014 to 2018. Source: SINDIVEG [13].*

#### *Multifunctionality and Impacts of Organic and Conventional Agriculture*

(**Figure 8**). The consumption of pesticides in the Midwest increased in the 1970s and 1980s due to the occupation of the Cerrados and the cultivation of soybean, cotton, corn, and sugarcane continues to increase in this region. The South region represents 26% of pesticide consumption, while in the Northeast region, it is only 9%.

Empty pesticide packaging, unlike any plastic packaging, cannot be reused for domestic uses. This is because the products are aggressive, i.e., harmful to human and animal health, and can cause contamination if reused. And due to the toxicity of pesticides, their handling requires extreme care, attention, and personal protective equipment, and empty containers cannot be disposed in the dumping ground due to the aforementioned eminent risks. Therefore, all pesticides that are marketed in Brazil have empty packaging collected by the National Institute for Empty Packaging Processing (inpEV), which is responsible for the final destination of this material.

#### **Figure 7.**

*Commercialization of pesticides used by crops in Brazil. Non-food crops: reforestation, pasture, floriculture, and tobacco. Fruits: citrus, apple, grape, melon and watermelon, banana, and others. Vegetables: potatoes, tomatoes, onions, garlic, and others. Grains: wheat, oats, rye, barley, and peanuts. Others: stored grains and others. Source: SINDIVEG [13].*

**9**

**Figure 8.**

which exceeds one ton [17].

*Current Approaches to Pesticide Use and Glyphosate-Resistant Weeds in Brazilian Agriculture*

**3. Glyphosate: sales in Brazil and worldwide, origin and mode of action**

*Commercialization of pesticides for use in agriculture by Brazilian states. Source: SINDIVEG [13].*

Currently, the most efficient method used for weed control is the use of herbicides, mainly in large areas of cultivation, for which its rapid action added more viable costs. Among the herbicides used, glyphosate is the most marketed worldwide in more than 119 countries with about 150 trademarks for this product [14]. **Figure 9** presents the commercialized quantities of glyphosate and its channels in Brazil. According to the ABRASCO [16], 110 products with glyphosate alone have been sold in Brazil, in 29 different companies, and 173,150.75 tons sold in 2017, the amount being 3 times more than the second most commercialized herbicide, the 2,4-D. This considerable increase in sales was due to the production of corn and cotton after the development of transgenic soybeans, from 40,000 tons of products marketed to 300,000 per year in Brazil. In 2013, Asian countries, especially China and India, were the ones that consumed glyphosate-based products the most. At the same time, the United States accounted for more than 25% of all glyphosates marketed. The estimate is that in 2020, the demand for this herbicide is worldwide,

The discovery of glyphosate occurred in 1950, and this acid was an interesting complexion agent, a pH reducer, a detergent, and several other applications [18]. The glyphosate molecule was invented by the Cilag/Ciba industry in Switzerland, during the process of selection of chelating compounds for paints. In the mid-1960s, some scientists at Stauffer discovered other chelating properties of glyphosate. However, only in the early 1970s did Monsanto scientists discover the herbicide properties of glyphosate. Two decades after it began to be marketed, there were

*DOI: http://dx.doi.org/10.5772/intechopen.91872*

*Current Approaches to Pesticide Use and Glyphosate-Resistant Weeds in Brazilian Agriculture DOI: http://dx.doi.org/10.5772/intechopen.91872*

**Figure 8.** *Commercialization of pesticides for use in agriculture by Brazilian states. Source: SINDIVEG [13].*
