Effective measures are essential to prevent the spread of invasive plants in Brazil

Used, imported harvesters are the main means of dispersing palmeri pigweed

12.09.2023 | 14:02 (UTC -3)
Christina Tordin
Plants that were destroyed in MT; image: disclosure
Plants that were destroyed in MT; image: disclosure

Researchers from Embrapa, together with the Ministry of Agriculture and Livestock of Brazil (Mapa) and the USA warn that used cotton harvesters imported from the USA are the main routes of seed dispersal of the palmeri pigweed (Amaranthus palmeri) in Brazil. It is a plant capable of causing major productivity losses in annual crops. It was initially detected in the state of Mato Grosso in 2015 and later found in Mato Grosso do Sul, in 2022.

According to Dionísio Gazziero, a researcher at Embrapa Soja, pigweed is a plant that is difficult to control, has aggressive growth, is highly prolific and is resistant to herbicides. “Therefore, it is important that harvesters are very well cleaned and decontaminated. These measures reduce the risk of a seed going unnoticed. Cleaning prevents introduction into new areas and must be carried out before the equipment moves to another property, since the seeds are very small and difficult to see, especially when mixed with harvester waste”, he explains.

The palmeri caruru is characterized by its rapid growth. Under ideal conditions these plants can grow 2 to 4 cm per day. This fact can harm the effectiveness of post-emergent herbicides, as delay in application can reduce their effectiveness. For this reason, in areas that have problems with palmeri pigweed, it is very important to use pre-emergent herbicides to help control them. Inadequate control can make harvesting unfeasible, increase the need for the use of herbicides, increase production costs and cause enormous losses for Brazilian agriculture.

State research and agricultural defense bodies and Mapa are working to put together strategies to prevent it from spreading. Agile government decision-making and monitoring compliance with established phytosanitary measures, combined with the commitment of producers, public and private institutions, have contributed to the containment of this plant in infested areas. "However, it is necessary to establish a federal Normative Instruction establishing basic guidelines to be followed in the case of detection of the pest. This Instruction would help speed up the process of pest containment measures, highlights researcher Alexandre da Silva, from Embrapa Milho and Sorghum.

The presence of this new species of pigweed, which until then had not been registered in our country, creates serious problems for soybean producers. "The information on how this plant managed to enter Brazil serves as a warning to all farmers who import used machinery and to plant surveillance bodies and those using third-party machinery, who move with them from one area or state to another ”, he emphasizes.

Researcher Antonio Cerdeira, from Embrapa Meio Ambiente, explains that the plant is easily confused with other species of pigweed, common in Brazil. If its presence is suspected, it is necessary to notify the local agricultural defense agency to identify and confirm the suspicion. When in doubt, the producer must choose to eliminate the plant in his area to prevent its proliferation.

The alert carried out by Mapa to state agricultural defense bodies and the monitoring of crops carried out by these institutions have allowed the early identification of some infested areas and contributed to reducing the speed of spread of this species, avoiding or delaying a new problem for agriculture. Brazilian.

Containment strategies

After being classified as a quarantine weed, the palmeri caruru is now included in the federal government's Official Pest Control Program.

In the State of Mato Grosso, the Carurupalmeri Containment Committee was established with the aim of supporting agricultural defense bodies (Indea-MT) in actions to combat this weed plant. State agricultural inspectors were trained to identify species and carry out surveys in the States. Subsequently, agricultural defense agents from other States were trained and have included observation of the occurrence of this weed in inspected crops in their routine. Actions aimed at farmers were carried out, highlighting the importance of raising awareness in the sector about the problem as well as identification and control. The engagement of the agricultural community is essential to contain the pest.

“It is important to reinforce and review the inspection policy on the import of used machinery, as well as on the transit of machinery, especially between States after it was detected in Brazil”, highlights Gazziero.

Mosaic Biosciences March 2024