Práticas de manejo associadas a resistência de plantas daninhas a herbicidas em propriedades nos municípios do Rio Grande do Norte

Abstract

Even though weed infestation has positive aspects, it has already been proven to have a negative impact on a crop. The damage caused by plants, then, weeds, can be direct or indirect. The identification of weeds is the first step towards the development of a management program. Currently, weed resistance is among the biggest agricultural problems in the world and each year, new cases of resistance are identified in Brazil and in the world. There are 514 unique cases of resistance worldwide, both single and multiple. Biotypes of weeds resistant to herbicides exist because the natural genetic diversity that exists in weed populations is responsible for the appearance of resistance, and the herbicide is not the agent of creation of resistance, but only of selection. Some practices can be implemented to minimize the risk of emergence of resistant plants such as: preventive, cultural, mechanical, manual, biological, direct planting system, chemical and even biotechnological. With that in mind, a rotation must be inserted in the system: “the rotation of mechanisms of action of agrochemicals”. Although this biotechnology innovation is not used directly on weeds, its application on agricultural crops completely changes the way they are managed in a field, including herbicide rotation, avoiding weed resistance. Genetically modified plants are tolerant to broad-spectrum herbicides, allowing more efficient control, at a lower cost and with a reduced number of herbicide applications, generating greater productivity and less environmental impact. The objective of this work is to analyze the changes in weed management resulting from the application of herbicides generating plants resistant to this management. To do so, it will be discussed how the identification of weeds is done to define the management to be adopted and, in this way, be able to minimize problems, including resistance. In a large-scale agriculture, production without the use of chemical control would hardly be possible, and in view of this, the integrated management of weeds is undoubtedly the best way to avoid interference and competition between weeds and cultivated plants, even genetically modified ones and thus ensure greater profitability for the producer, avoiding weed resistance to herbicides.