Mad Soybean disease spreading in Brazil

A devastating soybean disease is slowly spreading throughout Brazil. It is call mad soybean or soja louca disease. Plants never mature to produce seeds and simply rot away causing crop losses of up to 60%. The Brazilian province hardest hit by this new, mystery disease is Mato Grosso but it is spreading slowly south to the cooler areas as well. This is the second serious disease to hit the soybean growing areas. Previously soy Asian rust attacked the fields leading farmers to lobby the government for permission to use more effective fungicides.

There does not seem to be any treatment or cure for mad soybean disease, but there are some suspects. A black mite(tiny spiderlike arthropod) has been associated with the disease and may be spreading it. Statistics vary, but 50 to 78% of the soybeans grown in Brazil are genetically modified. If the plants are genetically alike then they would be equally suseptible to disease. The most common GM is to make the plants resistant to the herbicide Glyphosate. These plants are called Roundup Ready. The farmer can then spray his crop with the herbicide, killing the weeds and leaving the soybeans standing. Contributing to the incidence of plant disease is the no-till method of farming in which the farmer can simply spray herbicide on the weeds and leave them in the field. While the crop is growing there is no cultivation or removal of dead weeds.

There is growing suspicion that Glyphosate tolerant GM plants are more suseptible to plant diseases. These plants are tolerant of Glyphosate(Roundup) but have reduced nutrient intake leaving them weaker and more apt to succumb to disease.

"GM soy is sprayed with glyphosate. There is a well-documented link between glyphosate and increased plant diseases. Don Huber, plant pathologist and professor emeritus at Purdue University, said, “There are more than 40 diseases reported with use of glyphosate, and that number keeps growing as people recognize the association [between glyphosate and disease].”

The US remains the biggest producer of soybeans. The crop was estimated to be worth $31.9 billion in 2009 in the US. A drop in production of 40 to 60% would be devastating to farmers. This crop is gaining worldwide importance in fighting world hunger. Soybeans are used in many ways, directly as cooked beans, processed in myriad ways but also are an important high protein animal feed.