Embrapa's researcher warns about weed resistance in Brazil

The weed resistance is currently a biggest concern of the agricultural world. In Brazil, cases of resistance already occur in the South and begin to appear in the Midwest. According to the Embrapa’s researcher Fernando Adegas, you need to make the correct control to prevent this problem to reach Mato Grosso crops.

The alert is directed to technicians and producers who participate in the National Meeting of Harvest Technologies (Entec), in Lucas do Rio Verde. During the event, which took place May 21st-24th, Adegas did two lectures as part of the Continuous Training of Technicians who work in the productive chains of grains, fibers and systems integration, conducted by “Embrapa Agrossilvipastoril” in partnership with Aprosoja.

According to the researcher, the creation of weed resistance is occurring due to the successive use of the same herbicide, the glyphosate, in drying for direct planting and control of RR (Roundup resistant) genetically modified soy, corn and cotton crops. The population of resistant individuals increases, causing damage to crops.

"This is a major problem in the United States, Australia, Argentina and Southern Brazil. We show this scenario not to let this happen in the Cerrado. But the problem will probably happen. We want to reduce the intensity to see if farmers prepares better to have lower cost,"said Fernando Adegas.

According to the researcher, in Brazil there are five species resistant to glyphosate. One of them is ryegrass, most common in mild temperatures such as Rio Grande do Sul and Parana, and it should not get to MatoGrosso. But there are still a few species affecting the state.

Solutions
 
Adegas presented two measures that could be adopted to avoid weed resistance to herbicides in MatoGrosso crops: herbicides rotation and straw formation.

According to the researcher, there was a reduction in herbicides supply, but there were still options to be alternated with glyphosate.

"There still are alternatives, although they are very few. Just to get an idea, other countries had 30-40 products. But when glyphosate using started, it returned to 3-4 products used. We continue with other alternatives, but we are not using them. We need to re-use them. Even if it is in RR soybeans or corn,"he explained.

Adegas talked about the efficiency and practicality of glyphosate. However he alerted to a moderate use to prevent the loss of technology.

"Glyphosate is an exceptional product. Regarding herbicides, it can be said that it is the most complete one. It is relatively cheap and easy to use. It's so good that we should preserve it not to lose it," he warned.

Another alternative is straw formation. Weeds do not grow very well in covered soil, so the association of corn with Brachiaria, for example, it an important alternative to avoid the development of the most resistant plants.

"If you associate with a”brachiaria ruziziensis” or other Brachiaria you already avoid nearly 100% of resistant plants. The sequences in which you use the same herbicide and the little straw formation are easier to have more resistant plants,"he explained.

According to the researcher, the producers who make the correct weed management may avoid losses in the future.

"If you do this, some will be able to avoid, others will delay and others make it come with less intensity. One thing is certain: whoever has resistance in the property will spend more money,"said the researcher.