March 25, 2011

New Soybean Anomaly Appears in Brazilian Soybean Fields

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

Soybean researchers in Brazil are investigating a new soybean anomaly that has recently appeared in Brazilian soybean fields. So far it has only been reported on soybeans grown at higher elevations of central Brazil and at this point, the cause of the anomaly or the extent of the problem is unknown.

The anomaly causes the plant to dry down and die from the top down, which is contrary to most diseases that usually start at the base of the plant and work their way up. The first symptoms of the anomaly appear when the plant is flowering and filling pods. The first part of the plant affected is the growing point which dries down and dies quickly followed by the upper leaves which die as well. The pods at the top of the plant are deformed and the plant dies from the top down.

The cause of the anomaly is unknown and researchers speculate it could be anything from a fungus, virus, bacteria, nutritional, or something completely unknown. The anomaly was first noticed about a year ago in Mato Grosso and Goias in the higher and flater regions of the Mato Grosso Plateau.

No preventive measures are recommended since the cause is unknown. Farmers and researchers have tried spraying the affected plants with the same fungicides that they use to control soybean rust, but the fungicides had no affect on the problem.

Researchers are sending samples of the affected plants to university laboratories throughout Brazil in an attempt to identify a cause of the anomaly. They suspect that it might be more widespread than what has been reported and they are asking farmers help in identifying the extent of the problem.

This new anomaly comes on the heels of "Mad Soybeans 2", which received widespread press attention earlier in the growing season. Mad Soybeans 2 was first identified in Brazilian soybean fields in the 1990's, but it only became a significant concern over the last four years. The causal organism of Mad Soybeans 2 is also unknown, but the amount of Mad Soybeans 2 reported in 2010/11 is significantly lower than in 2009/10, in some regions as much as 40% lower.