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June 1, 2012

Soy Producers in Brazil Prepare for 90-Day Soybean Free Period

Soybean producers in Brazil are preparing for the 90-day soybean free period mandated by most soybean producing states. In the majority of the states in Brazil, the soybean-free period begins on June 15th and continues through September 15th. In eastern areas where soybeans are planted later such as Tocantins, the soybean-free period begins on July 1st and continues through September 30th.

These soybean-free periods were implemented as a way to help control the spread of soybean rust. The disease was first discovered in Brazil in 2000 and it has now become a chronic problem throughout the country. The rust spores can remain viable without a host plant for about 60 days, so the idea behind this soybean-free period was to eliminate as many of the host plants as possible in the hope that most of the spores will die during that period. The spores can still survive on native plants, but the elimination of soybeans can help delay the spread of the disease once a new crop of soybeans are planted.

During this soybean-free period, producers must eliminate any volunteer soybeans that may have germinated in their recently harvested soybean fields, or along the sides of the fields, along roadways, and around storage units. Grain elevators and transportation companies must also eliminate volunteer soybeans that may have spilled during the handling of the grain. Most states send out technicians during this period to inspect fields and roadways in search of any volunteer soybeans. If live soybean plants are found during this period, the land owner is notified and given 10 days to destroy the plants. If the plants are not destroyed within ten days, the fines can be extremely high.

There may be more volunteer soybeans than normal this year in Brazil because of the extended rainy season. The dry season in central Brazil usually begins by early May and the hot and dry conditions can impede the germination of any spilled soybeans. This year though, the rains continue to fall and there is ample soil moisture for wayward soybeans to germinate.

The only exception to this prohibition is for scientific research and seed increases. All of the soybeans planted for research or seed increase must be registered and approved in advance by the state Minister of Agriculture and they are closely monitored for the presence of the disease. Leaf samples are collected on a regular basis to detect the presence of the disease and these fields must be sprayed at least once with an approved fungicide.

The rust spores are very light and the wind can spread the foliar disease easily from field to field. Soybean rust can devastate a soybean field and controlling the disease has costs Brazilian farmers billions of dollars in lost production and chemicals costs, so it is in their best interest to control the disease as best as possible.

When the prohibition was first implemented in Mato Grosso, the state required that each center pivot irrigation system in the state be registered with the state and outfitted with a GPS transmitter to monitor its movements during the dry season. If movement was detected, technicians would travel to the site and verify that it was not a field of clandestine soybeans. Initially, a few farmers tried to avoid the prohibition, but that is no longer the case because farmers realize its importance in controlling the disease.

Scientists and farmers feel the soybean-free period has been critical in the success of controlling the disease. Researchers have developed soybean varieties that are more tolerant to the disease, but completely resistant soybean varieties have not yet been developed.