Ronald Leichtle

Fighting the Growing Resistance of Weeds

Imagine if the cost of agricultural production tripled because of resistant weeds. Studies conducted by Embrapa - the Brazilian Agricultural Research Corporation - estimate that soybean crop production costs will increase from 42% to 222% per hectare due to weed resistance in Brazil. Or consider, the damage the presence of horseweed (Conyza bonariensis) can cause per square meter, according to the Institute of Agrarian Research - INTA - it can go up to 53 kg of loss per hectare in soybean cultivation. Weed resistance is a great concern, and that is why it is imperative to develop methods to solve this situation.

The fact that weeds harm crop yield around the world is nothing new. In the United States, the first cases of resistance occurred in the 1960s, while in Latin America the incidence intensified in the 1980s. The International Survey of Herbicide-Resistant Weeds has already registered 480 cases, covering 92 crops spread in 69 countries. To minimize the effects of this worrying scenario, and to contain the spread of herbicide-resistant weeds, Bayer and LB-Track are working together to develop an innovative method for their quick detection in Latin American crops.

But what are weeds? These are plants that appear spontaneously “out of place” in fields and generally affect plant growth and crop area aesthetics. In general, they appear due to the continuous and long-term use of herbicides of a same chemical group, with the same active principle, which favors the natural selection of species that develop tolerance to the applications of these agrochemicals through each cycle. The presence of weeds influences agricultural production, since they are in direct competition with crops for nutrients, moisture, light, and space.

Ronald Leichtle, Director of LB-Track
Ronald Leichtle, Director of LB-Track
Ronald Leichtle,
Director of LB-Track

Weeds affect many types of crops around the world, especially wheat, soybean, corn, and rice plantations, which are abundant in Latin American fields. That is why many countries in the region, including Brazil, Argentina, Chile, and Colombia, are looking at ways of tackling the issue. These invasive plants also affect fruit and vegetable cultivation, posing a major threat to agricultural production as a whole. It is important to note that, internationally, almost all herbicides have presented resistant weed problems in one or more production systems.

Creating mechanisms to combat this threat involves incorporating integrated weed management, which increases the variety of tools available to control the weed populations over time. Basically, this means using techniques such as crop rotation, good agronomic practices in crops to ensure rapid coverage, and avoiding seed rain, among other crop and mechanical measures. In the case of the chemical tool, it is necessary to alternate the modes of action of the herbicides used in a given area.

Because it is a common and frequent problem, consultants and farmers usually hire laboratories in which seeds are tested to see how they might be affected with the use of herbicides at different doses and combinations. It is also possible to carry out genetic tests to detect mutations in plants that have developed resistance to some herbicides. Both methodologies are fairly accurate in detecting weeds but, unfortunately, they take time and are expensive.

Therefore, to speed the process up, Bayer and LB-Track signed a collaboration in late 2017 to find a solution to detect the presence of resistant weeds in a timely and cost-effective manner, so that the producer and field advisor can develop timely strategies to control or contain them. The methodology under development incorporates advanced spectrograph and analytic tools. So far, the results have shown they are very promising for application in the field. With these tools, it will be possible to reduce the uncertainty about the presence of resistant weeds, to apply better control strategies, decrease costs, and reduce production losses due to the presence of weeds.

It is essential to combat weed resistance in order to achieve the levels of agricultural production needed to meet the global demand for food, and the sustainability of agribusiness which may be jeopardized by these plants. We are confident that over the three years of the collaboration agreement we will be able to identify a viable solution to solve this important threat to the sector. We are taking the challenge to fight weeds head on.

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Joelma Amaral
July 10, 2018 - 06:15 PM

Congrats for the activities in the field

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