September 6, 2012

Volunteer Soybeans Potential Source of Rust Spores in Mato Grosso

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

While farmers in Mato Grosso are making final preparations for planting their 2012/13 soybean crop, they are also being reminded to redouble their efforts to eliminate any volunteer soybeans on their property or along the highways near their farms. Several weeks ago, technicians from the state department of agriculture visited the principal soybean production regions of the state and found a significant number of volunteer soybeans had not been eliminated and virtually all of the volunteer soybeans were infected with soybean rust.

The technicians returned from their survey with a grim assessment saying it is the worst they have seen since the 90-day soybean free period was put in place in the mid-2000s. The concern is that these volunteer soybeans will serve as a source of the disease once the 2012/13 soybean crop is plated in a few weeks. According to the Mato Grosso Institute of Agricultural Economics (Imea), soybean rust cost the farmers in the state R$ 364 million last growing season in lost production and increased chemical costs.

There are two main reasons why there are more volunteer soybeans in the state this year. The principal reason is because the rainy season did not end until late in June. This allowed soybeans that spilled out of trucks along the highways of the state to continue to germinate much later than normal. Since the margins of the highways are not mowed, all these volunteer soybeans continue to be exposed to soybean rust. The other contributing factor as to why there are more volunteer soybeans this year is because farmers plant Roundup Ready soybeans, which makes controlling the volunteer soybeans with herbicides much more difficult.

Eliminating these volunteer soybeans at this late date is going to be difficult because it is recommended that the plants be removed manually and then either buried, put in plastic bags, or burned. It might be possible to eliminate the soybeans manually around buildings and storage units, but it would be impossible to manually remove all the soybeans along the edges of fields or highways. It's just going to be something the farmers in the state will have to deal with this growing season.

Fines for not eliminating the volunteer soybeans can be R$ 50 per hectare, but at this point, officials are really not interested in collecting fines, but rather the elimination of the soybeans.