December 4, 2015

Wetness and Soybean Rust Worries Farmers in Rio Grande do Sul

Author: Michael Cordonnier/Soybean & Corn Advisor, Inc.

Farmers in the state of Rio Grande do Sul in southern Brazil have been struggling with excessive rainfall over the last several months resulting from the strong El Nino. The first crop impacted by the wet weather has been the winter wheat crop which ended up being extremely disappointing. Excessive wetness persisted during the entire time when the wheat was maturing and being harvested and as a result, wheat yields ended up being half of what was expected and the quality of the grain was very poor.

The difficulty with the wheat harvest has also impacted the soybean planting in the state. A significant portion of the soybeans in the state are double cropped after wheat and since the wheat harvest was delayed, the soybean planting was delayed as well. In the municipality of Ijui, which is located in the northern part of the state, the soybean crop is now 90% planted, but it is estimated that ten thousand hectares of soybeans in the municipality will need to be replanted due to excessive wetness. The situation is similar all across the northern part of the state. Any replanted soybeans will be planted after the ideal planting window has passed and are expected to have a lower yield potential.

The soybean yields in the region were expected to be in the range of 55 sacks per hectare (3,300 kg/ha or 47.8 bu/ac), but that is no longer expected for the later planted soybeans.

Additionally, the wet weather has raised the possibility of a high level of infestation of soybean rust in this year's soybean crop. The state has registered 31 of the 88 confirmed cases of soybean rust in Brazil thus far and there is a concern that rust could be a significant problem this growing season. Continued wetness could make it more difficult for farmers to make the timely fungicide applications that are necessary to keep the disease under control.

Controlling soybean rust was the main topic of discussion at a meeting held earlier this week by the State Committee for Soybean Rust. The meeting was organized by the State Secretary of Agriculture and it brought together technical experts to discuss the best practices available for controlling soybean rust. After the meeting, the Secretary of Agriculture released of list of best practices including:

  • Planting early maturing soybeans in order to shorten the time that the crop is exposed to the disease.
  • Elimination of all volunteer soybeans between growing seasons in order to reduce the possibility of the disease being carried over from one growing season to the next.
  • Harvesting soybeans as quick as possible once the crop is mature.
  • Monitoring the soybean crop as soon as it is planted for the presence of the disease.
  • Only using fungicides registered by the Minister of Agriculture for the control of rust.
  • Rotating the fungicides used to control the diseases and to not over use the fungicides.
  • Plant soybean varieties more resistant to the disease.